ch 13- evolution

Question 1

polytomy/ multifurcation

Answer 1

an internal node of a
phylogenetic tree that leads to more than two tips.

Question 2

parsimony

Answer 2

means the simpler the evolutionary
explanation, the better. Phylogenetic trees
minimizing evolutionary reversals, convergent evolution and parallel evolution are preferred.

Question 3

anagenesis

Answer 3

describes the gradual evolution of an
interbreeding population without splitting.

Question 4

cladogenesis

Answer 4

refers to the splitting apart of
evolutionary lineages (formation of new clades).

Question 5

internal node

Answer 5

An internal node is a branch point on a cladogram, and represents the splitting (divergence) of a single group into two descendant groups.

Question 6

cladogram

Answer 6

type of phylogenetic tree that
shows such inferred evolutionary relationships
among various biological species.

Question 7

monophyletic vs paraphyletic

Answer 7

Phylogenetic trees can either be monophyletic (an
ancestor and all its descendants) or paraphyletic
(ancestor and some but not all of its descendants).

Question 8

phylogenic tree

Answer 8

A phylogenetic tree is a branched diagram that shows inferred evolutionary relationships between different taxa.

Question 9

clade

Answer 9

cluster with an ancestor and all its descendants.

Question 10

batesian mimicry

Answer 10

a non-harmful muanimal resembles a harmful one.

Question 11

mullerian mimicry

Answer 11

two poisonous animals resemble each other to warn their predator.

Question 12

aposematic coloration

Answer 12

(warning coloration): Vibrant coloration in poisonous animals to warn predators.

Question 13

crypsis

Answer 13

Similar to camouflage, except
includes olfactory (smell) or auditory
methods of concealment (ex. scent masking, silencing).

Question 14

camouflage

Answer 14

(cryptic coloration): Match
appearance to environment to avoid
detection. Strictly visual method of
concealment.

Question 15

coevolution

Answer 15

Two species impart selective
pressure on each other. Classic examples are
hummingbirds and flowers.

Question 16

parallel evolution

Answer 16

Species diverge from a
common ancestor but undergo similar changes.

Question 17

convergent evolution- homoplasy

Answer 17

Unrelated species adapt to similar environments becoming
more alike (analogous structures).

Question 18

divergent evolution

Answer 18

Species diverge from common ancestor.

Question 19

sympatric speciation

Answer 19

Occurs without a
geographical barrier.

balanced polymorphism
polyploidy
hybridization

Question 20

hybridization

Answer 20

Some hybrids are more fit
than purebreds.ol

Question 21

polyploidy

Answer 21

In plants results from
nondisjunction during meiosis. (e.g., two 3n
organisms, usually sterile, meet and are
reproductively compatible).

Question 22

balanced polymphormism

Answer 22

polymorphism: Different phenotypes are isolated within the same
area.

Question 23

allopatric speciation

Answer 23

Occurs due to a
geographical barrier.

Question 24

adaptive radiation

Answer 24

Occurs when many species arise from one ancestor as they adapt differently to their environments. During adaptive radiation, species can specialize to fill different niches within the same environment.

Question 25

phyletic graduation

Answer 25

Evolution happened
gradually via accumulation of small intermediary
changes. Not likely to be true (not supported by
fossil evidence).

Question 26

punctuated equilibrium

Answer 26

Short spurts of
evolutionary changes during periods of stasis
(supported by fossil evidence).

Question 27

speciation

Answer 27

is how species form, starting with
reproductive isolation, which leads to interruption
of gene flow between populations that gradually
develop into two species.

Question 28

postzygotic isolation types

Answer 28

refers to barriers to
organism success after zygote has formed.

hybrid motality (inviability)
hybrid sterility
hybrid F2 breakdown: Hybrid F2 generation have reduced fitness compared to their parental generation.

Question 29

prezygotic isolation

Answer 29

habitat isolation
temporal isolation
behavioural isolation
mechanical isolation
gamete isolation (incompatibility)

Question 30

macroevolution

Answer 30

is long-term and occurs at a level at
or higher than species. Species are reproductively
isolated (via prezygotic and postzygotic isolating
mechanisms) resulting in a lack of gene flow between
species.

