I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

However I am assuming the NS article is based on genetic evidence of the actual size of the founding bottleneck, not based on the theoretical minimum.

Then again, I haven’t read it. Perhaps you could share it somehow, or at least give the title and author.

I would say that for places like Easter Island where the inhabitants came across in small craft, they would have numbered in the tens, at most…

dv said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

However I am assuming the NS article is based on genetic evidence of the actual size of the founding bottleneck, not based on the theoretical minimum.

Then again, I haven’t read it. Perhaps you could share it somehow, or at least give the title and author.

The NS article is “Finding Sahul” by Graham Lawton.
It refers to work by “Corey Bradshaw of Flinders university … They modelled the demographics of colonisation, taking account of typical hunter-gatherer fertility rates and longevity and the ecological conditions they would have encountered after landing …”

So not genetic evidence, or at least not mentioned in the NS article.

p.s. How is your journey crossing the event horizon of the black hole thread going?

More details of the Corey Bradshaw research here:

https://natureecoevocommunity.nature.com/users/30592-corey-bradshaw/posts/48557-modelling-reveals-first-australians-arrived-in-large-groups-using-complex-technologies

The Rev Dodgson said:

More details of the Corey Bradshaw research here:

https://natureecoevocommunity.nature.com/users/30592-corey-bradshaw/posts/48557-modelling-reveals-first-australians-arrived-in-large-groups-using-complex-technologies

A paper referencing Bradshaw:

Early human settlement of Sahul was not an accident

dv said:

The Rev Dodgson said:

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

>Scrunches up eyes<

Are we assuming she’s pregnant with at least one male child?

dv said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

However I am assuming the NS article is based on genetic evidence of the actual size of the founding bottleneck, not based on the theoretical minimum.

Then again, I haven’t read it. Perhaps you could share it somehow, or at least give the title and author.

One pregnant female is the correct answer.

But that relies on a low number of deadly recessive mutations to start with. I’ve heard it said that each human carries an average of 3 deadly recessive mutations.

The number of H sapiens people that crossed over from Africa to Europe has been estimated as “the size of a school excursion”. Of order 400 people.

The number of cheetahs that survived the genetic bottleneck about 10,000 years ago – still looking that one up. Drat, no-one will say, but very much less than 400 individuals. If I was to make a wild guess by comparing the homozygosity of humans to that of cheetahs from https://www.pnas.org/content/pnas/84/2/508.full.pdf then I’d guess at about 1/10 of that human 400, about 40 individuals.

Lord Howe Island stick insect survived for at least hundreds of years with a population of just 24 individuals.

The Wollomai pine went through a bottleneck of “fewer than 100” individuals.

mollwollfumble said:

dv said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

However I am assuming the NS article is based on genetic evidence of the actual size of the founding bottleneck, not based on the theoretical minimum.

Then again, I haven’t read it. Perhaps you could share it somehow, or at least give the title and author.

One pregnant female is the correct answer.

But that relies on a low number of deadly recessive mutations to start with. I’ve heard it said that each human carries an average of 3 deadly recessive mutations.

The number of H sapiens people that crossed over from Africa to Europe has been estimated as “the size of a school excursion”. Of order 400 people.

The number of cheetahs that survived the genetic bottleneck about 10,000 years ago – still looking that one up. Drat, no-one will say, but very much less than 400 individuals. If I was to make a wild guess by comparing the homozygosity of humans to that of cheetahs from https://www.pnas.org/content/pnas/84/2/508.full.pdf then I’d guess at about 1/10 of that human 400, about 40 individuals.

Lord Howe Island stick insect survived for at least hundreds of years with a population of just 24 individuals.

The Wollomai pine went through a bottleneck of “fewer than 100” individuals.

OK, so one pregnant female is not totally impossible, but let’s re-phrase the question:

What is the minimum number of individuals that allows a group of large mammals to have a reasonable chance of surviving and multiplying in a remote location with no contact with other groups of the same species?

Where by reasonable chance I mean some arbitrary figure like say 25%.

Or a graph of probability of survival vs number in original group would be good.

The book “The theory of island biogeography” by Robert H MacArthur and Edward O Wilson might give a better answer. There are copies around in various libraries. This was the seminal book that launched the Insular biogeography field of science.

I also keep in mind that there are various islands around the world where numbers of new colonising animals and plants are recorded by biologists.

Surtsey is one of them.

Insects arrived on Surtsey soon after its formation, and were first detected in 1964. The original arrivals were flying insects, carried to the island by winds and their own power. Some were believed to have been blown across from as far away as mainland Europe. Later insect life arrived on floating driftwood, and both live animals and carcasses washed up on the island. When a large, grass-covered tussock was washed ashore in 1974, scientists took half of it for analysis and discovered 663 land invertebrates, mostly mites and springtails, the great majority of which had survived the crossing.

