Conservation ecology

Question 1

Give the 6 causes of genetic variation

Answer 1

Selection, mutation, gene flow, meiotic drive, non-random mating, random genetic drift

Question 2

Which types of selection increase and decrease genetic variation?

Answer 2

directional and stabilising selection increase, and disruptive selection decreases

Question 3

What is meiotic drive and how does it effect genetic diversity?

Answer 3

When one copy of a gene is passed onto the offspring more that the expected 50% f the time, decreasing genetic diversity.

Question 4

What is gene flow and how does it effect genetic diversity?

Answer 4

the transfer of genetic information from one population to another, increasing genetic diversity

Question 5

What is random genetic drift and how does it effect genetic diversity?

Answer 5

Random fluctuations of genotypes in a small population, either resulting in the loss or survival of alleles, decreasing genetic diversity.

Question 6

Give the 4 mechanisms to maintain genetic diversity

Answer 6

1. Populations are not in evolutionary equilibrium with respect to directional and/or stabilising selection
2. Deleterious mutations and selection balanced (equal disadvantageous and selected mutations)
3. disruptive selection common - frequency dependent selection, fluctuating environment, heterozygote or homozygote advantage, AKA overdominance or underdominance, respectively.
4. Flow of genes from another population

Question 7

How does inbreeding effect a population?

Answer 7

reduction in survival or viability of offspring produced, increase in homozygosity

Question 8

Give an example of a genetic bottleneck

Answer 8

wolves in Yellowstone Natural Park

Question 9

What is the population viability analysis (PVA)?

Answer 9

an estimation of probability of persistence (or extinction) over a specified time period

Question 10

What can a population viability analysis (PVA) be based on?

Answer 10

exponential, density-dependent, interactive predator-prey, metapopulation or age/state-dependent models

Question 11

What is environmental stochasticity?

Answer 11

a year-to-year variation in environment in environmental conditions (e.g. weather)

Question 12

What is the quasi-extinction threshold?

Answer 12

an arbitrary critical population value.

Question 13

Describe changes to the population of colobus monkeys in Gombe

Answer 13

hunting by chimpanzee balanced by immigration of females from other areas. Deforestation in Gombe causes fragmentation.

Question 14

How can the importance of immigration be investigated?

Answer 14

by looking at the distribution of arthropods on moss with 4 treatments: control, corriders, pseudocorridors and fragments. This provides evidence of the detrimental effects of fragmentation due to habitat destruction and the benefit of wildlife corridors.

Question 15

Give 2 reasons why metapopulations are less likely to go extinct than individual local populations

Answer 15

larger patches allow for more space for individuals and more diversity, and a higher patch density present from immigration from nearby populations.

Question 16

Give an example of a metapopulation

Answer 16

Melitaea cinxia butterfly in Finland

Question 17

Describe the Allee effect

Answer 17

population density effect due to small population size - “the social dysfunction and failure to mate successfully that occurs in some species when their population density falls below a certain threshold.”

Question 18

Give an example of the Allee effect in a population

Answer 18

In Melitaea cinxia butterflies, individuals in low density populations are more likely to emigrate.

Question 19

Give the 4 components of the human-mediated ‘evil quartet’

Answer 19

1. Habitat degradation and destruction, habitat fragmentation, overexploitation, introduction of non-native species.

Question 20

Give 3 theories as to why non-native species are successful

Answer 20

1. the enemy release hypothesis
2. the evolution of increased competitive ability (EICA) hypotesis - less predation means more energy can be put into growth/development as opposed to defense
3. resource hypothesis - more ideal combination of resources in new habitat