evolution

Question 1

SIMPLE evolution definition

Answer 1

Descent with modification

Question 2

NUANCED evolution definition

Answer 2

A change in gene frequency
within a population over many generations
that confers a fitness advantage

Question 3

what does DNA methylation do to gene expression. (epigenetics)

Answer 3

DNA methylation = represses expression
DNA methylation can decrease gene expression → stress can alter methylation of some DNA → the effects of stress can be ‘passed on’, altering the physiological and innate behavioral responses of offspring (epigenetics)

Question 4

Natural selection definition

Answer 4

the process by which individuals within a population possess
certain traits, and by having these traits tend to survive and reproduce more often

Question 5

how short can evolution be? (timeline)

Answer 5

Darwin’s ideas of evolution require “deep time” (millions of years), but we know it can happen in far
more observable timescales.

Question 6

what are the 3 conditions required for evolution by natural selection

Answer 6

1. Variation in a traits
2. Traits must be heritable
3. Traits must impact fitness

Question 7

what are the four lines of evidence for evolution

Answer 7

1. Homology
2. Direct observations
3. The fossil record
4. Biogeography

Question 8

what is homology

Answer 8

Similarity in structure, function, genetics
Result: related species can have similar characteristics, yet function can vary

Question 9

what is the difference between homologous and analogous structures?

Answer 9

-Homologous structures: similar in structure because of common ancestry, but not necessarily in function.
-Analogous structures: which are similar in function, but with a different evolutionary origin

Question 10

Vestigial structures definition

Answer 10

remnants of features that
served a function in the organism’s ancestors

Question 11

what are Conserved physiological processes

Answer 11

similar pathways and responses
because of common ancestry

Question 12

what are pseudogenes

Answer 12

genes that remain in the genome but have lost at least some functionality

Question 13

fossil records provide evidence of what ?(3)

Answer 13

▪ The origin of new species
▪ The extinction of species
▪ Changes over time

Question 14

biogeography definition

Answer 14

the study of the geographic distribution of species.
(ex. make predictions based on Pangaea on where similar species should be found)

Question 15

true or false : Distribution of fossils and living groups reflects historic movement of continents.

Answer 15

true

Question 16

what are endemic species

Answer 16

endemic species are species not found anywhere else in world

Question 17

what are the three modes of natural selection

Answer 17

1. Directional selection
2. Disruptive selection
3. Stabilizing selection

Question 18

what is directional selection

Answer 18

pushes a population in one direction

Question 19

what is disruptive selection

Answer 19

pushes a population in two direction

Question 20

what is stabilizing selection

Answer 20

maintains the norm

Question 21

name all the mechanisms of evolution (5)

Answer 21

▪ Natural selection
▪ Artificial selection
▪ Genetic drift (chance events)
▪ Gene flow (transfer of genes between populations)
▪ Mutations

Question 22

artificial selection

Answer 22

The selective breeding of
plants and animals to
encourage the occurrence of
desired traits; over time this
can lead to domestication

Question 23

explain genetic drift

Answer 23

-Changes in allele frequencies across generations due to chance events (random impacts).
-Tends to reduce genetic variation, and thus push evolution in a
certain direction

Question 24

give an example of genetic drift

Answer 24

in a field the most common flower in red.
A wildfire kills off most of the red flowers in a field, only white and pink flowers remain.
in the next generation, pink flowers are the most common.

Question 25

explain the bottleneck effect

Answer 25

▪ A sudden change in the environment (ex. fire, flood) can drastically reduce the size of a population
▪ By chance alone, certain alleles may be over-represented, under-represented, or absent among the survivors

Question 26

explain the founder effect

Answer 26

When a few individuals become isolated from a larger population, the smaller group may establish a
new population whose gene pool differs from the original population (often far reduced in size)

Question 27

explain gene flow

Answer 27

▪ Transfer of alleles into or out of a population
▪ Related to movement and connectivity
▪ Tends to increase genetic variation
▪ Can increase or decrease fitness

Question 28

explain mutations

Answer 28

▪ Change in one or several genes that can be transmitted to subsequent generations
▪ Can increase genetic variation
▪ Can increase or decrease fitness, depending on context, some are mild and boost trait variability, some are fatal

Question 29

Hardy-Weinberg equilibrium

Answer 29

The Hardy-Weinberg principle describes a hypothetical population that is not evolving

Question 30

what are the conditions for Hardy-Weinberg equilibrium (non-evolving populations)

Answer 30

1. No mutations
2. Random mating
3. No natural selection
4. Extremely large population size
5. No gene flow