The establishment of insect life provided some food for birds, and birds in turn helped many species to become established on the island. The bodies of dead birds provide sustenance for carnivorous insects, while the fertilisation of the soil and resulting promotion of plant life provides a viable habitat for herbivorous insects.

Some higher forms of land life are now colonising the soil of Surtsey. The first earthworm was found in a soil sample in 1993, probably carried over from Heimaey by a bird. However, the next year earthworms were not found. Slugs were found in 1998, and appeared to be similar to varieties found in the southern Icelandic mainland. Spiders and beetles have also become established.

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

Going back to Australia – two radically different skull types have been found in Australia, robust skull and gracile skull. The question arises as to whether these were two separate small migrations or a single large one. Robust skulls are still found among living aborigines – or at least among living aborigines back in 1788 – I’ve no idea whether any still survive now. If you see or have seen any evidence that aboriginal people with robust skulls still exist, please reply to this post.

The gracile skull is not greatly different from humans elsewhere around the world. The main distinction being a slightly thicker brow ridge and flat wide nose.

The robust skull is very different, as different as the neanderthal is from sapiens. Chin receding to nonexistent, greatly protruding front of the jaw (lips), heavy thick brow ridge and strongly sloping forehead. First became famous in Australia from the Kow Swamp fossils. Here is a picture of Kow Swamp 1. As you can see, very very different from the familiar H sapiens skull, but it is still counted as H sap.

mollwollfumble said:

The book “The theory of island biogeography” by Robert H MacArthur and Edward O Wilson might give a better answer. There are copies around in various libraries. This was the seminal book that launched the Insular biogeography field of science.

I also keep in mind that there are various islands around the world where numbers of new colonising animals and plants are recorded by biologists.

Surtsey is one of them.

Insects arrived on Surtsey soon after its formation, and were first detected in 1964. The original arrivals were flying insects, carried to the island by winds and their own power. Some were believed to have been blown across from as far away as mainland Europe. Later insect life arrived on floating driftwood, and both live animals and carcasses washed up on the island. When a large, grass-covered tussock was washed ashore in 1974, scientists took half of it for analysis and discovered 663 land invertebrates, mostly mites and springtails, the great majority of which had survived the crossing.

The establishment of insect life provided some food for birds, and birds in turn helped many species to become established on the island. The bodies of dead birds provide sustenance for carnivorous insects, while the fertilisation of the soil and resulting promotion of plant life provides a viable habitat for herbivorous insects.

Some higher forms of land life are now colonising the soil of Surtsey. The first earthworm was found in a soil sample in 1993, probably carried over from Heimaey by a bird. However, the next year earthworms were not found. Slugs were found in 1998, and appeared to be similar to varieties found in the southern Icelandic mainland. Spiders and beetles have also become established.

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

Going back to Australia – two radically different skull types have been found in Australia, robust skull and gracile skull. The question arises as to whether these were two separate small migrations or a single large one. Robust skulls are still found among living aborigines – or at least among living aborigines back in 1788 – I’ve no idea whether any still survive now. If you see or have seen any evidence that aboriginal people with robust skulls still exist, please reply to this post.

The gracile skull is not greatly different from humans elsewhere around the world. The main distinction being a slightly thicker brow ridge and flat wide nose.

The robust skull is very different, as different as the neanderthal is from sapiens. Chin receding to nonexistent, greatly protruding front of the jaw (lips), heavy thick brow ridge and strongly sloping forehead. First became famous in Australia from the Kow Swamp fossils. Here is a picture of Kow Swamp 1. As you can see, very very different from the familiar H sapiens skull, but it is still counted as H sap.

Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

mollwollfumble said:

mollwollfumble said:

The book “The theory of island biogeography” by Robert H MacArthur and Edward O Wilson might give a better answer. There are copies around in various libraries. This was the seminal book that launched the Insular biogeography field of science.

I also keep in mind that there are various islands around the world where numbers of new colonising animals and plants are recorded by biologists.

Surtsey is one of them.

Insects arrived on Surtsey soon after its formation, and were first detected in 1964. The original arrivals were flying insects, carried to the island by winds and their own power. Some were believed to have been blown across from as far away as mainland Europe. Later insect life arrived on floating driftwood, and both live animals and carcasses washed up on the island. When a large, grass-covered tussock was washed ashore in 1974, scientists took half of it for analysis and discovered 663 land invertebrates, mostly mites and springtails, the great majority of which had survived the crossing.

The establishment of insect life provided some food for birds, and birds in turn helped many species to become established on the island. The bodies of dead birds provide sustenance for carnivorous insects, while the fertilisation of the soil and resulting promotion of plant life provides a viable habitat for herbivorous insects.

