18. Our Origins

Question 1

How many living species is the hominid genus comprised of ?

Answer 1

8

Question 2

When did humans leave Africa? (according to oppenheimer)

Answer 2

Approx 72,000 years ago

Question 3

Where did humans first spread after Africa?

Answer 3

Around the Indian ocean toward Australasia

Question 4

What is phylogeography?

Answer 4

Studying human genetic differences to track the paths humans have taken

Question 5

What is the ‘Beachcomber route’?

Answer 5

A proposed dispersal route suggesting humans used a coastal route to spread

Question 6

During what range of times did Neanderthals live? And where?

Answer 6

250,000-40,000 Years ago

Question 7

When did Neanderthals and Humans interbreed?

Answer 7

60,000-40,000 years ago

Question 8

What examples of species are included in the category of LHVs?

Answer 8

ground sloths, giant kangaroo, moa, woolly mammoths, straight tusked elephants, steppe rhino, woolly rhino, giant deer etc etc

Question 9

What environmental hazard was subdued by the presence of LHVs and why?

Answer 9

Forest fires, as LHVs cropped vegetation and maintained large open spaces

Question 10

When did LHVs go extinct?

Answer 10

In a megafaunal extinction when human’s arrived

Question 11

What are the two broad possibilities for LHV extinction? Which one is likely?

Answer 11

Human effect or environmental change
- Human effect most likely.

Question 12

Why is it harder to be definite about reasons for LHV extinction on continents than on oceanic islands?

Answer 12

On continents it’s harder to disentangle the effects of humans from the effects of climate change at the time

Question 13

Why does Africa have such a different distribution of animal sizes to any other continent?

Answer 13

Africa is where humans evolved so its likely that since LHVs evolved alongside humans, they were able to coexist

Question 14

What are 3 bioanachronisms from the era of LHVs?

Answer 14

Un-distributed fruits, defensive trees, and wet tundra regions

Question 15

Explain how undistributed fruits are a hangover from LHVs?

Answer 15

Trees in regions that used to have LHVs sometimes produce fruits where seeds would have been distributed by LHVs but now rot in place under the trees

Question 16

What are some examples of undistributed fruits due to lack of LHVs?

Answer 16

Papaya, avocado

Question 17

How do plants with defence mechanisms relate to now extinct LHVs?

Answer 17

Some trees/plants have defence mechanisms that are unnecessary in relation to current animals but theoretically would’ve protected the plants from extinct LHVs

Question 18

Give two examples of extinct animals that plants still have defence mechanisms for.

Answer 18

Some trees have ‘wire plant syndrome which could have protected against giant ground sloths - which are predicted to have gripped tree trunks while feeding.

Some ground shrubs have protection against now extinct large birds.

Question 19

What sort of conditions did LHVs maintain in tundra reasons and how?

Answer 19

Plaid-like vegetation patterns
- more mixed diets promoted greater diversity within local flora

Question 20

What effect did plaid like vegetation patterns have on water in tundra regions?

Answer 20

The greater diversity returned water to the atmosphere more effectively.

Question 21

Which species subject to the island rule have greater extinction risks, giants or dwarfs?

Answer 21

Those that underwent gigantism

Question 22

Do species that underwent changes in line with the island rule have greater or lower extinction risks than those that don’t?

Answer 22

Greater, specifically ones whose mass have changed by 4-10 times