populations in ecosystems (3.7.4)

Question 1

define population

Answer 1

a group of individuals of the same species that occupy the same habitat at the same time

Question 2

define community

Answer 2

all living things present in an ecosystem at a given time

Question 3

define ecosystem

Answer 3

all living and non living components of a particular area

Question 4

define habitat

Answer 4

the place where an organism normally lives and which is characterised by physical conditions and the types of other organisms present

Question 5

define ecological niche

Answer 5

describes how an organism fits into its environment. describes what a species is like, where is occurs, how it behaves, interactions with others, how it responds to its environment

Question 6

define abiotic

Answer 6

an ecological factor that makes up a part of the non biological environment of an organism

Question 7

define biotic

Answer 7

an ecological factor that makes up part of the living environment of an organism

Question 8

define carrying capacity

Answer 8

population size that can be sustained over a relatively long period. determined by limiting factors such as predation and disease

Question 9

define interspecific competition

Answer 9

competition between organisms of different species

Question 10

define intraspecific competition

Answer 10

competition between organisms of the same species

Question 11

define predation

Answer 11

one organism is consumed by another

Question 12

what are the two types of migration

Answer 12

internal and external

Question 13

what are the four stages of a population growth curve

Answer 13

lag phase
log phase
stationary phase
decline phase

Question 14

what is the lag phase

Answer 14

population is slowly increasing as organisms adjust to the new environment and start to reproduce

Question 15

what is the log phase

Answer 15

high availability of nutrients and space leads to exponential growth

Question 16

what is the stationary phase

Answer 16

population reaches its maximum as it is limited by the resources available

Question 17

what is the death phase

Answer 17

where lack of nutrients and toxic waste products cause death rate > birth rate

Question 18

examples of limiting factors

Answer 18

predation
light
oxygen
disease
competition
water
humidity
toxic waste
temperature
pH
food availability
nutrients
habitats

Question 19

why is low temperature an issue

Answer 19

slows enzyme activity and reduces the metabolic rate

Question 20

what is the competition exclusion principle

Answer 20

states that 2 species cannot coexist if they occupy the same niche (if they compete for identical recourses)

Question 21

effect of predator prey relationship on population size

Answer 21

predators eat prey
reduces prey population
predators in greater competition for prey
predator population is reduced
less prey eaten
prey population increases
predator population then increases

Question 22

what are quadrats used for

Answer 22

used for non mobile/sessile organisms

Question 23

what is mark release recapture used for

Answer 23

used for mobile animals

Question 24

random sampling method

Answer 24

use transects
random number generator for coordinates
quadrat at intersections

Question 25

when would you use systematic sampling

Answer 25

to investigate changes in habitats, along lines of succession or where there are environmental gradients

Question 26

when is a line transect used

Answer 26

records species which actually touch the transect

Question 27

how is a belt transect used

Answer 27

a frame quadrat is laid down along a straight line and species recorded in the transect

Question 28

when is an interrupted belt transect used

Answer 28

records all those species present in a number of quadrats places at fixed points along a line stretched across the habitat