populations in an ecosystem

Question 1

population

Answer 1

All the individuals of one species in the same area at the same time

Question 2

habitat

Answer 2

The range of physical, biological and environmental factors in which a species can live

Question 3

community

Answer 3

all the species in a particular area at a particular time

Question 4

ecosystem

Answer 4

a community and the non-living components of an area
they can range from very small to very large in size

Question 5

Niche

Answer 5

An organism’s role within an ecosystem
their position in the food web and their habitat

Question 6

carrying capacity

Answer 6

The maximum population size an ecosystem can support

Question 7

abiotic factors

Answer 7

Non-living conditions of an ecosystem

Question 8

biotic factors

Answer 8

Impact and interactions between organisms

Question 9

interspecific competition

Answer 9

Competition between members of different species

Question 10

intraspecific competition

Answer 10

Competition between members of the same species

Question 11

when would you use random sampling

Answer 11

when there is a uniform distribution of the plant species
to avoid bias

Question 12

What must you do to ensure your samples are representative?

Answer 12

Take a large sample (at least 30)
randomly sample

Question 13

when would you use a line transect

Answer 13

When sampling a non-uniform area
e.g. a rocky shore

Question 14

Belt transect

Answer 14

one tape measure is placed through an ecosystem that is not uniform
the quadrat is placed at every position along a tape measure

Question 15

interrupted belt transect

Answer 15

one tape measure is placed through an ecosystem that is not uniform
the quadrat is placed at set intervals along the tape measure

Question 16

what are the 3 measurements you can take when counting plants in a quadrat?

Answer 16

density
percentage cover
frequency

Question 17

density measurement

Answer 17

when you count the individualspresent

Question 18

frequency measurement

Answer 18

count how many squares out of the 100 contain the species you are investigating

Question 19

what is succession?

Answer 19

the change in an ecological community over time

Question 19

percentage cover measurement

Answer 19

investigator estimates the percentage of the entire quadrat covered with the species that is being investigated
standardise by counting 1% for every small square that is at least half covered by the plant

Question 20

when would you use mark-release-recapture?

Answer 20

Estimate the population size of motile organisms

Question 21

what is secondary succession?

Answer 21

there is a disruption that causes plants to be destroyed succession starts again, but the soil is already formed

Question 22

pioneer species

Answer 22

The first species to colonise an area
e.g. lichen

Question 22

what is primary succession?

Answer 22

a succession with a pioneer species colonizing bare rock or sand
the first time the land is colonised

Question 23

climax community

Answer 23

The final stage in succession the most stable stage

Question 24

Humus

Answer 24

a thin layer of soil that forms in early primary succession

Question 25

Conservation of habitats

Answer 25

Protecting habitats as a means to protect species maintains habitats and food sources

Question 26

effects of stabilising selection

Answer 26

the middle trait has a selective advantage and continues to be the most frequent in the population range decreases as the extreme traits are lost over time

Question 26

what is the main advantage of managing succession?

Answer 26

conserves a range of habitats and a range of food sources enables a wider range of species to survive

Question 26

assumptions of mark-release-recapture

Answer 26

the marked individuals released distribute evenly after being released no migration no births or deaths

Question 27

effects of directional selection

Answer 27

one of the extreme traits has a selective advantage occurs when there is a change in the environment the modal trait changes

Question 27

effects of disruptive selection

Answer 27

alleles for the extreme traits and the middling trait allele becomes less frequent leads to speciation

Question 28

How would you randomly sample

Answer 28

place two tape measures at right angles to create a gridded area use a random number generator to get coordinates place the quadrate at the coordinates and collect the data repeat at least 30 time

Question 28

How would you sample using a line transect

Answer 28

Place a tape measure at a right angle to the road/river/shoreline place quadrat every set distance meters (e.g. 5 metres) collect the data in each quadrat repeat placing the tape measure in parallel 30 times

Question 28

describe the mark-release-recapture method of sampling

Answer 28

an initial sample of the population is captured individuals are marked and released allow them time to randomly disperse a second sample is captured the total number captured in the second sample and the number recaptured with the marking are recorded

Question 29

describe the changes you would see in a succession

Answer 29

abiotic factors become less hostile biodiversity increases becomes more stable