Populations in ecosystems

Question 1

What is ecology?

Answer 1

The study of the inter-relationships between organisms and their environment. The environment being abiotic factors and biotic factors

Question 2

What are abiotic and biotic factors?

Answer 2

Abiotic = non-living factors

Biotic factors = living factors

Question 3

What is a population?

Answer 3

A group of individuals of one species that occupy the same habitat at the same time and are potentially able to interbreed.

Question 4

What is a carrying capacity?

Answer 4

The size of population that the ecosystem can support.

Question 5

What is a community?

Answer 5

All of the populations of different species living and interacting in a particular place at the same time.

Question 6

What is a habitat?

Answer 6

The place an organism normally lives and is characterised by physical conditions and the other types of organisms present. Within each habitat there are microhabitats.

Question 7

What is an ecological niche?

Answer 7

Describes how an organism fits into the environment referring to where an organism lives and what it does there.

Question 8

What are organisms normally found?

Answer 8

In places where the local environment conditions fall within the range that their adaptation enable them to cope with.

Question 9

Why does no population grow indefinitely?

Answer 9

Limiting factors eg, availability of food, light, oxygen and shelter.

Question 10

Name 4 abiotic factors?

Answer 10

Temperature, light, pH and water/humidity

Question 11

What is intraspecific competition?

Answer 11

Individuals of the same species compete with one another for resources.

Question 12

What is interspecific competition?

Answer 12

Individuals of different species compete for resources.

Question 13

What is abundance?

Answer 13

The number of individuals of a species in a given space.

Question 14

Random sampling

Answer 14

Measure out a grid and choose random coordinates to take the sample from.

Question 15

How do you calculate the estimated population size from the mark-release recapture technique?

Answer 15

(Individuals in first sample x individuals in second sample) / number if marked individuals recaptured

Question 16

What assumptions must you make when doing the mark release recapture technique?

Answer 16

• The marked individuals distribute themselves evenly among the unmarked population.
• There is no emigration of immigration.
• There are no births or deaths.
• The mark is not toxic, make the organism vulnerable to predation or wear off.

Question 17

What is a pioneer species?

Answer 17

Colonise an inhospitable environment in the first stage of succession.

Question 18

Name 6 features of a pioneer species.

Answer 18

• Reproduce asexually,
• Dispersed by wind,
• Seeds germinate rapidly,
• Can photosynthesise,
• Fix nitrogen from the atmosphere as it is unavailable from the ground as their is no soil,
• Can tolerate extreme conditions.

Question 19

What is a climax community?

Answer 19

One which remains stable over a long period of time.

Question 20

Name 4 main reasons for conservation.

Answer 20

• personal,
• ethical,
• economic,
• cultural and aesthetic.

Question 21

Name 5 stages of succession.

Answer 21

• The non-living environment become less hostile,
• A greater number of habitats and niches,
• Increased biodiversity,
• More complex food webs,
• Increased biomass.

Question 22

What is conservation?

Answer 22

Maintenance of ecosystems and biodiversity by management of existing resources and restoring those lost.