Eco lecture 2 Flashcards
live in pacific ocean
social animals, lie in groups
feed by themselves, sleep/rest in groups
sea otters
what do sea otters feed on?
feed on invertebrates and some feed on fish
____ fur trade shut down
last otter seen in ____ on BC coast
1912; 1929
_____ island still had remnant population fo sea otters
Amchitka
what happened to the sea otters on amchitka island?
many otters died but bc plans were already in place to move for nuclear testing, some otters were translocated to other places on coast of BC
one of those places: vancouver island (89 otters introduced here)
what happened to the relocated sea otters
a bunch died bc they couldn’t adapt quickly enough to environment
but some lived and thrived be there was lots of food and little competition
r of 0.19 is very fast for a mammal
really couldn’t grow any faster than this
why did the growth of sea otters eventually slow
why?
resources became in short supply (food, space)
sea otters compete for food so with more sea otters, more inta-competition
if r hadn’t slowed, 2008 population
vs actual 2008 population
4000 vs 1500
what does K stand for?
carrying capacity
when food gets scarce do mother sea otters produce less babies?
no
when food gets scarce why does th sea otter population go down if mothers don’t produce less children?
the children don’t survive
true or false: birth rate is not density-dependent
why?
true, for sea otters, birth rate is density-independent
as birth rate is not effected by amount of food avalible because of population numbers
is the pups death rate density-dependent?
yes
where is the equilibrium located for regulated populations?
by the density-dependent rate
how many density dependent rates does a regulated population need to have?
at least one
when is equilibrium for the number of a population?
when birth rate equals death rate
a regulated population always wants to _____
return to equilibrium
what is rN showing
exponential growth w no limit
life history strategy?
way to maximize fitness
what is an r-stretegy?
maximizing # offspring
smaller offspring
lttle to no parental care
what is k-strategy?
maximize survival of offspring
larger offspring
parental care
type 1 survivorship curve uses what life history strategy? type 2? type 3?
type 1 - k
type 2- mix
type 3 - r
total number of children of a female over her lifetime
total fertility rate
total number of children of a female over her lifetime
replacement TFR
births replace deaths meaning zero population growth
