Mammals

Question 1

About how many species of mammals are there?

Answer 1

~5000

Question 2

What are the 3 unique features of mammals?

Answer 2

1. hair
2. sweat glands
3. mammary glands

Question 3

Which evolved first, mammals or birds?

Answer 3

Mammals!

Question 4

About how many years ago did mammals evolve? And phylogenically, are they more related to amphibians or reptiles?

Answer 4

During carboniferous period, about 350 MYA.
They’re closer to reptiles.
First the amphibians split off from the amniota, then the amniota split into reptiles & mammals.

Question 5

Skull morphology is really important for distinguishing amniotes. Describe the 3 extant skull types and the 1 extinct one.

Answer 5

1. Anapsids (no hole - turtles)
2. Synapsids (one big hole - mammals, therapsids)
3. Diapsids (2 holes, dinos & birds)
4. EXTINCT Euryapsids (marine reptiles)

Question 6

What is the difference between the jaw bones of reptiles & mammals?

Answer 6

Reptiles have lots of jaw bones, in mammals some of these bones have migrated up to form mammalian middle-ears.

Question 7

What allowed mammals to radiate & diversify?

Answer 7

Dinos going extinct, allowed mammals to fill now-empty niches & return to ocean.

Question 8

What is the ancestor of whales?

Answer 8

“Ambulocetus”

Question 9

What was the megatherium?

Answer 9

A giant ground sloth, herbivorous, elephant-sized.

Question 10

Why did smilodon & megatherium go extinct?

Answer 10

Human hunting.

Question 11

What are the 3 groups of mammals?

Answer 11

1. Prototherians (egg laying, platypus, echidna)
2. Marsupials (pouch development)
3. Eutherians (placental)

Question 12

Do marsupials have a placenta?

Answer 12

Yes they can, so it’s not only the eutherians that have placentas.

Question 13

How do fetuses get nutrition/oxygen from the mom? What kind of veins/arteries carry these to/from the mom?

Answer 13

Diffusion - no direct blood mixing.

Two arteries carry deoxygenated blood back to the mother, whereas a vein carries fresh blood towards the fetus.

Question 14

How does the fetal heart adapt quickly to independent circulation once the baby is born?

Answer 14

Aortic holes close up.

Question 15

What are the 2 groups of primates?

Answer 15

• Prosimians (arboreal & nocturnal - lemur, loris. only Madagascar & SE-Asia)
• Anthropoids

Question 16

Is the tarsier a prosimian or an anthropoid?

Answer 16

Anthropoid.

Question 17

What is the diff between old-world & new world monkeys?

Answer 17

Old world: Africa, Asia, Indonesia
NO prehensile tail. (ex. baboons, vervets)

New world: Where humans colonized, Americas.
Prehensile tail, flat noses, arboreal. (ex. capuchins, vervets)

Question 18

What’s the diff between monkeys & apes?

Answer 18

Apes have a larger brain to body size ratio (bigger brains)

Question 19

Which are bigger, gibbons or apes?

Answer 19

Apes.

Question 20

Which came approximately first, ardipethecus or australopithecus?

Answer 20

Ardipithecus.

Question 21

What came first, modern big brain size or bipedalism?

Answer 21

Bipedalism.

Question 22

What type of hominid was Lucy?

Answer 22

Australopithecus.

Question 23

When did hominids begin to use tools?

Answer 23

~ 2 MYA

Question 24

What was remarkable about homo erectus, aside from standing up?

Answer 24

Around 1.6 MYA, left Africa, first used fire.

Question 25

Who had bigger brains, Sapiens or Neanderthalensis?

Answer 25

Neanderthalensis!

Question 26

How much of non-Africans' DNA is neanderthal?

Answer 26

1.5-2.1%

Question 27

What's special about Homo floresiensis?

Answer 27

Survived until 17k years ago, probably extinct because of volcanic eruption. Were like dwarf humans, very small.

Question 28

Which humunculus has genitals, the somatosensory or the motor?

Answer 28

Only the somatosensory.

Question 29

London taxi driver study - what area of the hippocampus was enlarged?

Answer 29

Mid-posterior.

Question 30

Does the amygdala encode acoustic features of stimulus or its affective valence?

Answer 30

Both!

Question 31

What are the 5 mechanisms of evolution?

Answer 31

1. Mutation 2. Random genetic drift 3. Natural selection (survival of the fittest) 4. Sexual selection (reproductive success) 5. Stabilizing Gene flow between individuals.

Question 32

What are the 2 types of sexual selection?

Answer 32

1. Intra-sexual (competition) | 2. Inter-sexual (female's choice)

Question 33

What are the 3 major "species concepts", in other words, 3 major ways of distinguishing species?

Answer 33

1. Typological (as per morphology) 2. Biological (look at interbreeding ability) 3. Phylogenetic (evolutionarily separate or not)

Question 34

What's the main problem with typological speciation?

Answer 34

Major gender differences in morphology, major adult/young differences in morphology. Also within-species morphological differences (think of dogs!!)

Question 35

What's the main problem with the phylogenetic species concept?

Answer 35

Can't be used for fossils, need DNA. Only reflects time, not reproductive barriers

Question 36

What is the problem with the biological species concept?

Answer 36

Difficult for allopatric populations (pops that split because of being physically apart), not clear whether they're different species or if they were put back together they'd rebecome one. Not useful for fossils.

Question 37

What are the 7 mechanisms of speciation?

Answer 37

1. Uniform natural selection 2. Divergent natural selection/ecological speciation 3. Genetic drift 4. Polyploidy 5. Hybridization 6. Sexual selection (attractiveness and conflict) 7. Cytoplasmic incompatibility (differing microbiome)

Question 38

What's the diff between population ecology & community ecology?

Answer 38

``` Population = study of demographics (births, deaths) Community = study of interactions between species ```

Question 39

What does "inclusive fitness" refer to?

Answer 39

Individuals helping their kin reproduce at their own expense because they're still passing on genes they share.

Question 40

What is the Allee effect?

Answer 40

High abundance of a species increases chances of reproductive success and vice versa

Question 41

What study was the beginning of community ecology?

Answer 41

The lynx & hare study looking at the population of hares when put in an environment with food + predators or food + no predators or no predator + no extra food