3.7.4.1 Populations in ecosystems

Question 1

Species

Answer 1

organisms can interbreed to produce fertile offspring

Question 2

Population

Answer 2

group of the same species in the same area

Question 3

Community

Answer 3

groups of different species within the same area

Question 4

Ecosystem

Answer 4

the community and the non living aspects

Question 5

Habitat

Answer 5

small part of ecosystem where a population lives

Question 6

Abiotic factors

Answer 6

non living parts of a habitat

Question 7

Biotic factors

Answer 7

living parts of a habitat

Question 8

Biotic factors

Answer 8

living parts of a habitat

Question 9

Niche

Answer 9

the role a species has in its community / environment

Question 10

2 species being unable to occupy the same niche means that …

Answer 10

both species are able to be successful in the same ecosystem

Question 11

Is competition biotic or abiotic?

Answer 11

biotic

Question 12

If individuals are more similar, what does this mean for the competition?

Answer 12

competition more intense

Question 13

Intraspecific competition

Answer 13

competition within the same species

Question 14

Interspecific competition

Answer 14

competition between different species

Question 15

Intraspecific competition and competition and population

Answer 15

• variation in population means some organisms are able to compete (survival of the fittest)
• availability of resources determine size of population
• relatively stable population

Question 16

Interspecific competition and competition and population

Answer 16

one population will grow and the other will shrink - individuals of different species occupying parts of same niche, one species will have competitive advantage over the other

Question 17

Open system

Answer 17

• nature
• both biotic & abiotic factors can change
• not controlled

Question 18

Closed system

Answer 18

• for microbes in lab
• start with limited resources
• controlled factors (e.g. conc of sugar, o2)

Question 19

4 stages of population growth curve (open system)

Answer 19

1. lag phase
2. log phase
3. effects of limiting factors
4. carrying capacity

Question 20

Extra stage of population growth curve (closed system)

Answer 20

death (where cell death outnumbers cell division)

Question 21

In death stage why would cell death outnumber cell division?

Answer 21

• less or no sugars (glucose - less or no respiration)

- more toxins (waste products trapped e.g. CO2 & ethanol increase acidity)

Question 22

What happens during the log phase?

Answer 22

lots of reproduction / lots of cell division in unicellular organisms

Question 23

What happens during carrying capacity phase?

Answer 23

stabilising number of individuals

Question 24

What happens if predator increases and why?

Answer 24

• decrease in prey population

- more predation

Question 25

What happens if prey increases and why?

Answer 25

• increase in predator population

- more food for predators, able to survive and reproduce