Part 4

Question 1

what is a fundamental unit of evolution?

Answer 1

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

Question 2

population

Answer 2

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

Question 3

natural selection enables populations to adapt to:

Answer 3

the abiotic and biotic components of their environment

Question 4

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

Answer 4

the traits evolved under natural selection

Question 5

what are three key features of a population?

Answer 5

size, range, and density

Question 6

population size

Answer 6

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

Question 7

range

Answer 7

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

Question 8

the range of any species reflects the range of ….

Answer 8

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

Question 9

population density

Answer 9

the size of a population divided by its range

Question 10

when is population distribution clumped?

Answer 10

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

Question 11

when is population distribution uniform?

Answer 11

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

Question 12

how do ecologists estimate population size?

Answer 12

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

Question 13

mark-and-recapture

Answer 13

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

Question 14

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

Answer 14

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

Question 15

community

Answer 15

the set of all populations found in a given place

Question 16

biodiversity

Answer 16

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

Question 17

how is biodiversity usually measured

Answer 17

by counting the number of species present in a particular area

Question 18

keystone species

Answer 18

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

Question 19

how might keystone species be identified?

Answer 19

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

Question 20

disturbance

Answer 20

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

Question 21

species diversity tends to be highest when…

Answer 21

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

Question 22

succession

Answer 22

the replacement of species by other species over time

Question 23

climax community

Answer 23

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

Question 24

ecosystem

Answer 24

a community of organisms and the physical environment it occupies

Question 25

what do food webs trace?

Answer 25

the cycling of carbon through communities and ecosystems

Question 26

community

Answer 26

the set of all populations found in a given place

Question 27

primary producer

Answer 27

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

Question 28

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

Answer 28

primary producers

Question 29

consumer

Answer 29

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

Question 30

primary consumers

Answer 30

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

Question 31

secondary consumers

Answer 31

predators or scavengers that feed on primary consumers

Question 32

carnivores

Answer 32

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

Question 33

decomposer

Answer 33

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

Question 34

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

Answer 34

it eventually returns to the atmosphere by the respiration of decomposers

Question 35

food web

Answer 35

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

Question 36

biodiversity

Answer 36

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

Question 37

food chain

Answer 37

the linear transfer of carbon from one organism to another

Question 38

trophic level

Answer 38

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

Question 39

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

Answer 39

through the chemical reactions of bacteria and archaeons

Question 40

how is energy in an ecosystem different than carbon?

Answer 40

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

Question 41

what generally decreases from one trophic level to the next?

Answer 41

biomass and energy

Question 42

energy transfer is….

Answer 42

unidirectional

Question 43

trophic pyramid

Answer 43

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

Question 44

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

Answer 44

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

Question 45

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

Answer 45

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

Question 46

Liebig’s Law of the Minimum

Answer 46

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

Question 47

the biodiversity of a given region reflects:

Answer 47

its level of primary productivity