Lecture 2

Question 1

When did Darwin visit the Galapagos islands?

Answer 1

In 1835

Question 2

What is the first stage in Mechanisms of Speciation?

Answer 2

Some of the Finches leave the mainland and reach the island (separation)

Question 3

What is the second stage in Mechanisms of Speciation?

Answer 3

The finches reproduce and adapt to their environments (adaptation)

Question 4

What is the third stage in Mechanisms of Speciation?

Answer 4

Some finches fly to a second island (separation)

Question 5

What is the fourth stage in Mechanisms of Speciation?

Answer 5

The finches reproduced and adapted to the different environment (adaptation)

Question 6

What is the fifth stage in Mechanisms of Speciation?

Answer 6

Some finches flew back to the first island but could no longer interbreed with the finches there (division)

Question 7

What is the sixth stage in Mechanisms of Speciation?

Answer 7

This process may have occurred over and over again as the finches flew to the other islands.

Question 8

What is the name of the giant tortoises in Galapagos?

Answer 8

Geochelone Nigra

Question 9

What are the three regions in which tortoises are found?

Answer 9

Highlands, more arid regions and intermediate regions.

Question 10

What is characteristic of the highland tortoises?

Answer 10

They find their food near to the ground so their shell is dome shaped.

Question 11

What is characteristic of the more arid tortoises?

Answer 11

They look for food further off the ground so their shells are saddle shaped

Question 12

What is characteristic of the intermediate tortoises?

Answer 12

They look for food at a neither low or high level so they are in the middle of the other two types of shells.

Question 13

What are the four types of speciation?

Answer 13

Allopatric, Parapatric, Sympatric, Peripatric

Question 14

What is allopatric speciation?

Answer 14

It is also known as geographical speciation and is when biological populations of the same species become isolated so that they can no longer interbreed. It can be a result of population dispersal or geographical changes

Question 15

What is Parapatric speciation?

Answer 15

It is very rare and is when the same species are separated, not by geographical changes but by an extreme change in habitat. They can interbreed but they develop different characteristics.

Question 16

What is sympatric speciation?

Answer 16

It is when new species evolve from a single ancestral species whilst inhabiting the same geographical region. Block to gene flow within same population.

Question 17

What is peripatric speciation?

Answer 17

It is a string off allopatric speciation - It is when a small population on the edge of a larger population are isolated and prevented from interbreeding.

Question 18

Why do people have darker and lighter skin?

Answer 18

People have darker skin because they are exposed to more ultraviolet rays and therefore needed more protection, whereas people with lighter skin weren’t exposed as much. It is all to do with our need for vitamin D. Skin had to get lighter away from the tropics so that we could photosynthesise vitamin D.

Question 19

What happens to human physiques as the latitude increases?

Answer 19

It is believed that you become shorter and squatter.

Question 20

Why does being shorter and squatter help?

Answer 20

Because it reduces surface area and thereby reduces heat loss

Question 21

What is theory called that suggests physique changes?

Answer 21

Allen’s Rule

Question 22

What are the three types of bodies in Allen’s Rule?

Answer 22

Modern Eskimo and Modern Nilotic as well as the Modern pygmy and the enlarged pygmy.

Question 23

What can we infer from looking at fossil species?

Answer 23

We can compare the mythology of the fossil species with modern humans indigenous to high and low latitudes to indicate whether they lived in climates similar to that of East Africa or Arctic.

Question 24

In which climate did Neanderthals live?

Answer 24

In colder climates

Question 25

In which climate did the homoerectus live?

Answer 25

In warmer climates

Question 26

What are the three vitamins humans cannot live without but do not produce themselves so have to obtain from diet?

Answer 26

Vitamin D, N-3 Fatty Acids Iodine and B vitamins

Question 27

What do we get Vitamin D from?

Answer 27

Fruit and veg

Question 28

What do we get fatty acids from?

Answer 28

From fish

Question 29

What do we get B vitamins from?

Answer 29

From red meat

Question 30

What does our need for these three vitamins tell us about our ancestors?

Answer 30

That at one point in time, we had such a huge amount of these vitamins in our diets that we didn’t have to produce them ourselves.

Question 31

What is the Savannah theory?

Answer 31

This is when the jungles and rain-forests became overpopulated or diminished in size and so the human predecessors had to leave and live on the open plain or savannahs. They had to hunt game for food so they learnt to stand on their hind legs to be able to see more easily. Because it was so hot out there, they had to shed their hair so that sweat could flow freely. Speech and communication developed from hunting and living in packs.

Question 32

What is the problem with the Savannah theory?

Answer 32

It leaves out the intermediate stage which was a water-born time.

Question 33

What is the intermediate stage?

Answer 33

It was a water-born time when we learnt to live in and out of the water - we are bipedal meaning that our spine and limbs are on the same plain.

Question 34

What is interesting about being bipedal?

Answer 34

Bipedal is a non-primate typical feature of homosapiens

Question 35

What are the physical features that act as evidence of the waterside theory?

Answer 35

Hair thickening prior to parturition
Body fat/weight ratio
Buttocks
Breasts
Fleshy nose
Paranasal sinuses
Apocrine gland reduction armpit and pubic regions
Eccrine gland increase
Webbing between fingers and toes

Question 36

What are the pyschological features that act as evidence of the waterside theory?

Answer 36

Innate ability to swim at 4 months
Grasping reflex at 6 months
Phobias?

Question 37

How does the waterside theory contribute to bipediality?

Answer 37

It is suggested that it is in water that humans learnt to stand on their hind legs - with the water carrying the body weight and taking the strain off the muscles

Question 38

Are chimpanzees or bonobos less fearful of water?

Answer 38

Bonobos

Question 39

Does the willingness to enter the water explain how fish and not just shellfish came to be eaten?

Answer 39

No

Question 40

What explains the high fish content of our diets?

Answer 40

The fact there was a long period of flooding followed by a period of climatic instability that produced a flood/drought cycle. As a result, the former flooded areas dried up in the drought. The fish that were in these flooded areas congregate in shallow water and then when that is gone, they bury themselves in the mud. Therefore, they are right on the surface and so easy for our predecessors to access. The cycle was eventually broken and drought conditions remained so the rainforest areas became savannah areas so the species remaining had to adapt to these new conditions.

Question 41

What other species show adaptations to wetland areas?

Answer 41

Elephants, Hippopotamus, Rhinocerous.