Some higher forms of land life are now colonising the soil of Surtsey. The first earthworm was found in a soil sample in 1993, probably carried over from Heimaey by a bird. However, the next year earthworms were not found. Slugs were found in 1998, and appeared to be similar to varieties found in the southern Icelandic mainland. Spiders and beetles have also become established.

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

Going back to Australia – two radically different skull types have been found in Australia, robust skull and gracile skull. The question arises as to whether these were two separate small migrations or a single large one. Robust skulls are still found among living aborigines – or at least among living aborigines back in 1788 – I’ve no idea whether any still survive now. If you see or have seen any evidence that aboriginal people with robust skulls still exist, please reply to this post.

The gracile skull is not greatly different from humans elsewhere around the world. The main distinction being a slightly thicker brow ridge and flat wide nose.

The robust skull is very different, as different as the neanderthal is from sapiens. Chin receding to nonexistent, greatly protruding front of the jaw (lips), heavy thick brow ridge and strongly sloping forehead. First became famous in Australia from the Kow Swamp fossils. Here is a picture of Kow Swamp 1. As you can see, very very different from the familiar H sapiens skull, but it is still counted as H sap.

Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

For genetic variation among aborigines see also Current Anthropology. http://canovanograms.tripod.com/pintubi1/

“Paleoanthropology is the study of mankind with respect to his prehistoric past. In this report, we discuss a skull from Australia (PINTUBI-1) and the implications of it’s special morphologies (characteristic structure). Our previous installment, KOW SWAMP – IS IT HOMO ERECTUS – PART 2, can now be found at: http://home.twmi.rr.com/canovan/kowswamp/kowswamp.htm”

“The controversial Pintubi-1 skull of Australia (pictured above) is a paradox of paleoanthropology. As a hominid fossil, its so young that it has been assigned to a tribe that survived into the last century. A modern aboriginal skull. Yet its morphology could be described as archaic.
The skulls history is shrouded in mystery (not unlike others from the down under). Even without documentation, its age and Australoid identity are indisputable. The man it belonged to lived very recently (in paleo-terms), likely in the 1800s or later. It is in perfect condition and shows no signs of antiquity. The skull was discovered or obtained around 1905 near the lower Darling River in New South Wales, Australia. Beyond that, all we are able to determine is that it is said to be a large adult 50 year old male from the Pintubi tribe.

The last of the Pintubis (also called Bindaboos) surrendered their nomadic Stone Age life styles in the 1960s. They were probably the final example of unaltered stone age culture in Australia. The subject skull, modern in age, yet archaic in structure.

There ought to be, I’m temped to say must be, ancient genetic markers among some aborigines that still exist. The challenge may be in finding them.

The left skull here is a modern aboriginal skull. Pintubi 1. A huge amount of genetic variation among the aborigines.

Rule 303 said:

dv said:

The Rev Dodgson said:

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

>Scrunches up eyes<

Are we assuming she’s pregnant with at least one male child?

Yes

The Rev Dodgson said:

dv said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

However I am assuming the NS article is based on genetic evidence of the actual size of the founding bottleneck, not based on the theoretical minimum.

Then again, I haven’t read it. Perhaps you could share it somehow, or at least give the title and author.

The NS article is “Finding Sahul” by Graham Lawton.
It refers to work by “Corey Bradshaw of Flinders university … They modelled the demographics of colonisation, taking account of typical hunter-gatherer fertility rates and longevity and the ecological conditions they would have encountered after landing …”

So not genetic evidence, or at least not mentioned in the NS article.

p.s. How is your journey crossing the event horizon of the black hole thread going?

Eh I’ll leave you to it.

Thanks for the extra info but again it appears that they have modelled based on typical cases, so it shouldn’t be surprising that the number is much larger than the bare minimum.

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

Rule 303 said:

dv said:

The Rev Dodgson said:

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

One pregnant female.

>Scrunches up eyes<

Are we assuming she’s pregnant with at least one male child?

And also that both the male child and mother survive long enough to parent at least one female child, and the female child and at least one male child survive long enough to start the next cycle.

The probability of that must be pretty close to zero.

OTOH, with a mixed group of say 20 I don’t see why the chance of long term survival would not be reasonably high.

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

The Rev Dodgson said:

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Or starving.

The Rev Dodgson said:

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Modern humans (ie humans of the last 200000 years ) are apex predators. I would think the major risk in moving to a new area is either not finding enough prey, or not being able to hunt the weird animals there due to lack of experience.

The Rev Dodgson said:

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Thylacoleo was like pretty aggressive.

dv said:

The Rev Dodgson said:

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Modern humans (ie humans of the last 200000 years ) are apex predators. I would think the major risk in moving to a new area is either not finding enough prey, or not being able to hunt the weird animals there due to lack of experience.

