Biology Lecture 2 Ecology

Question 1

define population

Answer 1

all the individuals of a given species that live and reproduce in a particular time and place

Question 2

define community (4)

Answer 2

local populations of multiple species that may interact with one another

Question 3

why is there a spatial distribution of some species

Answer 3

different feeding areas and breeding areas

Question 4

what are the two types of distribution of species (4) (4)

Answer 4

spatial and temporal

Question 5

explain the temporal distribution of species

Answer 5

different times

Question 6

niche definition

Answer 6

the ways an organism uses the resources of its environment

Question 7

explain the competitive exclusion principle

Answer 7

complete competitors occupying identical niches cannot coexist

Question 8

define the fundamental niche (4)

Answer 8

habitat that a species is capable of using, based on physiological needs

Question 9

define the realised niche (4)

Answer 9

actual conditions under which species is found, incorporates ecological factors, such as competition.

Question 10

define a keystone species (4)

Answer 10

a species that has a disproportionately large impact on the community

Question 11

trophic cascade definition (4)

Answer 11

processes at an upper trophic level flow down to two or more lower levels

Question 12

explain top-down control

Answer 12

this is very relevant, e.g., keystone species removed from both terrestrial and aquatic ecosystems

Question 13

explain bottom-up control

Answer 13

changes to primary producers affect higher trophic levels

Question 14

what are the key elements of the environment

Answer 14

temperature water sunlight soil

Question 15

what determins which organisms live in a particular climate or region (4) (4)

Answer 15

nature of the physical environment largely determines this

Question 16

temperature

Answer 16

most organisms are adapted to live within a relatively narrow range of temperatures and wil not thrive if temperatures are colder or warmer, e.g. growing seasons of plants is affected by temperature

Question 17

water

Answer 17

all organisms require water. on land, water is often scarce, so patterns of rainfall have a major influence on life

Question 18

sunlight

Answer 18

almost all ecosystems rely on energy captured by photosynthesis. the availability of light influences the amount of life an ecosystem can support, particularly below the surface in marine communities

Question 19

soil

Answer 19

the physical consistency, pH, and mineral composition of the soil often severely limit terrestrial plant growth, particularly the availability of nitrogen and phosphorus

Question 20

how can responses to environmental variation be seen in the short-term

Answer 20

organisms have variety of ways of coping with environmental change

Question 21

how can responses to environmental variation be seen in the long-term

Answer 21

natural selection can operate to make a population better adapted to its environment

Question 22

why do organisms have homeostatial abilities (4)

Answer 22

they’re a product of natural selection acting in a particular environment setting over time, which explains why an individual organism that is moved to a different environment may not survive.

Question 23

what is a norm of reaction

Answer 23

the ability to produce multiple phenotypes from a single genotype

Question 24

If such flexibility is useful, why aren’t all traits so plastic?

Answer 24

The presumed answer is that such flexibility has a cost such that individuals that are genetically programmed to produce only a single phenotype have an advantage that offsets the advantages of a large norm of reaction.

Answer 25

The existence of norms of reaction has several important consequences. Such flexibility is obviously useful to a species that may find itself in different environments, particularly sedentary species that cannot just get up and move. However, it is important to remember that such differences in phenotype among individuals do not reflect genetic differences-rather, individuals may be genetically identical, but still have grown up in different environments. Of course, a further consequence of this is that such nongenetic differences are not transmitted to the next generation because they are not genetically inherited.

Question 26

example of a behavioral adaptation

Answer 26

Many animals deal with variation in the environment by moving from one patch of habitat to another, avoiding areas that are unsuitable.

Answer 27

The ability of an individual to alter its physiology, morphology, or behavior is itself an evolutionary adaptation, the result of natural selection. The results of natural selection can also be detected by comparing populations of the same species that live in different environments.

Answer 28

Lizards that live in different climates exhibit physiological adaptations for coping with life at different temperatures. Desert lizards are unaffected by high temperatures that would kill a lizard from northern Europe, but the northern lizards are capable of running, capturing prey, and digesting food at cooler temperatures at which desert lizards would be completely immobilized.

Question 29

types of interaction

Answer 29

mutualism parasitism