Question 31

what are the factors causing microevolution

Answer 31

is the process when gene
frequencies change within a population over
generations (favorable genes increase, unfavorable
decrease).

Question 32

what are the factors causing microevolution

Answer 32

genetic drift
non random mating
mutations
natural selection
gene flow: migration- non random moving alleles between populations leading to variation through mixing

Question 33

genetic drift

Answer 33

Allele frequencies change by
chance. Larger effects on small populations.
● Bottleneck effect: Smaller gene pool, some
alleles may be lost (eg. disaster killing
majority of population).
● Founder effect: Some individuals migrate
away from the population.

Question 34

sources of genetic variation

Answer 34

mutation
sexual reproduction
balanced polymorphism
polyploidy

Question 35

balanced polymorphism

Answer 35

Maintains a variety of
phenotypes within a population.
● Heterozygote advantage (e.g., sickle cell
anemia): Two parents produce an offspring
that is more fit than either parent.
● Minority advantage: Rare phenotypes offer
higher fitness. Cycle between high and low
frequency (e.g., advantageous against
hunters’ search images).
● Neutral variations: May become beneficial
if the environment changes.

Question 36

polyploidy

Answer 36

Plants have multiple copies of alleles
introducing more variety and preserving
different alleles. Can also mask effects of a harmful recessive allele.

Question 37

paleontology

Answer 37

is the study of fossils through
actual remains of the animal or their traces (ichnofossils). Petrification is the process by which living organisms turn into fossils. These fossils allow us to see the development of
species through time by comparing deepest
(oldest) fossils to shallowest (youngest).

Question 38

what do chordates have during development

Answer 38

gill slits

Question 39

homologous structures

Answer 39

may or may not
perform the same function but have a
common ancestor. eg. forearm of bird and
forearm of human.

Question 40

analogous structures

Answer 40

same function, do not
have a common ancestor, e.g. bird wings and
bat wings.

Question 41

vestigial structures

Answer 41

serve no purpose but
are homologous to functional structures in
other organisms, e.g. human appendix and
cow cecum.

Question 42

cuvier

Answer 42

proposed catastrophism. Catastrophes
lead to mass extinctions of species in those areas. The different populations in different areas were shaped by what catastrophes had occurred, and what random organisms

Question 43

lamrach

Answer 43

● Use and disuse: used body parts will develop and unused ones are weakened, leading to evolution.
● Inheritance of acquired traits: traits
acquired through use and disuse are passed onto offspring (eg. giraffe stretching neck will cause its neck to develop, and produce long
necked offspring). This is incorrect - acquired characteristics are generally not heritable.

Question 44

darwin

Answer 44

theory of natural selection

Natural selection is the gradual, non-random process where allele frequencies change as a result of environmental interaction. Survival of the fittest
occurs as individuals with greatest fitness (ability to survive and produce viable and fertile offspring) have greatest success, and pass on more DNA to future generations compared to less fit parents.
Leads to the evolution of the population (not individuals).

Question 45

what are the requirements for natural selection

Answer 45

1. Demand for resources exceeds supply: results in
   competition for survival (fittest survive to pass
   on genes).
2. Difference in levels of fitness due to variation in
   traits: differentiate ability to compete and
   survive (e.g., black peppered moths favored over
   white moths during Industrial Revolution).
3. Variation in traits must be genetically-
   influenced (heritable) to be passed onto

offspring.
4. Variation in traits must be significant for
reproduction and/or survival: genes improving
reproductive success/survival are favored and
increase over generations and vice versa.

.

Question 46

types of natural selection

Answer 46

1. Stabilizing selection: Mainstream (average) is
   favored (e.g., birth weight). Diagram follows a
   standard bell curve.
2. Directional selection: One extreme favored (e.g.,
   longest giraffe neck allows access to the most
   leaves).
3. Disruptive selection: Rare traits favored,
   mainstream is not (e.g., snails living in low and
   high vegetation areas).

Question 47

artificial selection

Answer 47

Carried out by humans to
selectively breed for specific traits (e.g., dog breeding).

Question 48

hardy weinberg formula

Answer 48

calculates genetic
frequency during genetic equilibrium (no change in
gene frequencies). If both equations hold true, the
population is under Hardy-Weinberg equilibrium.

p+1=1
p^2+ 2pq + q^2= 1