Coevolution

Question 1

Define coevolution

Answer 1

When two or more species reciprocally affecting each others evolution

• Species that depend on each other,
  or that are linked ecologically, are
  likely to influence each other’s evolutionary trajectory.

Question 2

Define coadaptation

Answer 2

• Mutual adaptation of species, which may come to depend on each other.
• Coadaptation suggests, but is not conclusive evidence for, coevolution.

Question 3

What does coevolution require

Answer 3

Coevolution requires shared history and mutual involvement in the origin
of the adaptations.
i.e. multiple cycles of mutual effects, not just one-time adaptation

Question 4

What 4 cases may coevolution occur in

Answer 4

Mutualism and symbiosis (Reciprocal)

Predation and parasitism (Antagonistic)

Question 5

If the interactions are antagonistic then what is the process of coevolution called

Answer 5

• it is called an evolutionary arms race
• the adaptations are then weapons or defenses

Question 6

Describe proving coevolution

Answer 6

• coevolution means two separate lineages mutually influence each others evolution
• the two lineages tend to change together and speciate together
• long term co evolution should lead to similar phylogenetic histories. speciation in one leads to speciation in the other

Question 7

Examples of coadaptations in mutualism

Answer 7

• Ant formica fusca and caterpillar glaucopsyche lygdamus
• pitcher plants
• ant guarded acacias

Question 8

Describe escape and radiation as evidence for coevolution

Answer 8

• is an Idealized example of hostplant and herbivore coevolution,
  showing multiple cycles of mutual effects of escape
  and radiation in antagonistic coevolution

Question 9

What is the relationship between coevolution and biogeography

Answer 9

• The study of coevolution and biogeography originated
  at the same time in the history of biology, and from the
  contributions of the same group of people.

–> Henry Walter Bates was the major figure in coevolution and biogeography

Question 10

Is mimicry an example of coevolution

Answer 10

Yes

Question 11

Describe batesian mimicry

Answer 11

One non-poisonous or non-distasteful species mimics
another poisonous or distasteful species.

Question 12

Describe mullerian mimicry

Answer 12

Two poisonous or distasteful species evolve to look like
each other. The advantage to each species is that a
proportion of the sacrifice (mortality due to failed
predation) in educating predators is shared with the
other species.

Question 13

What is an example of mullerian mimicry

Answer 13

Heliconius eratio and Heliconius melpomene

–> Individuals of different species
within one locality look more
similar than geographically
separated individuals of the
same species.
H. erato and H. melpomene are only
distantly related to each other within
their genus:

Question 14

What is fahrenholz’s rule

Answer 14

Common ancestors of present day
parasites were themselves parasites of
common ancestors of present day hosts.

–> parasitism is another arena for covolution

Question 15

What are the parallels between parasitism and biogeography

Answer 15

• Hosts are areas of distribution of parasites, which are often confined or
  ‘endemic’ to their specific hosts.
• Parasite-host associations are subject to “vicariance” (speciation of host),
  “dispersal” (host shifts), and extinction.
• The analytical approaches used in biogeography are useful in
  reconstructing the evolution of host-parasite relationships.

Question 16

What was Daniel Brooks hypothesis

Answer 16

• Analysis of the phylogenetic relationships of parasites provides
  direct evidence of the relationships among the hosts.
• Parasite distributions on hosts can be used to reconstruct the
  host species’ phylogeny.

Question 17

What are the problems with Daniel Brooks hypothesis

Answer 17

Now considered too ambitious/optimistic
* Some hosts may have no parasites, the equivalent in biogeography of
certain taxa being absent from certain areas. Absence can be primary
(isolation), or secondary (extinction).
* Some parasites may occur on more than one host, the equivalent in
biogeography of widely distributed taxa.
* Some hosts have more than one closely related parasite (duplication),
the equivalent in biogeography of overlapping distributions.

Question 18

What is an example of coevolution in parasites

Answer 18

seals and their lice
pocket gopher and lice

Question 19

What is duplication in terms of parasites

Answer 19

more than one parasite lineage in a single host.

Question 20

What is co-speciation

Answer 20

corresponding speciation events (‘vicariance’)

Question 21

What is a sorting event

Answer 21

usually extinction of a parasite from a host species

Question 22

What is a host switch

Answer 22

horizontal transfer (‘dispersal’)

Question 23

Why might phylogenies of parasites not always match host phylogenies

Answer 23

• differential extinction in lineages of various parasite species may lead to disagreement in their phylogenetic trees
• so parasites might infest only some individuals in a population, or only some parts of the geographic range of the host
• thus phylogenies of parasites may not always match host phylogenies

Question 24

Fahrenholz’s rule and Brooks hypothesis are more likely to be true in what cases

Answer 24

• in cases of endosymbiosis

Question 25

What is the test for introgression

Answer 25

the ABBA/BABA test

Question 26

READ OF ABBA BABA TEST SLIDE AT THE END OF THE DECK