genetics populations evolution and ecosystems 3.7

Question 1

what is a population?

Answer 1

group of organisms of same species living in the same area at the same time that can interbreed to make fertile offspring

Question 2

what is a habitat?

Answer 2

part of an ecosystem where specific organism lives

Question 3

what is a community?

Answer 3

all populations of different species that are in the same area at the same time

Question 4

what is an ecosystem?

Answer 4

community and non living components of an environment

Question 5

what is a niche?

Answer 5

an organisms role in the environment and its position of food webs and habitat

Question 6

what is the carrying capacity?

Answer 6

maximum population size an ecosystem can support

Question 7

what are abiotic factors?

Answer 7

non living conditions of an ecosystem

Question 8

what are biotic factors?

Answer 8

living parts of an ecosystem and their interactions with each other

Question 9

examples of abiotic factors?

Answer 9

temperature pH light intensity soil conditions

Question 10

what effects does abiotic factors have on population size?

Answer 10

the less harsh the abiotic factors the more species adapted to them so larger population size

Question 11

what is interspecific competition?

Answer 11

organisms of different species compete for the same resources

Question 12

what is intraspecific competition?

Answer 12

organisms of same species compete for the same resources or a mate

Question 13

predator and prey relationships

Answer 13

• the population of both fluctuate over time
• size of populations always goes prey then predator

Question 14

what is the method for mark release recapture?

Answer 14

• inital sample captured
• organisms marked and released back into environment. number recorded
• marked organisms left for a period of time
• second sample captured
• total number of second sample recorded + number of organisms recaptured (marked)
• size of population then estimated

Question 15

how to make population size results more reliable?

Answer 15

repeat mark release recapture multiple times

Question 16

what is the formula for population?

Answer 16

(no. initial sample x no. second sample) / no. of marked organisms recaptured

Question 17

what to consider when marking organisms to make sure no harm is caused?

Answer 17

• non toxic
• must not increase chance of predation
• must not reduce chance of reproduction

Question 18

what are the assumptions for mark release recapture?

Answer 18

• population size constant
• animals always redistribute evenly
• so estimate not always accurate

Question 19

how to make sure sample is representative?

Answer 19

• large sample size
• random sampling to avoid bias

Question 20

what sampling tehcnique to use for motile organisms?

Answer 20

mark release recapture

Question 21

what sampling technique to use for non motile or slow moving organisms?

Answer 21

quadrats

Question 22

what is the method for random sampling?

Answer 22

• place two tape measures at a right angle to create a gridded area
• use random number generator to generate two coordinates
• place quadrat and collect data (percentage cover/density/frequency)
• repeat x30 and calculate mean

Question 23

where would line transects be used?

Answer 23

across a path sandy shores etc

Question 24

what are the two types of line transects?

Answer 24

belt and interrupted transects

Question 25

what is the method for line transect?

Answer 25

• place the tape measure at a right angle to the shore line
• place quadrat at every position or 5m
• collect the data (frequency percentage cover density)
• repeat by placing another 30 transects at a right angle

Question 26

pros and cons of local frequency as a measure of abundance?

Answer 26

• quick method for large sample area
• poor accuracy

Question 27

pros and cons of density as a measure of abundance?

Answer 27

• more accurate
• can be used to find species richness
• more time consuming

Question 28

pros and cons of percentage frequency as a measure of abundance?

Answer 28

• quicker than density
• useful if difficult to count organism
• subjective

Question 29

what is primary succession?

Answer 29

succession on area of land that has never been colonised before

Question 30

what is secondary succession?

Answer 30

succession on area of land that has already been colonised by pioneer species

Question 31

what are pioneer species?

Answer 31

first species to colonise bare rock or ground as they tolerate extreme conditions

Question 32

what are the stages of succession?

Answer 32

• pioneer species colonise an area
• pioneer species change the environmental conditions (abiotic factors)
• environment becomes less hostile for new species so they can survive
• become less suitable for previous species
• increase in biodiversity
• biomass increases and climax community reached

Question 33

what is conservation?

Answer 33

management of the earths natural resources by humans

Question 34

reasons for conservation?

Answer 34

• ethical
• economic
• aesthetic

Question 35

how is habitats conserved through managing succession?

Answer 35

• conservation involves preventing succession to preserve a greater number of habitats in early stages of succession so like protected areas seed banks manage wild fires etc