extinction + extirpation

Question 1

extinction

Answer 1

death of the last individual of the species

Question 2

how to demonstrate extinction

Answer 2

no individuals found where previously there had been individuals - successive searches

Question 3

extinct in the wild

Answer 3

in captivity, don’t breed well, prone to disease, low genetic diversity

Question 4

Functionally extinct

Answer 4

population greatly reduced compared to ancestral population

have decreased below MVP
obvious factors in the environment preventing populations from recovering
no longer performing their role in ecosystem

example: american chestnut, 99.97% loss due to fungal disease in 1900s

Question 5

Minimum Viable Population

Answer 5

genetic diversity may be too low for healthy breeding
greater likelihood that “chance event” could wipe out your entire population

Question 6

Why do species go extinct?

Answer 6

global extinction arises in local extirpations (extinctions in certain areas)

Question 7

Extirpation

Answer 7

local extinction of a population from a geographical range

other populations of the species survive elsewhere
N = 0

Question 8

Population + population dynamics

Answer 8

a group of individuals of the same species inhabiting the same area

changes in population size (N) and composition over time

Question 9

Density-dependent factors

Answer 9

an environment only has enough resources (food, space) to support a specific number of individuals in a population.

Question 10

Carrying capacity

Answer 10

K
The number of individuals an environment can support before resources run out or the environment begins to degrade

Question 11

Factors affecting population numbers

Answer 11

density dependence
variability in resource and birth and deaths
human impacts
extreme events
pollution
land-use change
Immigration

Question 12

Stochasticity

Answer 12

the state of the system cannot be precisely predicted given its current state, even with a full knowledge of all the factors affecting that process (random chance)

Question 13

Population processes: Allee effects

Answer 13

mate limitations (hard to find, unwanted)
loss of genetic diversity, possible bottleneck, can never get those genes back

growth rate less than expected, possible extinction

Question 14

metapopulations

Answer 14

networks of
spatially isolated populations,
connected by some exchange of individuals (or pollen, gametes) over
time.

Question 15

Gene flow

Answer 15

movement of alleles between two geographically separated populations
a single individual moving between populations can cause gene flow

Question 16

Population viability analysis use:

Answer 16

demographic fluctuations due to random variations
environmental fluctuations due to variation in predation, disease, etc
loss of genetic variability

Question 17

How have humans possibly caused extinctions

Answer 17

direct predation
secondary effects: land burning, habitat change, introduced species, cascade effects

Question 18

Continents vs Islands

Answer 18

human arrival on islands coincides with many bird extinctions
on continents, overkill of large mammals but evidence is less clear

Question 19

see biodiversity loss: recent evidence