Lecture 17: Extinction and Extirpation Flashcards
What is extinction?
Death of the last individual of the species.
How do we classify extinction?
No individuals found where previously there had been individuals = classified as extinct.
What is extinction in the wild?
Death of last individual of the species in the wild –> Individuals persist in captivity.
What is extirpation?
Local extinction of a population from a geographical range –> Other populations of the species survive elsewhere.
What are some elements to include in a population model?
Population numbers at previous times
Intrinsic rate of population increase
Stochasticity (chance)
Population fluctuations
Carrying capacity
What are some factors that affect population numbers?
Humans (hunting/fishing)
Extreme events
Pollution
Land-use change
What is the allee affect?
When population size or density positively correlates with the average individual fitness of a population or species, particularly at low population sizes
How have humans caused extinctions?
land burning
habitat change
introduced species
cascade effects
