2.3 Flashcards
What is a cohort
A group of the same species
What does the survivorship curve show
The difference between generations, populations, or different species, also shows the survivorship in a cohort
What is a log scale
A log scale is used to compare types 1-3
Why do we graph survivorship curves on a log scale
They allow a better focus on the per capita effect rather than the actual number of individuals dying
How do the survivorship curve types correlate to r- and K-selected species
r-selected species have a low survivorship because r-selected animals are just focused on having as many offspring as possible. K-selected species have a high survivorship because the parents focus on the care and preparation of the real world for the offspring
What is an example of survivorship curves that can be affected by both biotic and abiotic factors
Biotic - competition
Abiotic - temperature
What does the variable r stand for
reproduction
Why do we use the term r-selected
because r-selected animals focus on just reproducing as much as possible
What does the variable K stand for
Carrying capacity
Why do we use the term K-selected
Because K-selected animals focus on the care of the offspring
What is the trade-off between r- and K-selected
The trade-off depends on the number of expendable offspring (r-selected) for the K-selected creatures
What is an example of a species in the middle of r- and K-selected
Chickens, because the mom produces a lot of eggs but still has to care for them until they hatch
What is an example of K- vs. r-selected animals in plants
The dandelions seeds are carried by the wind, so the plant doesn’t really care about it’s offspring at all
What is the definition of type 1
Observed in populations with low mortality in young age classes but very high mortality as an individual ages
What is the definition of type 2
Type II curves represent populations where the mortality rate is constant, regardless of age
