Ch. 15

Question 1

Hutchinson’s view: ecology…

Answer 1

provides the selective environment within which evolution acts.

Question 2

At the time ecologists viewed evolutionary processes occurring over long time periods and
thus contemporary evolution could not influence population dynamics or outcomes.

We now know that this isn’t entirely true for two reasons:

Answer 2

Evolution can occur over very short time scales.

High degree of interplay between ecological and evolutionary forces that result in
eco-evolutionary feedbacks.

Question 3

community phylogenetics:

Answer 3

a field that examines community ecology
from a phylogenetic perspective.

Question 4

What is an eco-evolutionary dynamic?

Answer 4

“The cyclical interaction between ecology and evolution such that changes in ecological
interactions drive evolutionary change in organismal traits that, in turn, alter the form of
ecological interactions.”

Question 5

Theory suggest that alterations in prey vulnerability will affect

Answer 5

predator-prey interactions
and cycling.

Question 6

Trade-offs may occur that may also influence predator-prey cycling. ex.?

Answer 6

If a trait reduces vulnerability to predation, it might come at a cost of reduced population growth
for prey populations.

Question 7

Hairston et al.
developed an experimental system to test this idea ( trade offs of trait and populaiton size) using
freshwater plankton.

Answer 7

Phytoplankton can evolve traits that reduce their susceptibility to
predation by zooplankton such as:

Spines, toxic chemicals, gelatinous coatings, increased size

Question 8

Chlamydomonas ( Plankton) with trait trade offs

Answer 8

usually is biflagellated, but when zooplankton
populations are present in high quantities Chlamydomonas can clump
into colonies (unflagellated) and become too large for rotifers to eat

There is a cost though, clumping Chlamydomonas has a lower resource
competitive ability when compared to bilagellated Chlamydomonas.

Question 9

If low genetic diversity started in the population….

if high genetic diversity oscillatory dynamics resulted
with dominant algal genotypes….

Answer 9

If low genetic diversity started in the population, there was directional selection towards one,
moderately well-defended genotypes;

if high genetic diversity oscillatory dynamics resulted
with dominant algal genotypes alternative over time between well-defended large colonies
and small colonies or single cells.

Question 10

phylogeny.

Answer 10

We can examine evolutionary (historical) relationships between extant species by creating a phylogeny

A phylogeny describes the hypothesized pattern of evolutionary relationships among a set of
organisms.

Question 11

phylogeny or phylogenetic trees infer evolutionary relationships based on

Answer 11

descent from a common ancestor.

Question 12

A phylogenetic node represents a

Answer 12

a taxonomic unit

Question 13

terminal nodes vs internal nodes

Answer 13

terminal nodes are existing taxa, internal nodes
represent shared ancestors.

Question 14

branch length could have no meaning or represent

Answer 14

amount of time diverged between species (molecular
clocks),

Question 15

A monophyletic lineage is one that includes

Answer 15

one common ancestor and all of its descendants
and that entire group is called a clade.

Question 15

phylogenetic outgroup

Answer 15

a distantly related taxon – this helps to establish the group’s
common ancestor or root)

Question 16

Two species that originate from the same ancestor are called

Answer 16

sister taxa

Question 17

Phylogenetic effects

Answer 17

strong phenotypic similarity among closely related species.

Question 18

The competitive-relatedness hypothesis or phylogenetic limiting similarity hypothesis

Answer 18

If species with similar traits, use similar resources, and in similar habitats then one would
expect to observe strong interspecific competition and this would lead to very few similar
species inhabiting one ecosystem.

Question 19

Alternatively, species might be ecologically limited to specific sets of characteristics and as
a result might undergo

Answer 19

habitat filtering

Question 20

habitat filtering,

Answer 20

more
similar species inhabiting particular communities than by chance.

Question 21

Phylogenetic Overdispersion

Answer 21

If strong interspecific competition
determines species coexistence

Species are more evenly dispersed in
phylogenetic space than would occur by
chance

This data would support the
competitive-relatedness
hypothesis/phylogenetic limiting similarity
hypothesis

Question 22

Phylogenetic Clustering

Answer 22

Closely related species share similar
environmental requirements

Communities contain more closely related
species than would occur by chance

This data would support the habitat filtering
hypothesis

Question 23

Conserved =

Answer 23

= traits that are
ancestral in origin

Question 24

Convergent =

Answer 24

traits that are similar due to similar
environmental circumstances.

Question 25

ARE CLOSER RELATED
SPECIES STRONGER COMPETITORS?

Answer 25

Tests of the competitive-relatedness hypothesis have yielded mixed results.

Few direct tests of the assumption that closely related species are stronger competitors than
distantly related species.

Question 26

DOES PHYLOGENETIC
OVERDISPERSION OCCUR?

Answer 26

Significant phylogenetic overdispersion is rare, which is surprising given the strong effects
of interspecific competition.

But, an interesting result: Graham et al. (2009) analyzed spatial distribution of communities
that fell in the top 10th percent for dispersion vs. the lowest 10th percent (clumped).

Question 27

where did Graham find phylogenetically dispersed and cluster communites

Answer 27

Graham et al. (2009) found that phylogenetically dispersed communities were found in most
lowlands; phylogenetically clustering occurred in harsh environments.

Question 28

harsh environments =

Answer 28

stronger environmental filter = phylogenetic clustering.

Question 29

the first person to draw a phylogenetic tree

Answer 29

Darwin - on the orgin of species

Question 30

The competitive-relatedness hypothesis or phylogenetic limiting similarity hypothesis
predicts

Answer 30

strong interspecific competition and high overdispersion of highly related species.

Question 31

The habitat filtering hypothesis or phylogenetic clustering hypothesis predicts

Answer 31

that
closely related species would be clustered due to sharing similar environmental
requirements.

Question 32

The evidence for competitive-relatedness hypothesis is

Answer 32

MIXED

Question 33

there is strong evidence
for

Answer 33

habitat filtering particularly in harsh environments.