Flashcards in Maintaining populations in the wild Deck (56)
How many populations of the grizzly bear are now in the US?
Six populations in four states due to the Western colonisation
What is the number of grizzly bears currently and past?
From 100,000 to 1,000
What is the effective population size of the grizzly bear and why?
25% because not all individuals can breed
How does this number of effective population affect the grizzly bear?
It can cause a loss in genetic variation
What is inbreeding depression?
The reduced fitness in a given population as a result of the breeding of related individuals
Why is inbreeding depression not a problem in large populations?
In large populations, individuals do not mate with close relatives
What is the result of inbreeding depression?
Weak or sterile offspring and expression of harmful genes
Where is inbreeding more likely?
In smaller populations
Why is inbreeding a cause for concern for rare species?
Threatens their survival
What is outbreeding depression?
Outbreeding depression is a scientific term that refers to when two distant relatives of the same species produce offspring less fit than themselves
What is the potential outcome from a loss of evolutionary flexibility?
How can variability in climate effect population sizes?
A wet year could increase plant growth and therefore increase herbivores which in turn could increase carnivores
How can natural catastrophes affect population sizes?
It can eliminate populations
Variability in climate is more likely to affect what population sizes?
Small population sizes, they are more vulnerable
Explain the Vortex Effect
Natural disaster may lower population size. This may lead to inbreeding depression. Meaning more vulnerable to extinction.
Give an example of a species that become victim to the Vortex Effect
Greater Prairie Chicken
Give the population in 1933, and the population in 1989
25,000 in 1933 to 50 in 1989.
What was the reason for the Greater Prairie Chickens decline?
Conversion of prairie to farmland
As a result of translocation of male Greater Prairie Chickens to larger populations what happened?
Increased egg hatching success, and increase in genetic diversity
Rarity is a natural phenomenon based on what three parameters?
In terms of the IUCN Red List what does extinct in the wild mean?
Extinct in the wild!
In terms of the IUCN Red List what does critically endangered/ endangered mean?
In danger of extinction if causal factors of decline continue
In terms of the IUCN Red List what does vulnerable mean?
Species that are likely to become endangered if casual factors of decline continue
In terms of the IUCN Red List what does near threatened mean?
Populations that are not endangered of vulnerable, but are at risk
In terms of the IUCN Red List what does least concern mean?