population and sampling etc booklet 7 p2

Question 1

what is a community

Answer 1

populations of different species

Question 2

what is an ecosystem

Answer 2

a community with abititic (nl) components

Question 3

what does random sampling ensure

Answer 3

-theres no bias when collecting results

Question 4

what is essential of the quadrants

Answer 4

-to have a large number of them so results are represensitive

Question 5

what type of sampling is transects

Answer 5

systematic sampling

Question 6

why is random sampling used

Answer 6

-count the abundance of organisms in the ecosystem

Question 7

what is the use of systematic sampling

Answer 7

• abundance of organisms over an area that changes in the communities of plants and animals .
  -the change in species

Question 8

what sampling would you use to measure organisms over long distances

Answer 8

belt transect

Question 9

what does belt transect measure

Answer 9

change in habitats and communities through an area \
-to measure succesion
-aproximate measure of organisms present over Long distances.

Question 10

how can abundance of an organism be measured

Answer 10

by its frequency or percentage cover.

Question 11

why is the release re capture method used

Answer 11

• estimate the population of mobile animals where quadrants are impractical

Question 12

describe stage one of the release recapture method

Answer 12

-capture a REPRESENTATIVE sample of organisms and record number captured
-mark these organisms in a way that doesn’t affect their survival , doesn’t make visible to predators

Question 13

describe stage 2 of the release recapture method

Answer 13

-release these organisms for a suitable time to enable to MIX RANDOMLY within the population

Question 14

Describe the last stage of the rr method

Answer 14

-second sample of organisms should be captured and the number of marked individuals should be counted

Question 15

how to calculate the population size

Answer 15

-number captured and marked 1st sample x number captured in second sample
/ number of individuals captured in second sample that are marked

Question 16

what assumptions does the release recapture method assume

Answer 16

• organisms mix randomly
  -sufficient time must erase between recapture to allow mix
  -rganisms disperse evenly
  -marking doesn’t hinder movement or survival of organisms

Question 17

why might the size of the population in an ecosystem vary

Answer 17

• inter/intra specific comp]
  -effect of abiotic factors
  -predation
  -interactions between organisma

Question 18

what factors affect the size of populations

Answer 18

light
temp
ph

Question 19

How does light affect the population size

Answer 19

• affects photosynthesis and therefore plants growth
  -diversity of species
  -number and type of consumers in an ecosystem

Question 20

How does ph affects the population size

Answer 20

• affects the activity of enzymes
  -acidic and alkaline soils favour growth of specific plant species

Question 21

How does temperature affect the size of population

Answer 21

• enzymes meaning too warm, it denatures
  -metabolic processes like respiration and photosynthesis which controls diversity of species
  -in aquatic habitats an inc of temperature reduces the amount of dissolve oxygen available to living organisms

Question 22

what is the name of the relationships that some organisms form that they benefit from

Answer 22

mutualistic relationships

Question 23

what does a greater diversity of species mean

Answer 23

-makes an ecosystem more stable
-if one species dies , it won’t affect as there’s loads of resources available.

Question 24

what is interspecific competition

Answer 24

different spices

Question 25

infraspecific

Answer 25

same species

Question 26

why is a predator prey relationship important

Answer 26

• they control population size
  -as prey increases, the number of predators increases

Question 27

what can insecticide do to a habitat

Answer 27

-decreases prey
-predator feeds on other prey

Question 28

what is primary succession

Answer 28

the gradual change in plant and animal communities from colonisation by pioneer species to the climax community

Question 29

describe the steps in primary succession

Answer 29

1) pioneer species are first to colonise area and they change the environment

2) these changes to the habitat make it more suitable for new species with different adaptations to colonise the habitat

3) the previous species die out as they’re not adapted -new ones are better competitors and old ones become reduced in abundance

Question 30

What do the changes in the abiotic environment mean

Answer 30

make. the environment less hostile and changes species diversity increases diversety

Question 31

what does succession form

Answer 31

• a climax community where the stability of the ecosystem increases as there’s more food webs available .

Question 32

what can pioneer species do firstly

Answer 32

-tolerate the hostile environment

Question 33

what do the new species do to the old ones

Answer 33

out compete them leaving the old ones reduced in abundance

Question 34

how is succession managed

Answer 34

• grazing
  -ploughing

Question 35

what’s an ecosystem

Answer 35

community of living organism with biotic and abiotic factors of the habitat .

Question 36

what do producers do

Answer 36

photosynthesis and respiration provide evidence for evolution

Question 37

what do consumers do

Answer 37

break down large compounds into smaller ones to provide energy for growth

Question 38

what are saprobionts

Answer 38

• bacteria and fungi etc
  -break down dead organisms and are essential for the recycling of nutrients in the environment