Diprotodon was likely a slow moving herbivore (browser). Plenty of feed in one of theem.

I suppose the other question is, over what time period?

It’s not as though a few hundred people canoed here one day and the stopped… right? Seems more reasonable to suggest a long initial migration over at least thousands of years.

Michael V said:

The Rev Dodgson said:

dv said:

The other things is that humans work best in groups. Even in HG societies there is some measure of specialisation and cooperation. You’re asking about mammals generally but humans are probably going to benefit from being in a bigger group more than, say, rats are.

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Thylacoleo was like pretty aggressive.

Were any megafauna around then?

The Rev Dodgson said:

And also that both the male child and mother survive long enough to parent at least one female child, and the female child and at least one male child survive long enough to start the next cycle.

The probability of that must be pretty close to zero.

It would depend on the length of the fertile life of the animals and the length of time taken to reach maturity. Again: much more likely for a rat than a person.

Still, I think “close to zero” seems a bit pessimistic even for humans. 16 year old gravid arrives and produces a male, at 32 she mates with the male, and they have the rest of her fertile life (10 years or whatever) to produce offspring. I mean it’s not a slam dunk but seems like they’d have a better than 1% chance.

Tamb said:

Michael V said:

The Rev Dodgson said:

What was the probability of being killed by some other animal in Australia 70,000 years ago?

Thylacoleo was like pretty aggressive.

Were any megafauna around then?

Sure. Diprotodon at least.

CTTOI, given that the first Australians were maritime folk, maybe they were also able to catch fish, in which case they would not require a huge learning curve just from moving to a new shore.

Michael V said:

Tamb said:

Michael V said:

Thylacoleo was like pretty aggressive.

Were any megafauna around then?

Sure. Diprotodon at least.

Some of them would vie with man for top predator.

Aborigines once occupied Kangaroo Island (SA), but after hundreds (maybe thousands) of years they either died out or moved to the mainland. Anthropologists formed the opinion that over the long time the Island could not support a large population of people and that around 500 would be needed to maintain genetic diversity.

PermeateFree said:

Aborigines once occupied Kangaroo Island (SA), but after hundreds (maybe thousands) of years they either died out or moved to the mainland. Anthropologists formed the opinion that over the long time the Island could not support a large population of people and that around 500 would be needed to maintain genetic diversity.

Wouldn’t have been an island for a great deal of the time they were using it.

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

11 ships carrying 1530 people

On 13 May 1787, the First Fleet of 11 ships and about 1,530 people (736 convicts, 17 convicts’ children, 211 marines, 27 marines’ wives, 14 marines’ children and about 300 officers and others) under the command of Captain Arthur Phillip set sail for Botany Bay. A few days after arrival at Botany Bay the fleet moved to the more suitable Port Jackson where a settlement was established at Sydney Cove on 26 January 1788. This date later became Australia’s national day, Australia Day. The colony was formally proclaimed by Governor Phillip on 7 February 1788 at Sydney. Sydney Cove offered a fresh water supply and a safe harbour, which Philip famously described as:[1

https://en.wikipedia.org/wiki/History_of_Australia_(1788%E2%80%931850)

>>>That sounds like a ridiculously large number to me, and also ridiculously specific.

Log books contain supplies, number of people

sibeen said:

PermeateFree said:

Aborigines once occupied Kangaroo Island (SA), but after hundreds (maybe thousands) of years they either died out or moved to the mainland. Anthropologists formed the opinion that over the long time the Island could not support a large population of people and that around 500 would be needed to maintain genetic diversity.

Wouldn’t have been an island for a great deal of the time they were using it.

Also, it’s not exactly isolated, there’s easy access to the mainland, so inhabiting it wouldn’t mean genetic isolation.

Also, also, there are much smaller islands that have supported self-supporting populations. Ki is about 20 times the size of North Sentinel Island for instance.

But I guess I’d need to read the paper to comment intelligently.

sibeen said:

PermeateFree said:

Aborigines once occupied Kangaroo Island (SA), but after hundreds (maybe thousands) of years they either died out or moved to the mainland. Anthropologists formed the opinion that over the long time the Island could not support a large population of people and that around 500 would be needed to maintain genetic diversity.

Wouldn’t have been an island for a great deal of the time they were using it.

They initially would have walked over during the last Ice Age, but were cut off by rising sealevels as was the case for Tasmania, but there the island was large enough to support a larger and more viable population.

Log books are always ridiculously specific.

