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Fundamentals to Evolutionary Biology > Lecture 20 - Human Evolution 1 > Flashcards

Lecture 20 - Human Evolution 1 Flashcards

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1
Q

When was the start of the pleistocene

A

2.58 Myr

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2
Q

When was the start of the holocene

A

11.7 thousand years ago

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3
Q

Hominids

A

Members of the Hominidae e.g. orangutans, Gorillas, Chimpanzees, Humans

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4
Q

Hominins

A

Bipedal hominids, they occur only in the lineage that leads to modern humans

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5
Q

Why are human fossils rare?

A

Until 2 Myr ago hominins lived on the African plains, so the bodies were probably scavenged by predators and skeletons rarely survived intact

Population numbers were low and went through frequent bottlenecks

This means meant that some extinct species are defined from one or just a few fossils so difficult to know whiwhc species are on the direct route to homo sapians

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6
Q

How many species of hominin are alive today?

A

One

Homo sapians

For the last 40,000 years, before that was always at least 2 alive

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7
Q

What is the earliest known fossil able to walk upright?

A

Ardipthecus ramidus

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8
Q

How was Ardipthecus ramidus discovered?

A

Found a single intact skeleton

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9
Q

How tall was the Ardipthecus ramidus fossil?

A

1.2m

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10
Q

When was Ardipthecus ramidus fossil around?

A

4.4 million years ago

Very soon after the split between the human and chimpanzee lineages

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11
Q

What were the features of Ardipthecus ramidus?

A

Had some features more typical of chimpanzees than of modern humans, especially in dentition, but also including oposable big toes which chimpanzees use to cling on to branches

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12
Q

Habitat of Ardipthecus ramidus?

A

Thought to have spent at least some times in trees

This complicates the earlier theories that bipedalism evolved when our ancestors first moved out of the forests onto grasslands of the African savannahs

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13
Q

What is thought to be the direct ancestor of Homo?

A

Australopithecus afarensis

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14
Q

What fossils were found of Australopithecus afarensis?

A

Several fossils including an intact skeleton called lucy

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15
Q

When and where was Lucy the fossil found?

A

3.6 million years ago in Ethiopia in the Afar region

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16
Q

Features of Australopithecus afarensis fossils?

A

Around 1.2M, skull capacity of 375-550cm^3 indicating their brain was no bigger than ardipthecus ramidus

Had skeletal features much more similar to those of modern humans

In particular her pelvis bones and leg bones have modern features, suggesting that she walked much how we walk today

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17
Q

When did Australopithecus africanus appear in the fossil record?

A

3 million years ago

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18
Q

Characteristics of Australopithecus africanus?

A

Slightly taller than A.Afarensis with a bigger brain, and with teeth that are more similar to humans than are those of the earlier species

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19
Q

What is the debate surrounding Australopithecus africanus?

A

Weather it is on the direct line leading to homo or represents a side branch that became extinct

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20
Q

What is the difference between lumpers and splitters?

A

Different paleontological approaches

Lumper prefers as few hominin species as possible and so placing similar fossils in the same species

Splitters emphasizing the differences between individual fossils and so recognizing a greater proliferation of species

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21
Q

What was the first homo species?

A

Homo habilis

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22
Q

Where was Homo habilis found?

A

Olduvai Gorge, part of the African Rift Valley in northern Tanzania

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23
Q

What is the meaning of Homo habilis and why are they called that?

A

Handy man

As the first to be associated with stone tools.

These Olduwan tools were manufactured by splitting flakes from the surfaces of pebbles of flint or basalt to leave a crude chopping or scraping implement

24
Q

Homo habilis skull and its significance?

A

Brain predicted to have an average size of 650cm3, which is 100cm3 larger than any australopithecine

Skull shape suggests that there is a feature of the brain called the bulge of Broca, which is essential for speech was more developed in Homo habilis

25
Q

What did Homo habilis eat?

A

Not a great hunter

Used its Olduwan tools for scavenging meat from carrion, and sometimes became the prey of more successful hunters of the African plains, such as the big cats

26
Q

A significant feature of Paranthropus robustus

A

Had a very robust jaw with large molars and flared cheek bones

Had a cranial capacity of up to 530Cm3

27
Q

How long ago was the fossil of Paranthropus robustus dated?

