Lecture 9

Question 1

What is Ecology and Evolution?

Answer 1

• Ecology is the study of the abundance and distribution of organisms, how organisms interact with their environment and how the environmental factors shape the abundance
  and distributions
• Evolution is the process of change within a species over time, how new species arise, and the changes of genetics in a population

Question 2

Organisms interact with their environment based on …

Answer 2

the context of the ecosystem

Question 3

Define Environment:

Answer 3

physical condition (includes conditions and organisms)

Question 4

Define Ecosystem:

Answer 4

Biotic community and the abiotic environment (living and nonliving) functioning as a system - energy/nutrient flow

Question 5

Define Population:

Answer 5

Group of individuals of the same species that occupy a given area (can compete or benefit on another)

Question 6

Define Community:

Answer 6

all populations living and interacting in an ecosystem

Question 7

Define Landscape:

Answer 7

area composed of communities and ecosystems

Question 8

Define Biome:

Answer 8

Broad scale regions dominated by similar ecosystems (Tropical Rainforest)

Question 9

Define Biosphere:

Answer 9

thin layer of earth that can support life (highest level of organization)

Question 10

Define Evolution:

Answer 10

• change through time
• the meaning of biological evolution has changed significantly over time

Question 11

Evolution does not refer to:

Answer 11

developmental change of an individual

Question 12

A population is in HWE when:

Answer 12

1) No genetic drift (i.e. infinitely large population)
2) Random mating

Question 13

Define Extinction Vortex:

Answer 13

small populations become increasingly vulnerable toward extinction

Question 14

Define Genetic Drift:

Answer 14

Is the random change of allele frequencies over generations due to chance or “sampling error”.

Question 15

True or False: Genetic drift results in losses of genetic variation

Answer 15

True

Question 16

True or False: Effects of genetic drift will be strongest in small populations

Answer 16

True

Question 17

Type of Genetic Drift: Bottleneck

Answer 17

Caused by catastrophic event that greatly reduced population size

Question 18

Type of Genetic Drift: Founder Effect

Answer 18

Caused by ecological separation through migration from original population

Question 19

Describe Bottleneck Effect:

Answer 19

• Random changes in allele frequencies in a population due to dramatic reduction of population size
  Example: Australia bushfires (2019-2020)

(Allele frequencies will differ between pre and post bottle neck populations)

Question 20

Example of Bottleneck:

Answer 20

Whooping Crane (Grus Americana): Hunted nearly to extinction, only 17 birds survived in 1938 and today the have recovered 300 birds.

Question 21

Describe Founder Effect:

Answer 21

• a small group breaks off from a larger population and forms a new population. (e.g. mainland to island)

Question 22

Example of Founder Effect in human population:

Answer 22

• Natives of Pingelap Atoll, 20 survivors of typhoon in 1775.
• Resulted in inbreeding to restore population of native island
• High frequency of recessive CNGB3 gene which causes Achromatopsia (poor vision, color blindness and sensitivity to light)

Question 23

Define/Describe Micro-satellites:

Answer 23

• Commonly used to examine nuclear DNA variation.
• Short sequence (1-6 bps) repeats.
• Micro-satellites mutate by increasing/decreasing the copies of repeats.
• One peak = one allele = homozygous.
• Two peaks = two alleles = heterozygous.
• Presumably neutral marker.

Question 24

Abbreviation of Effective Population

Answer 24

Ne

Question 25

Define "Harem" Mating System:

Answer 25

a defended group of females associated with one male

Question 26

Example of "Harem" mating system

Answer 26

Northern Elephant Seal: harem of 40-50 females, which are much smaller than the males. Males battle each other for mating dominance.

Question 27

Define Lek Mating System:

Answer 27

employed by some polygynous species and is characterized by aggregations of males that females visit primarily for breeding purposes. This results in strong sexual selection pressures on the lek, as males compete for females and females 'choose' between males.

Question 28

Example of Lek Mating System:

Answer 28

Large numbers (up to 70 or more) will gather in spring on traditional dancing grounds and strut with their chests puffed out and spiky tails spread, hoping to attract females.

Question 29

Example of Lek Mating System:

Answer 29

Large numbers (up to 70 or more) will gather in spring on traditional dancing grounds and strut with their chests puffed out and spiky tails spread, hoping to attract females.

Question 30

Equation for Calculating Effective Population Size, Ne

Answer 30

Ne- 4(Nm)(Nf) / (Nm) + (Nf) Nm = # of breeding males Nf = # of breeding females

Question 31

We have a population of 400 individuals (Census Population Size). But 200 individuals are young, non-breeders.

Answer 31

𝑁𝑒 = 4(𝑁𝑚)(𝑁𝑓) / (𝑁𝑚) + (𝑁𝑓) 𝑁𝑒 = 4 * 100 * 100 / 100 + 100 𝑁𝑒 = 40,000 / 200 𝑁𝑒 = 200