Algemmeine Tiere - 4. Populationsökologie

Question 1

Populationsökologie

Answer 1

population structure, functional charachtaristics and dynamic

Question 2

life table

Answer 2

survival and productivity ability with age

Question 3

stochasticity

Answer 3

small populations are in greater risk of extinction

Question 4

Metapopulations

Answer 4

Same species groups that still have contact (migrating individuals). population might extinct but metapopulation stays stable

Question 5

Population in narrow sense

Answer 5

homotopic - group of individuals from the species that can repreduce.

Question 6

Unitary oraganisms

Answer 6

can only develop to specific adult

Question 7

Modulary oraganisms

Answer 7

the organisem develop, according to envrionmental factors, to many units (Bryozoa)

Question 8

What can be problematic in defining population size?

Answer 8

1. not easy to define living area. size is connected to samples species. several areas shell be compared to define distribution
2. its only an evaluation, unrealistic to count.

Question 9

the distribution might not be random

Answer 9

depends on ones resolution

Question 10

Mark & recapture

Answer 10

number of marked individuals recaptured is proportional to number of marked individuals in population.

1. no births, deaths, immigration during test.
2. marking does not affect individual.

Question 11

Population index (relativ) method in avaluating population size

Answer 11

grid frequency, time intervals, count footprints, kot…

Question 12

which factors affect population size (equation)?

Answer 12

N = N(t) + births - deaths + immigration - emmigration

Question 13

Iteroparus species

Answer 13

most of the species - have 1 or more reproduction period in life

Question 14

Semelpare species

Answer 14

live short, can reproduce once (salmon)

Question 15

Costs of high reproduction

Answer 15

Limited energy. therefore: less growh (individual), less chances to survive, worse condition for following generation

Question 16

dynamic life table

Answer 16

a group along a certin period, until the death of the last member.
Cohort: same time interval of birth -> along life

Question 17

static life table

Answer 17

a group along a certin, predefined amount of time.

Question 18

Survival curves

Answer 18

survivolshio (log10 Ix) to age. draw the 3 types and give examples

Question 19

calculate survival rate (Sx - how many of the age x survived)

Answer 19

survivorship I(x)/survivorship I(x-1)

Question 20

Discrete growth

Answer 20

births - deaths (write proof)

Question 21

R - individual grouth rate

Answer 21

b per head - d per head

Question 22

𝝺 - population grouth factor

Answer 22

N(T) = 𝝺TN(0) = (1 + R)T N(0)
𝝺 = 0 : population stays on the same size
𝝺 > 1: exponential growth
0>𝝺 > 1: smaller

Question 23

Time for duobling the size of the population depends on….

Answer 23

2 x N(0) = N(0) x 𝝺^D
2 = 𝝺D
log(2) = log(𝝺^D)
log(2) = D * log(𝝺)
D = log(2) / log(𝝺)
NOT ON ITS CURRENT SIZE

Question 24

K carrying capacity

Answer 24

How many individuals a species can last for a long time in a limited resouces environment. Mostly births = deaths

Question 25

Why is a population not growing to infitiny?

Answer 25

1. intraspecific copetition
2. K
3. 𝝺 = 1+R unrealistic: R is smaller when there are less resources.

Question 26

logistic (s) population growth

Answer 26

Population is stable when N = K (size = carrting capacity)

the right form (not seen in nature as all alrady in platau)

Question 27

Allee-Effect

Answer 27

copmensation: change in birth or death will have a copmensating reaction. BUT low density population will get even lower (hard finding partners, small group disadvantages) - passanger pigeon

Question 28

stochasticity - Why do small populations have a large chance to extinct?

Answer 28

• demography - not all that can, reproduce
• genetic factors -mutation fixing, loss of vairance
• many environmental dangers

Question 29

r/k selection theory

Answer 29

grouth rate / carrying capacity. differences in: fertility, environment stbility, size, generation time, parents caring for children

Question 30

r strategy

Answer 30

growing exponentially to “conqure” a nisch fast.

frogs, bugs

Question 31

k strategy

Answer 31

live long, till k. wales, humans

Question 32

migration

Answer 32

all species

Question 33

dipersal

Answer 33

individual far from each other (e.g eggs). to avoid incest, small population -> high dispersal