Genetics and Variation - Competition and Succession

Question 1

what are examples of abiotic factors?

Answer 1

temperature - can denature enzymes

light - source of energy for most ecosystems

pH - affects enzyme action

water + humidity - affects transpiration rates

Question 2

what are some examples of biotic factors?

Answer 2

competition

predators

parasites and disease

Question 3

what is competition?

Answer 3

striving to win or gain something by establishing superiority over others

Question 4

when does competition occur?

Answer 4

when the niche of any two species overlaps

Question 5

what are the 2 types of competition?

Answer 5

intraspecific and interspecific

Question 6

what is intraspecific competition?

Answer 6

competition between organisms of the same species

Question 7

how does variation affect intraspecific competition?

Answer 7

variation in the population means that some organisms can compete better than others

Question 8

what is interspecific competition?

Answer 8

competition between different species

Question 9

when does interspecific competition occur?

Answer 9

when individuals of different species occupy the same niche

Question 10

what will happen during interspecific competition?

Answer 10

one species will have a competitive advantage over the other, so that population will grow while the other shrinks

Question 11

what is the competitive exclusion principle?

Answer 11

where populations of 2 species initially occupy the same niche, one will normally have the competitive advantage

Question 12

what is predation?

Answer 12

the preying of one animal on others

Question 13

what are the stages of the predator-prey cycle?

Answer 13

1. predators eat prey so population of prey decreases
2. fewer prey alive to predators in greater competition with each other
3. predator population reduced as some cannot catch enough prey to survive or reproduce
4. fewer predators alive so less prey eaten so more survive and reproduce
5. population of prey increases
6. with more prey available, predator population increases

Question 14

what is succession?

Answer 14

the process by which an ecosystem changes over time

Question 15

what are the 2 types of succession?

Answer 15

primary and secondary

Question 16

when does primary succession occur?

Answer 16

on land that is inhospitible or newly formed with no organic material

Question 17

what is a pioneer species?

Answer 17

the first species to colonise an area

Question 18

what features do pioneer species usually have?

Answer 18

asexual reproduction

production of seeds/spores

photosynthesis

tolerance to extremes

Question 19

what is the climax community?

Answer 19

an ecosystem that remains stable and supports the largest and most complex community of animals and plants as it can

Question 20

what are the stages of primary succession?

Answer 20

1. pioneer species colonise area
2. they die and microorganisms decompose the dead organic material forming a basic soil
3. conditions less hostile as basic soil can retain water so more species move in
4. organisms that are better adapted outcompete previous species
5. climax community reached

Question 21

when does secondary succession occur?

Answer 21

when land has been altered in some way eg fire, disease, grazing, agriculture

Question 22

what is the main difference between primary and secondary succession?

Answer 22

there’s already a soil layer for secondary succession so it starts at a later stage than primary

Question 23

what is conservation?

Answer 23

the management of the Earth’s natural resources by humans in such a way that maximum use of them can be made in the future

Question 24

what are the reasons for conservation?

Answer 24

personal - maintains our planet

ethical - other species were here before us

economic - there is a huge gene pool with capacity to make millions of useful substances

cultural + aesthetic - enrich our nature

Question 25

why is succession managed?

Answer 25

because in the climax community, species that were present in earlier stages of succession will have often died out due to habitat disappearing or being outcompeted