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Flashcards in Part 4 Deck (47)
1

what is a fundamental unit of evolution?

populations (not individuals) that evolve, it is also a fundamental unit of ecology

2

population

all the individuals of a given species that live and reproduce in a particular place; one of several interbreeding groups of organisms of the same species living in the same geographical area

3

natural selection enables populations to adapt to:

the abiotic and biotic components of their environment

4

what determines whether a population will grow or shrink under a given set of physical and biological conditions?

the traits evolved under natural selection

5

what are three key features of a population?

size, range, and density

6

population size

the number of individuals of all ages alive at a particular time in a particular place

7

range

the extent of the geographic area over which populations of a species are distributed

8

the range of any species reflects the range of ....

climates a population a tolerate and determines how many other species the population encounters

9

population density

the size of a population divided by its range

10

when is population distribution clumped?

if resources are clustered or if close proximity to other individuals enhances fitness

11

when is population distribution uniform?

when resources are limited or if it's better to be spread out, ex. in case of predators

12

how do ecologists estimate population size?

by taking repeated samples of a population and estimating the total number of individuals from the sample to determine population density

13

mark-and-recapture

a method in which individuals are captured, marked in a way that doesn't affect their function or behaviour, and then released. The percentage of marked individuals in a later exercise of capture enables ecologists to estimate population size

14

what is an assumption that needs to be made for the mark-and-recapture method?

that the population has not changed in size between the first and second samples

15

community

the set of all populations found in a given place

16

biodiversity

biological diversity; the aggregate number of species, or, more broadly, also the diversity of genetic sequences, cell types, metabolism, life history, phylogenetic groups, communities, and ecosystems

17

how is biodiversity usually measured

by counting the number of species present in a particular area

18

keystone species

pivotal populations that affect other members of the community in ways that are disproportionate to their abundance or biomass

19

how might keystone species be identified?

species that influences the transfer of a large proportion of biomass and energy from one trophic level to another or when the species can modify its physical environment

20

disturbance

a severe physical impact on a habitat that has density-independent effects on populations of interacting species

21

species diversity tends to be highest when...

disturbance is frequent or intense enough to inhibit competition, but not so strong as to limit the number of species that can tolerate the environment

22

succession

the replacement of species by other species over time

23

climax community

a mature assembly, a final stage in succession, in which there is little further change in species composition

24

ecosystem

a community of organisms and the physical environment it occupies

25

what do food webs trace?

the cycling of carbon through communities and ecosystems

26

community

the set of all populations found in a given place

27

primary producer

an organism that takes up inorganic carbon nitrogen, phosphorus, and other compounds from the environment and converts them into organic compounds that will provide food for other organisms in the local environment

28

what is the first biological reservoir of carbon once it has been taken out of the physical environment

primary producers

29

consumer

an organism that obtains the carbon it needs for growth and reproduction from the foods it eats and gains energy by respiring food molecules; heterotrophic organisms of all kinds that directly consume primary producers or consume those that do

30

primary consumers

herbivores, which consume primary (plant or algae) producers. sometimes called grazers

31

secondary consumers

predators or scavengers that feed on primary consumers

32

carnivores

a monophyletic group of animals, including cats, dogs, seals and their relatives, that consumer other animals

33

decomposer

an organism that breaks down dead tissues, feeding on the dead cells or bodies of other organisms

34

what happens to the carbon as it is passed from one carbon to another?

it eventually returns to the atmosphere by the respiration of decomposers

35

food web

a map of interactions that connect consumer and producer organisms within the carbon cycle; the movement of carbon through an ecosystem

36

biodiversity

AKA biological diversity; the aggregate number of species, or, more broadly, also the diversity of genetic sequences, cell types, metabolism, life history, phylogenetic groups, communities, and ecosystems

37

food chain

the linear transfer of carbon from one organism to another

38

trophic level

an organism's typical place in a food web as a producer or consumer

39

when sunlight is absent (ex. depths of ocean), how does primary production occur?

through the chemical reactions of bacteria and archaeons

40

how is energy in an ecosystem different than carbon?

it does not cycle, new energy must be continually harvested by primary producers

41

what generally decreases from one trophic level to the next?

biomass and energy

42

energy transfer is....

unidirectional

43

trophic pyramid

a diagram that traces the flow of energy through communities, showing the amount of energy available at each level to feed the next. The pyramid shape results because biomass and the energy it represents generally decrease from one trophic level to the next

44

why is only 10% of energy passed to the next trophic level?

because energy is used in defecation, work, and lost as heat dissipation

45

what is the shape of the biomass diagram for marine ecosystem?

it is inverted (smaller on the bottom), because plankton are tiny and reproduce very fast

46

Liebig's Law of the Minimum

the principle that primary production is limited by the nutrient that is least available relative to its use by primary producers

47

the biodiversity of a given region reflects:

its level of primary productivity