2. Individual Ecology -Muddiest Point

Question 1

all organisms in nature are there where they are because

Answer 1

they have moved there - even sedentary organisms at some stage of their life was motile

movement can be passive (eg- wind blow seeds) or active (mobile)

Question 2

migration

Answer 2

the mass directional movement of large numbers of species from one location to another.

migration is typically done to avoid local unfavourable condtions

different from dispersal

Question 3

migration is different from dispersal in that

Answer 3

migration tends to be directional.
dispersal is non directional movement away from the birth or breeding site while migration is the more directional

Question 4

timescales of migration

Answer 4

they can be on the timescale of hours, days, months or years

eg- crabs move by the tide
-larger timescale - seasonal migration- time of the year moving to more favourable feeding groud

Question 5

migration may have evolved to avoid

Answer 5

intraspecific competition and intersibling competition and prevent inbreeding

Question 5

negative density dependence

Answer 5

as the population density increases, there may be a decline in fitness- mortality rates increase, birth and growth rates fall

there is more intraspecific competition as density increases

Question 6

3 main categories of migration

Answer 6

1) Repeated return trip (eg- marine zooplankton)
most common

2) one return trip (eg- pacific salmon- they go to reproduce -they can survive in varying salinities (euryhaline) - they are spawned in river systems, then migrate down to the sea, then migrate back into these river system.
euryhaline means to survive in different salinties

3) one way trip (eg- monarch butterfly - there is migration in 1 generation and then that generation mates and dies and then the new generation then migrates again - one way trip - very rare

Question 7

can you migrate in time?

Answer 7

we talked about migrating space- return trips, one way trip and one return trip

migration in time - as a form of dormancy in the life of an organism. if conditions are harsh and in the future theres some sort of expectation that the conditions would be more favourable you would see some sort of dormancy. in some cases you see development being temporarily suspended

Dormancy is an inactive period of an organism’s life cycle that permits it to survive through phases of unfavorable conditions in highly variable environments

Question 8

dormancy

Answer 8

in the humming bird you see dormancy

humming birds in order to feed their high metabolic rates go into a state of thawpa every evening. they lower their metabolic rate very very low to conserve energy when resting at night

also hibernation in bears

Question 9

one of the reasons why migration and dispersal occurs is because of

Answer 9

intraspecific competition

Question 10

response to intraspecific competition

Answer 10

disperse away - leave

compete with others for areas of space - territory

Question 10

home range

Answer 10

an area that an individual or group of animals uses, but does not necessarily defend (anywhere an organism might go throughout its entire life - can have overlap in home ranges)

Question 11

territory

Answer 11

an area that an individual defends against conspecifics - varies according to its purpose /seasons and the amount and quality of resources it contains

Question 12

core area

Answer 12

the part of the home range that an animal occupies for the majority of the time
(characterized by high use density intensity or probability of occurrence)

Question 13

what are the costs to holding territories

Answer 13

if you are an organism and you have to run around defending your territory its going to cost you energy

lead to you being injured or killed if run into other competition

Question 14

why are we holding territories?

Answer 14

the benefits have to outweigh the cost

1) improved food availability
2) more attractive to mates (eg- birds)
3) provide more food for your young
4) if you are able to hold a territory on the inside of the herd rather than on the outside then you will be less exposed to predatory risk

Question 15

are there differences in terms of territory quality

Answer 15

more individuals than there are territory

Question 16

predators consume

Answer 16

a number of prey types

usually predators will concentrate on most common prey

if relative abundance of prey species changes then what happens?
the predator will switch to feeding on the other prey item that becomes more abundant (but sometimes this does not happen)