Tau.Neutrino said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

11 ships carrying 1530 people

On 13 May 1787, the First Fleet of 11 ships and about 1,530 people (736 convicts, 17 convicts’ children, 211 marines, 27 marines’ wives, 14 marines’ children and about 300 officers and others) under the command of Captain Arthur Phillip set sail for Botany Bay. A few days after arrival at Botany Bay the fleet moved to the more suitable Port Jackson where a settlement was established at Sydney Cove on 26 January 1788. This date later became Australia’s national day, Australia Day. The colony was formally proclaimed by Governor Phillip on 7 February 1788 at Sydney. Sydney Cove offered a fresh water supply and a safe harbour, which Philip famously described as:

Oh dear

Tau.Neutrino said:

Log books are always ridiculously specific.

The people who came on the First Fleet were not the first settlers in Australia

dv said:

Tau.Neutrino said:

Log books are always ridiculously specific.

The people who came on the First Fleet were not the first settlers in Australia

Yes that title belongs to aborigines, so that page needs some editing

dv said:

sibeen said:

PermeateFree said:

Aborigines once occupied Kangaroo Island (SA), but after hundreds (maybe thousands) of years they either died out or moved to the mainland. Anthropologists formed the opinion that over the long time the Island could not support a large population of people and that around 500 would be needed to maintain genetic diversity.

Wouldn’t have been an island for a great deal of the time they were using it.

Also, it’s not exactly isolated, there’s easy access to the mainland, so inhabiting it wouldn’t mean genetic isolation.

Also, also, there are much smaller islands that have supported self-supporting populations. Ki is about 20 times the size of North Sentinel Island for instance.

But I guess I’d need to read the paper to comment intelligently.

Size is not the main feature, but the ability of the island to provide for the inhabitants.

>>Kangaroo Island is Australia’s third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia 112 km (70 mi) southwest of Adelaide. Its closest point to the mainland is Snapper Point in Backstairs Passage, which is 13.5 km (8.4 mi) from the Fleurieu Peninsula.

The native population of Aboriginal Australians that once occupied the island disappeared from the archaeological record when the land became an island following rising sea levels several thousand years ago. It was subsequently settled intermittently by sealers and whalers in the early 19th century, and from 1836 on a permanent basis during the establishment of the colony of South Australia.<<

Wiki

PermeateFree said:

dv said:

sibeen said:

Wouldn’t have been an island for a great deal of the time they were using it.

Also, it’s not exactly isolated, there’s easy access to the mainland, so inhabiting it wouldn’t mean genetic isolation.

Also, also, there are much smaller islands that have supported self-supporting populations. Ki is about 20 times the size of North Sentinel Island for instance.

But I guess I’d need to read the paper to comment intelligently.

Size is not the main feature, but the ability of the island to provide for the inhabitants.

>>Kangaroo Island is Australia’s third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia 112 km (70 mi) southwest of Adelaide. Its closest point to the mainland is Snapper Point in Backstairs Passage, which is 13.5 km (8.4 mi) from the Fleurieu Peninsula.

The native population of Aboriginal Australians that once occupied the island disappeared from the archaeological record when the land became an island following rising sea levels several thousand years ago. It was subsequently settled intermittently by sealers and whalers in the early 19th century, and from 1836 on a permanent basis during the establishment of the colony of South Australia.<<

Wiki

Cheers.

Minimum viable population

An MVP of 500 to 1,000

Application

MVP does not take external intervention into account. Thus, it is useful for conservation managers and environmentalists; a population may be increased above the MVP using a captive breeding program, or by bringing other members of the species in from other reserves.

There is naturally some debate on the accuracy of PVAs, since a wide variety of assumptions are generally required for forecasting; however, the important consideration is not absolute accuracy, but promulgation of the concept that each species indeed has an MVP, which at least can be approximated for the sake of conservation biology and Biodiversity Action Plans.

There is a marked trend for insularity, surviving genetic bottlenecks and r-strategy to allow far lower MVPs than average. Conversely, taxa easily affected by inbreeding depression – having high MVPs – are often decidedly K-strategists, with low population densities while occurring over a wide range. An MVP of 500 to 1,000 has often been given as an average for terrestrial vertebrates when inbreeding or genetic variability is ignored. When inbreeding effects are included, estimates of MVP for many species are in the thousands. Based on a meta-analysis of reported values in the literature for many species, Traill et al. reported concerning vertebrates “a cross-species frequency distribution of MVP with a median of 4169 individuals (95% CI = 3577–5129).”

