19. Populations in ecosystems

Question 1

define biodiversity

Answer 1

the range and variety of living organisms within a particular area

Question 2

define biomass

Answer 2

the total mass of living material, normally measured in a specific area over a given period of time

Question 3

define climax community

Answer 3

the organisms that make up the stable, final, community that exists in a balanced equilibrium

Question 4

define community

Answer 4

the organisms of all species that live in the same area

Question 5

define conservation

Answer 5

method of maintaining ecosystems and the living organisms that occupy them.
it requires planning and organisation to make best use of resources while preserving the natural landscape and wildlife

Question 6

define habitat

Answer 6

the place where an organisms usually lives

Question 7

define hostile/harsh

Answer 7

when abiotic conditions in an environment are at the extremes

Question 8

define niche

Answer 8

all the conditions and resources required for an organism to survive and reproduce (AKA its ‘role’ in the ecosystem)

Question 9

define pioneer species

Answer 9

a species that can colonise bare rock or ground

Question 10

define primary succession

Answer 10

the progressive colonisation of bare rock or other barren terrain by living organisms

Question 11

define secondary succession

Answer 11

the recolonisation of an area after an early community has been removed or destroyed.

Question 12

define succession

Answer 12

the changes in an ecosystem, over time, in the species that occupy it

Question 13

define population

Answer 13

the number of organisms of the same species that live in the same place at the same time

Question 14

define carrying capacity

Answer 14

defined as the maximum size of the population

Question 15

what eventually determines population size

Answer 15

limiting factors

Question 16

abiotic stands for?

Answer 16

non-living

Question 17

biotic stands for?

Answer 17

living

Question 18

list some examples of abiotic factors?

Answer 18

temperature
light
PH
water

Question 19

why is temperature considered an abiotic factor?

Answer 19

links to denaturing of enzymes

Question 20

why is light considered an abiotic factor?

Answer 20

source of energy for most ecosystems

Question 21

why is PH considered an abiotic factor?

Answer 21

affects enzyme action

Question 22

why is water and humidity considered an abiotic factor?

Answer 22

links to transpiration rate

Question 23

list some examples of biotic factors

Answer 23

competition
predators
parasites and disease

Question 24

what is the competitive exclusion principle?

Answer 24

where populations of two species initially occupy the same niche, one will normally have the competitive advantage

Question 25

what are some features of a pioneer species?

Answer 25

colonises an inhospitable environment

include features that suit them to colonisation

Question 26

list some features of a pioneer species that allow them to colonise an environment

Answer 26

asexual reproduction
production of seed/spores
rapid germination
photosynthesise
nitrogen-fix
tolerance to extremes

Question 27

what are some features of a climax community?

Answer 27

a stable community over a long period of time
high biodiversity
consists of animals and plants

Question 28

what happens during primary succession?

Answer 28

abiotic environment becomes less hostile
greater number and variety of habitats and niches
increased biodiversity
more complex food webs
increased biomass

Question 29

what happens during secondary succession?

Answer 29

land altered in some way

recolonisation leads to climax community being different

Question 30

In what ways can land become altered during secondary succession?

Answer 30

fire
disease
grazing
agriculture