Lecture 8 - Adaptive Radiations In Relation To Food Acquisition

Question 0

How did ‘Darwin’s finches’ evolve?

Answer 0

It is believed that granivorous grassquit finches strayed onto the galapogas islands. They had no competition here and evolved into a variety of different insectivores due to the diversity of insects on the islands. In some granivory re-evolved

Question 1

Give the definition of an adaptive radiation

Answer 1

The evolution of ecological and phenotypic diversity within a rapidly multiplying lineage
OR
The rapid evolution from a common ancestor of several species that occupy different ecological niches

Question 2

What were the two lineages of eutherian mammals present at the end of the Cretaceous period?

Answer 2

Protoeutheria - an insectivore like group

Condylarthra - a hoofed group

Question 3

What are the three major mammalian groups?

Answer 3

Monotremes
Marsupials
Placental mammals

Question 4

Give an example of a monotreme

Answer 4

The echidna which is an insectivore living in Australasia

Question 5

Give an example of a marsupial

Answer 5

Red kangaroo

Question 6

Give an example of a placental mammal

Answer 6

Ursus maritimus

Question 7

How are placental mammals classified again?

Answer 7

By feeding type:
Herbivores -gnawing, grazers and browzers
Omnivory
Carnivory

Question 8

Give an example of a gnawing herbivore

Answer 8

Naked mole rat

Question 9

Give an example of a grazer

Answer 9

Cattle

Question 10

Give an example of a browser

Answer 10

Deerw

Question 11

How are walruses specialised?

Answer 11

They are mollusc specialists which have adapted with elongated canines for making holes in the ice

Question 12

Name a plankton specialist

Answer 12

Baleen whales

Question 13

Give an example of an extreme insectivore specialist

Answer 13

Giant ant eater which only eats termites

Question 14

Why did the saber toothed cat die out?

Answer 14

It became overspecialised leading to an evolutionary dead end. Due to it’s tendency to prey upon slow moving megafauna it adapted two dagger like canines with a gape up to 180 degrees leading to small bite pressure meaning that as the herbivorous megafauna died out they were unable to feed on smaller mammals

Question 15

What is the definition of a niche?

Answer 15

The part of the environment thaf is used by organisms

Question 16

What are the different environment niches?

Answer 16

Fossorial
Semi-fossorial
Aquatic
Semi-aquatic
Volant
Scansoria
Arboreal

Question 17

What is gumivory?

Answer 17

Where an animal feeds on gum or tree sap

Question 18

What is a myrmecophage?

Answer 18

An organism specialised for eating ants and termites

Question 19

What is a frugivore?

Answer 19

A fruit eater

Question 20

What is a sanguivore?

Answer 20

A blood feeder

Question 21

What are the feeding adaptations of the spotted hyena?

Answer 21

Great strength per unit area
Muscle wraps underneath the jaw
Enormous bite strength
Huge canines

Question 22

What is the feeding specialisation of a giraffe?

Answer 22

No canines mostly molars

Question 23

What is type of teeth do horses have?

Answer 23

Hypsodonts

Question 24

What teeth do hippos have?

Answer 24

Brachydonts

Question 25

In how many fish species have at least 2 trophic morphs been found?

Answer 25

About 100

Question 26

How does colouration evolve?

Answer 26

It can evolve rapidly in response to sexual selection

Question 27

How is lake surface area tied to the number of species?

Answer 27

It has an exponential relationship with the number of species present

Question 28

What is the relationship between the age of an adaptive radiation and the number of species present?

Answer 28

Negative relationship between residual number of species and age of adaptive radiation

Question 29

How does an adaptive radiation develop?

Answer 29

It explodes then slows down

Question 30

What is special about the Arctic Char?

Answer 30

It has a variety of different genetically true trophs within the same lake, pescivorous large benthic, planktivorous and dwarf

Question 31

What is special about the threespine stickleback?

Answer 31

There are many different morphs for it across the world

Question 32

Where do benthic limnetic pairs of three spine sticklebacks occur and why?

Answer 32

In the Canadian great lakes due to allopatric speciation

Question 33

What are the main features of the limnetic morph of three spine stickleback?

Answer 33

Large eyes
Narrow body
Gill rakers are long and numerous

Question 34

What are the features of a benthic threespine stickleback?

Answer 34

They have small eyes, wide mouths and gill rakers which are short and few

Question 35

What is sympatric speciation?

Answer 35

Speciation through competition for limited food

Question 36

What is allopatric speciation?

Answer 36

Speciation by way of double invasion

Question 37

What happened in Lake Washington with three spine sticklebacks?

Answer 37

In the 1950s it mainly had low plated three spine sticklebacks common with freshwater lakes. However later they found that they seemed to have reverted back to their marine fully plated form and increased on size. This is believed to be due to the Lake being cleaned up in the early 70s leading to an improvement in water clarity therefore they needed more protection from cutthroat trouts.