EE Lecture 38: Adaptive Radiation

Question 1

why do some clades contain more species than others

Answer 1

faster speciation rate
slower extinction rate
older therefore had more time to accumulate

Question 2

how many divergences did it take to lead to 85% vertebrate diversity

Answer 2

9

Question 3

what percentage of diversity did 9 divergences take

Answer 3

85%

Question 4

in a group at a given time since its origin, what does species richness depend on

Answer 4

the balance between speciation and extinction

Question 5

give eqtn for noneqbm explanation of some clades containing more species than others

Answer 5

r = b - d

r: net diversification rate
b: speciation rate
d: extinction rate

Question 6

what does fast life history in mammals lead to

Answer 6

faster evoln and rapid speciation, plus lower extinction rates

Question 7

which selected species have faster net diversification rates

Answer 7

clades of r selected species

Question 8

do K selected species have faster diversification rates than r selected species?

Answer 8

no

predict faster net diversification rates in clades of r selected species than in clades of K selected species

Question 9

how does fast gestation affect extinction

Answer 9

fast gestations slows extinction

Question 10

what is species richness in a clade limited by

Answer 10

oportunity eg space and ecological resources

Question 11

discuss in terms of abiotic factors, why some clades have more species than others

Answer 11

groups with more species have
access to more resources - more niches
partition resources more finely -narrower niches
live in larger geographical regions

Question 12

name a fossil that shows evidence that clades diversify towards limits

Answer 12

aquatic beetle

planktonic foraminifera

Question 13

what do graphs of no.species vs. time (My) of planktonic foraminifera and aquatic beetle show?

Answer 13

that species/clades diversify towards limits

Question 14

what is adaptive radiation

Answer 14

organisms diversifing into new forms

Question 15

give some examples of adaptive radiation

Answer 15

Darwins Finches
Carribbean Anoles
Hawaiian honeycreepers
Hawaiian silverswords
Lake Baikal amphipods shrimps

Question 16

how do Darwins finches shows adaptive radiation

Answer 16

13spp

3MYA

Question 17

how do Carribean Anoles show adaptive radiation

Answer 17

c. 400 spp

Question 18

how do Hawaiian honeycreepers show adaptive radiation

Answer 18

~50 spp

~4.5MY

Question 19

how do Lake Baikal amphipods show adaptive radiation

Answer 19

~259spp

but Lake Baikal is an ancient lake = 28MYrs old

Question 20

how is adaptive radiation initiated

Answer 20

ancestor arrives by chance onto enviro empty of competitors and diversified to fill an unusual range of niches

Question 21

how do Hawaiian silverswords show adaptive radiation

Answer 21

lianes, trees, cushion plants, rosettes

28spp all within 5MY

Question 22

give an example of non-adaptive radiation

Answer 22

plethodon salamanders

Question 23

what is non-adaptive radiation

Answer 23

adapted for same niche but in different places

Question 24

what is adaptive non-radiation

Answer 24

new adaptation but then diversification

evolnary dead ended

Question 25

give an example of adaptive non-radiation

Answer 25

flying frogs new adaptive zone, morphological and behavioural innovations not a KEY innovation therefore evolnary dead ended - no diversification

Question 26

what are the steps leading to adaptive radiation

Answer 26

1. sources of ecological opportunity 2. release from natural selection 3. ecological release 4. selection/ecological speciation/character displacement 5. rapid speciation and morphological divergence 6. adaptive radiation

Question 27

what sources of ecological opportunity are there that could lead to adaptive radiation

Answer 27

key innovation new habitat antagonist extinction

Question 28

what types of ecological release is there that could lead to ecological release

Answer 28

increased trait variance density compensation broader habitat or resource use

Question 29

give details of a key innovation that could result in ecological release

Answer 29

- expanded niche space: nocturnal flight, echolocation | - partition more finely -Cichlid fish in African great lakes

Question 30

give an example of fine niche partitioning

Answer 30

Cichlid fish in African great lakes

Question 31

what is antagonist extinction

Answer 31

leaving behind - part of ecological opportunity

Question 32

what is an adaptive landscape

Answer 32

a mountain selection usually pushes pops to the top eg. mountain peak - fitness at the top ecological release fills in adaptive valleys evoln is less constrained therefore v. fast espesh with directional selection and character displacement

Question 33

what is convergence

Answer 33

repeated radiations in same adaptive zone results in convergent patterns of diversity - separate diversification into similar ecomorphs

Question 34

what does convergence provide evidence for1

Answer 34

that ecology drives diversification

Question 35

define ecomorph

Answer 35

A local variety of a species whose appearance is determined by its ecological environment

Question 36

what are vultures an example of

Answer 36

convergence

Question 37

give an example of convergence

Answer 37

vultures

Question 38

how do vultures show convergence

Answer 38

two groups of vultures, old world and new world | not especially closely related: separate origins of carrion-feeding

Question 39

what is carrion feeding

Answer 39

eating dead and decaying flesh

Question 40

what shapes diversification

Answer 40

niche differences and ecology

Question 41

how do anolis lizards shows convergent - explain

Answer 41

``` anolis lizards in the Caribbean 6 ecomorphs that are present on all 4 large islands mixture of convergent evoln and dispersal between island -crown giant -twig -grass bush -trunk crown -trunk -trunkground ```

Question 42

what do anolis lizards show

Answer 42

convergence

Question 43

where are anolis lizards found

Answer 43

in the Caribbean

Question 44

how many anolis ecomorphs are there

Answer 44

6, present on all 4 islands of the Caribbean

Question 45

name the 6 ecomorphs of anolis lizards

Answer 45

``` crown-giant twig grass-bush trunk-crown trunk trunk-ground ```

Question 46

what are the two main components of adaptive radiation

Answer 46

taxonomic diversification and ecological diversification

Question 47

what is the key factor of adaptive radiation

Answer 47

ecological release

Question 48

what may be the dominant mechanism for todays diversity

Answer 48

adaptive radiaton

Question 49

what does convergence provide strong evidence for

Answer 49

that ecology drives diversification