Tau.Neutrino said:

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

11 ships carrying 1530 people

On 13 May 1787, the First Fleet of 11 ships and about 1,530 people (736 convicts, 17 convicts’ children, 211 marines, 27 marines’ wives, 14 marines’ children and about 300 officers and others) under the command of Captain Arthur Phillip set sail for Botany Bay. A few days after arrival at Botany Bay the fleet moved to the more suitable Port Jackson where a settlement was established at Sydney Cove on 26 January 1788. This date later became Australia’s national day, Australia Day. The colony was formally proclaimed by Governor Phillip on 7 February 1788 at Sydney. Sydney Cove offered a fresh water supply and a safe harbour, which Philip famously described as:

Almost starved in first year. Even after killing almost every seal.

but that MVP from Wikipedia 500 – 4169 differs with the New Scientist MVP of 80 -160 ?

https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated/

Some comments
https://worldbuilding.stackexchange.com/questions/3/what-is-the-minimum-human-population-necessary-for-a-sustainable-colony

Tau.Neutrino said:

but that MVP from Wikipedia 500 – 4169 differs with the New Scientist MVP of 80 -160 ?

https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated/

Some comments
https://worldbuilding.stackexchange.com/questions/3/what-is-the-minimum-human-population-necessary-for-a-sustainable-colony

But are they thinking that this population size would persist over thousands of years? I think they would hope they would have some visitors and new blood over that period.

A long way back on the foru there was a thread in which it was mentioned that almost all of Western Europe was related to one woman and seven men who they suggested were the first to cross the alps.

I remember thinking there was an Eve.

the population viability stuff that was posted about mars colonisation had the 50/500 rule.

not much outside interaction there.

Arts said:

the population viability stuff that was posted about mars colonisation had the 50/500 rule.

not much outside interaction there.

Well there could be.

In the case of Australia of course no-one knows how much contact there was between the first settlers and the populations on the islands they came from.

There might have been frequent travel in both directions for all we know.

PermeateFree said:

Tau.Neutrino said:

but that MVP from Wikipedia 500 – 4169 differs with the New Scientist MVP of 80 -160 ?

https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated/

Some comments
https://worldbuilding.stackexchange.com/questions/3/what-is-the-minimum-human-population-necessary-for-a-sustainable-colony

But are they thinking that this population size would persist over thousands of years? I think they would hope they would have some visitors and new blood over that period.

If they have access to DNA information they could try to maximize survival that way by avoiding inbreeding

Tau.Neutrino said:

PermeateFree said:

Tau.Neutrino said:

but that MVP from Wikipedia 500 – 4169 differs with the New Scientist MVP of 80 -160 ?

https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated/

Some comments
https://worldbuilding.stackexchange.com/questions/3/what-is-the-minimum-human-population-necessary-for-a-sustainable-colony

But are they thinking that this population size would persist over thousands of years? I think they would hope they would have some visitors and new blood over that period.

If they have access to DNA information they could try to maximize survival that way by avoiding inbreeding

You don’t need DNA information as Aborigines knew about inbreeding by allocating “skin type” where they cannot marry another with the same skin type. The following link of Australian Aboriginal kinship, goes into it in some detail.

Most communal animals have a system where either the males, or with other groups the females move away in search of unrelated groups in order to breed. Maybe white folk missed that lecture. :)

PermeateFree said:

Tau.Neutrino said:

PermeateFree said:

But are they thinking that this population size would persist over thousands of years? I think they would hope they would have some visitors and new blood over that period.

If they have access to DNA information they could try to maximize survival that way by avoiding inbreeding

You don’t need DNA information as Aborigines knew about inbreeding by allocating “skin type” where they cannot marry another with the same skin type. The following link of Australian Aboriginal kinship, goes into it in some detail.

Most communal animals have a system where either the males, or with other groups the females move away in search of unrelated groups in order to breed. Maybe white folk missed that lecture. :)

https://en.wikipedia.org/wiki/Australian_Aboriginal_kinship

PermeateFree said:

PermeateFree said:

Tau.Neutrino said:

If they have access to DNA information they could try to maximize survival that way by avoiding inbreeding

You don’t need DNA information as Aborigines knew about inbreeding by allocating “skin type” where they cannot marry another with the same skin type. The following link of Australian Aboriginal kinship, goes into it in some detail.

Most communal animals have a system where either the males, or with other groups the females move away in search of unrelated groups in order to breed. Maybe white folk missed that lecture. :)

https://en.wikipedia.org/wiki/Australian_Aboriginal_kinship

Interesting, have any white populations have tried that?

Tau.Neutrino said:

PermeateFree said:

PermeateFree said:

You don’t need DNA information as Aborigines knew about inbreeding by allocating “skin type” where they cannot marry another with the same skin type. The following link of Australian Aboriginal kinship, goes into it in some detail.

Most communal animals have a system where either the males, or with other groups the females move away in search of unrelated groups in order to breed. Maybe white folk missed that lecture. :)

https://en.wikipedia.org/wiki/Australian_Aboriginal_kinship

Interesting, have any white populations have tried that?