A

1.5-2 million years ago

28
Q

When was Paranthropus boisei dated?

A

1.3 to 2.3 million years ago

29
Q

Key feature of Paranthropus boisei?

A

Even more speciaclised jaw than P. rubustus

Relatively larger molars with very thick enamel, peg-like small incisors

30
Q

Sexual dimorphism in Paranthropus robustus?

A

Showed size variation of around 24-43Kg suggesting sexual dimorphism

31
Q

Diet of Paranthropus boisei?

A

It is debated but likely adapted for chewing grasses or roots

32
Q

What was the black skull?

A

A skull attributed to Paranthropus aethiopicus (alongside humans, debate on weather this is true)

Dated 2.3 to 2.6 MYA

33
Q

When did Homo erectus exist?

A

1.9 million to 300,000 years ago

34
Q

How tall were Homo erectus?

A

1.8m

35
Q

Homo erectus brain size

A

1225cm3

36
Q

Ecology of Homo erectus?

A

had advanced Acheulean tools, dominated African ecosystem

37
Q

What were the first hominins to move to other parts of the old world?

A

Homo erectus

Fossils fond in Georgia and China from periods soon after the first appearance of species in Africa

38
Q

What was the earliest hominin in Europe?

A

Juvenile specimen found in a cave at Atapuerca, Spain

Dated 800,000 years ago

Usually thought to be Homo antecessor but might be early Homo heidelbergensis

39
Q

When was Homo heidelbergenesis first identified?

A

From a 500,000 year old Jaw from Heidelberg Germany

40
Q

Skull of Homo heidelbergenesis?

A

A mixture of features seen in H. erectus and H. sapiens with a brain size intermediate between the two

41
Q

What replaced Homo heidelbergenesis?

A

Homo neanderthalensis

Around 400,000 years ago

42
Q

Physical features of Homo neanderthalensis

A

Average height of 1.7m and slightly larger brains than H. sapians, probably a feature of their greater robustness.

They displayed features of cold adaptation such as large sinuses for warming air entering through nostrils

43
Q

When and where did Homo neanderthalensis live?

A

Lived throughout Europe between 400,000 to 40,000 years ago

44
Q

When and where did Homo sapiens first appear?

A

In Omo Ehtiopia 195,000 years ago (time is debated)

45
Q

Modern human features of the first Homo Sapien?

A

rounded skull and protruding skin

46
Q

What fossils of Homo Sapiens have been found?

A

Ethiopia 160,000 years ago

Laetoli in Tanzania from 120,000 years ago

Border cave South Africa 110,000 years ago

Klasies River Mouth South Africa 90,000 years ago

47
Q

Where were anatomically modern humans present around 100,000 years ago?

A

Skhul and Qafzeh in the Levant probably as a result of the African population expanding during a relatively warm period shortly after the beginning of the last glacial cycle

48
Q

How was the Denisovans discovered?

A

From small pieces of bone and teeth found in caves in the Altai mountains, Serbia, dated to 40,000 years ago

Useful DNA sequences obtained

Initially thought to be a new species, now look to be an Asian type of Neanderthal

49
Q

Where was Homo floresiensis found?

A

Island of Flores in Indonesia

50
Q

Where was Homo luzonensis found?

A

Island of Luzon in the philipenes

51
Q

What are the ranges of dates for Homo floresiensis fossils?

A

The most recent fossils being dated 60-100,000 years old

New fossils dated 700,000 years old

No DNA recovered from either

52
Q

Homo floresiensis height

A

1-1.1 m

53
Q

Homo floresiensis brain size

A

380 cm3

54
Q

When was Homo luzonensis dated?

A

67,000 years ago

55
Q

Homo luzonensis anatomy?

A

Small teeth show poor overlap with other hominins in size and shape

Foot bone shape overlaps H.erectus

No DNA discovered so hard to test

56
Q

What is the arrival of modern humans associated with?

A

Quaternary extinction of megafauna

Fundamentals to Evolutionary Biology (19 decks)

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