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Biology S2 2024 > Populations > Flashcards

Populations Flashcards

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1
Q

population definition

A

group of individuals of the same species living in the same location with the individuals

  • same resources
  • similar environmental conditions
  • interacting with each other

with geography being at different scales

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2
Q

boundaries of populations

A

geographic areas, including natural features such as lakes, or arbitrary features like national parks or countries

matched to the purpose of studying the organism

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3
Q

size in population property

A

how many individuals are in the population and how does this change over time

births, death, immigration and emigration (leaving)

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4
Q

distribution population properties

A

clumped (helping one another)
uniform (competition between individuals of the same species, not enough resources to be close to one another)s
random (just kind of becasue lol)

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5
Q

population structure properties

A

male or female, age etc.

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6
Q

what is population ecology?

A

the scientific study of population in relation to the environment and resources

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7
Q

how to reduce population size

A

increase in deaths (introduce a disease)
decrease births (contraceptives)
reduce immigration into the population (barriers such as fences)
increase in emigration (introduce a potential predators or competitor)

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8
Q

accuracy vs precision

A

accuracy is close to the expected

precision is close together in trials

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9
Q

Imperfect detection

A

abundance = number seen/probability of detection

pr detection is 75%

individuals remain undetected and there is a risk of underestimating species you use this

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10
Q

Mark recapture

A

catch some, mark, release, catch more, calculate with imperfect detection

assumptions:
- marks dont decrease survival
- marks are durable
- probability of recapture remains constant
- closed populations

can also use natural marks

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11
Q

R species

A

small, short lived species wiht large reproductive output

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12
Q

k species

A

large, long lived, species with small reproductive output

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13
Q

demography

A

quantifying the patterns of births and deaths to help determine population size changes

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14
Q

exponential population growth

A

population grows exponentially (births greater than deaths)

population at time = initial population x e ^ per capita growth rate x time interval between 0 and t

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15
Q

logarithmic population growth model

A

when population growth is limited by resources

exponential growth x ( carrying capacity - initial population)/ carrying capacity

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16
Q

density dependent factors

A

competiton for resources
predators
disease
these factors are negative density factors
they have more impact the more dense a population is

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17
Q

density independent factors

A

severe heat waves
storm events
pollution
mostly abiotic factors
regardless of population size, these events will have large effects on the population size

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18
Q

what is environmental stochasticity

A

unpredictable fluctuations in environmental conditions that effect population sizes

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19
Q

demographic stochasticity

A

change in birth and death of individuals caused by chance

20
Q

metapopulations

A

group of geographically isolated populations linked together by dispersals, together many metapopulations make up a geographic range

21
Q

source vs sink populations

A

source
- source of individuals for a population
- support local growth and can be net exporters of indivduals to other patches

sink
- get more immigration than they produce
- mortality rates exceed births and populations are reliant on source population immigration

22
Q

colonisation rate

A

the proportion of unoccupied sites that become occupied per unit time

23
Q

extinction rate

A

the proportion of occupied sites that go extinct per unit of time

24
Q

3 types of dispersal

A

regular/uniform
random
clumped

25
Q

natal vs breeding dispersal

A

natal dispersal
from place of birth to place of first breeding

breeding dispersal
change of place of breeding

26
Q

dispersal vs migration

A

dispersal refers to the spreding of individuals from others

migration is the large-scale movement of members of a species to a different environment (periodically and generally unpredictable)

27
Q

how does dispersal effect population dynamics?

A

invasive species
dynamics of metapopulations
- contribute to local extinction
- colonisation

28
Q

what is an ecological community?

A

a community is a group of potentially interacting species that occur together in space and time

29
Q

how are ecological communities defined?

A

subset of species
proportion of species
the bioregions (plain, hill, coastal biomes etc)

30
Q

why are not all species present in a particular community?

A

dispersal
environment isnt suitable
species interactions are unfavourable or more favourable elsewhere

the species present can be viewed as the result of a set of filters where these are the sieves

31
Q

how does regional species pool effect ecological communties?

A

evolution and diversification
extinction
dynamic interactions between teh two

32
Q

dispersal effects species and ecological communities

A

species introduced by poeple are clear examples of changing dispersal
can also occur naturally

33
Q

environmental/abiotic features that affect ecological communities

A

disturbances that change resource availability or the physical environment
bushfire, flood etc.

34
Q

species interactions effect on EC

A

invasive species can have large impact on species populatiosn

35
Q

succession

A

natural changes in the composition and structure of an ecological community over time

the replacement of one community by another

36
Q

ecological succession

A

a gradual change in community structure over time due to environmental disturbance

can be primary or secondary

37
Q

primary succession

A

organisms colonise bare rock either by volcanoes or retreting glaciers

often pioneer (hardy) species like fungus, algae, lichen and cyanobacteria

38
Q

climax community

A

a community wiht a relatively stable species composition

39
Q

secondary succession

A

organisms re-colonise a habitat that was cleared by a disturbance that left the soil in place

40
Q

colonisation with succession process

A

pioneer plants, soil, shrubs, trees

41
Q

hwo do communities differ?

A

species and relative abundance
the sizes and layers of vegetation

42
Q

species richness

A

number of species

43
Q

shannon-wiener index

A

species richness with species evenness

how many species, and how evenly are they proportioned to each other?

does not measure abundance!

44
Q

what is an ecosystem?

A

community of living and non-living things that interact in an area

45
Q

biodiversity

A

measure of teh variety of biological species in an ecoststem

46
Q

How to measure species richness and evenness

A

quadrat (region) is selected and the used to represent the ecosystem diversity estimates.

Usually use more than one randomly placed, but make sure you analyse the composition of the area (meadow, forest, edge area etc), so you get an accurate representation

47
Q

Functional diversity

A

ecological communities that have greater species diversity can also have greater functional diversity

making them more productive and more stable

this can be because
- wider range of resources
- wider range of responses

Biology S2 2024 (14 decks)

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