We would probably be a lot smarter if they had. The constant wars in Europe of which young women were part of the booty, they didn’t have to worry too much, although some royalty were quite incestuous.

7

SCIENCE said:

7

Its somewhere between 50 and 5000.

The 6-moiety systems are quite elegant, really.

dv said:

The 6-moiety systems are quite elegant, really.

yeah you remembered more correctly than us

https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-1795.2007.00154.x

mollwollfumble said:

mollwollfumble said:

The book “The theory of island biogeography” by Robert H MacArthur and Edward O Wilson might give a better answer. There are copies around in various libraries. This was the seminal book that launched the Insular biogeography field of science.

I also keep in mind that there are various islands around the world where numbers of new colonising animals and plants are recorded by biologists.

Surtsey is one of them.

Insects arrived on Surtsey soon after its formation, and were first detected in 1964. The original arrivals were flying insects, carried to the island by winds and their own power. Some were believed to have been blown across from as far away as mainland Europe. Later insect life arrived on floating driftwood, and both live animals and carcasses washed up on the island. When a large, grass-covered tussock was washed ashore in 1974, scientists took half of it for analysis and discovered 663 land invertebrates, mostly mites and springtails, the great majority of which had survived the crossing.

The establishment of insect life provided some food for birds, and birds in turn helped many species to become established on the island. The bodies of dead birds provide sustenance for carnivorous insects, while the fertilisation of the soil and resulting promotion of plant life provides a viable habitat for herbivorous insects.

Some higher forms of land life are now colonising the soil of Surtsey. The first earthworm was found in a soil sample in 1993, probably carried over from Heimaey by a bird. However, the next year earthworms were not found. Slugs were found in 1998, and appeared to be similar to varieties found in the southern Icelandic mainland. Spiders and beetles have also become established.

The Rev Dodgson said:

I just read in New Scientist that modelling studies showed that the initial number of settlers in Australia must have been at least 1300.

That sounds like a ridiculously large number to me, and also ridiculously specific.

Does anyone know of other studies on this question? Not necessarily related to Australia, or even humans.

What is the minimum number of individuals that allows a group of large mammals to survive and multiply in a remote location with no contact with other groups of the same species?

Going back to Australia – two radically different skull types have been found in Australia, robust skull and gracile skull. The question arises as to whether these were two separate small migrations or a single large one. Robust skulls are still found among living aborigines – or at least among living aborigines back in 1788 – I’ve no idea whether any still survive now. If you see or have seen any evidence that aboriginal people with robust skulls still exist, please reply to this post.

The gracile skull is not greatly different from humans elsewhere around the world. The main distinction being a slightly thicker brow ridge and flat wide nose.

The robust skull is very different, as different as the neanderthal is from sapiens. Chin receding to nonexistent, greatly protruding front of the jaw (lips), heavy thick brow ridge and strongly sloping forehead. First became famous in Australia from the Kow Swamp fossils. Here is a picture of Kow Swamp 1. As you can see, very very different from the familiar H sapiens skull, but it is still counted as H sap.

Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

I’m going to say that I don’t know. However, I could probably suggest that you’d better do some more reading on the subject. ie: http://downloads.hindawi.com/archive/2011/632484.pdf

Of course if she were pregnant with opposite sex twins then you’re away

dv said:

Of course if she were pregnant with opposite sex twins then you’re away

Heinlein once spent some pages discussing whether opposite twins who loved each other should have children. His conclusion was that if they didn’t have genetic problems then it probably wouldn’t be a problem…you needed bad genetics somewhere for inbreeding problems to eventuate.

sarahs mum said:

dv said:

Of course if she were pregnant with opposite sex twins then you’re away

Heinlein once spent some pages discussing whether opposite twins who loved each other should have children. His conclusion was that if they didn’t have genetic problems then it probably wouldn’t be a problem…you needed bad genetics somewhere for inbreeding problems to eventuate.

Molly will be able to quote the passages shortly as he recently bought Time Enough For Love.

roughbarked said:

mollwollfumble said:

mollwollfumble said:

The book “The theory of island biogeography” by Robert H MacArthur and Edward O Wilson might give a better answer. There are copies around in various libraries. This was the seminal book that launched the Insular biogeography field of science.

I also keep in mind that there are various islands around the world where numbers of new colonising animals and plants are recorded by biologists.

Surtsey is one of them.

Insects arrived on Surtsey soon after its formation, and were first detected in 1964. The original arrivals were flying insects, carried to the island by winds and their own power. Some were believed to have been blown across from as far away as mainland Europe. Later insect life arrived on floating driftwood, and both live animals and carcasses washed up on the island. When a large, grass-covered tussock was washed ashore in 1974, scientists took half of it for analysis and discovered 663 land invertebrates, mostly mites and springtails, the great majority of which had survived the crossing.

The establishment of insect life provided some food for birds, and birds in turn helped many species to become established on the island. The bodies of dead birds provide sustenance for carnivorous insects, while the fertilisation of the soil and resulting promotion of plant life provides a viable habitat for herbivorous insects.

Some higher forms of land life are now colonising the soil of Surtsey. The first earthworm was found in a soil sample in 1993, probably carried over from Heimaey by a bird. However, the next year earthworms were not found. Slugs were found in 1998, and appeared to be similar to varieties found in the southern Icelandic mainland. Spiders and beetles have also become established.

Going back to Australia – two radically different skull types have been found in Australia, robust skull and gracile skull. The question arises as to whether these were two separate small migrations or a single large one. Robust skulls are still found among living aborigines – or at least among living aborigines back in 1788 – I’ve no idea whether any still survive now. If you see or have seen any evidence that aboriginal people with robust skulls still exist, please reply to this post.

The gracile skull is not greatly different from humans elsewhere around the world. The main distinction being a slightly thicker brow ridge and flat wide nose.

The robust skull is very different, as different as the neanderthal is from sapiens. Chin receding to nonexistent, greatly protruding front of the jaw (lips), heavy thick brow ridge and strongly sloping forehead. First became famous in Australia from the Kow Swamp fossils. Here is a picture of Kow Swamp 1. As you can see, very very different from the familiar H sapiens skull, but it is still counted as H sap.

Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

I’m going to say that I don’t know. However, I could probably suggest that you’d better do some more reading on the subject. ie: http://downloads.hindawi.com/archive/2011/632484.pdf

hmm. in forensic anthropology a brow ridge is one of the indicators of likelihood of male.. so to say no brow ridge is misleading.

sibeen said:

sarahs mum said:

dv said:

Of course if she were pregnant with opposite sex twins then you’re away

Heinlein once spent some pages discussing whether opposite twins who loved each other should have children. His conclusion was that if they didn’t have genetic problems then it probably wouldn’t be a problem…you needed bad genetics somewhere for inbreeding problems to eventuate.

Molly will be able to quote the passages shortly as he recently bought Time Enough For Love.

I thought it was Time enough for Love. But it was decades ago.

sarahs mum said:

sibeen said:

sarahs mum said:

Heinlein once spent some pages discussing whether opposite twins who loved each other should have children. His conclusion was that if they didn’t have genetic problems then it probably wouldn’t be a problem…you needed bad genetics somewhere for inbreeding problems to eventuate.

Molly will be able to quote the passages shortly as he recently bought Time Enough For Love.

I thought it was Time enough for Love. But it was decades ago.

Yes!
You both know the book. Good on you!

Arts said:

> Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

hmm. in forensic anthropology a brow ridge is one of the indicators of likelihood of male.. so to say no brow ridge is misleading.

In primate species with a big differences between the sexes, yes. Humans have less difference, hip width is a better indicator.

Do neanderthals, denisovans etc. have big differences between the sexes?

I don’t have one and cytogeneticists tell me I’m male.

mollwollfumble said:

Arts said:

> Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

hmm. in forensic anthropology a brow ridge is one of the indicators of likelihood of male.. so to say no brow ridge is misleading.

In primate species with a big differences between the sexes, yes. Humans have less difference, hip width is a better indicator.

Do neanderthals, denisovans etc. have big differences between the sexes?

I don’t have one and cytogeneticists tell me I’m male.

TATE on brow ridges is QI, including:

“Prominent supraorbital ridges among modern humans are most common among Australian Aborigines, Papuans, Europeans, and some South Asians.”

mollwollfumble said:

Arts said:

> Compare with european H sap. skull in similar orientation. No brow ridge, vertical forehead, lip area not protruding.

hmm. in forensic anthropology a brow ridge is one of the indicators of likelihood of male.. so to say no brow ridge is misleading.

In primate species with a big differences between the sexes, yes. Humans have less difference, hip width is a better indicator.

Do neanderthals, denisovans etc. have big differences between the sexes?

I don’t have one and cytogeneticists tell me I’m male.

well, humans is what we deal with. Also it’s one of the indicators, no scientist worth their salt would use just one feature.
Ideally a pelvis is a much better indicator fo sex, however, it’s rare to have a full one and, again, width is a supplementary indicator used in totality with other features (like the greater sciatic notch).

In getting back to it, I suspect if I peel away your face and studied your skull I would be able to assign a likely sex of male to you.

>…/cut/….I suspect if I peel away your face and studied your skull I would be able to assign a likely sex of male to you.”

just need follow that up with an invitation to your place for a meal

chuckle

don’t mind me, it’s the heat