B16 Adaptation, Interdependence and Competition

Question 1

Describe how to measure the population size of a common species in a habitat through quantitative sampling

Answer 1

• Identify organism you’re investigating
• Using a random number generator, generate random coordinates
• Count number of organisms in one quadrat
• Repeat more times for accuracy
• Multiply the number of organisms spotted as a fraction of total area sampled by the total area of the
  habitat being investigated

Question 2

Describe how to use transects to investigate the effect of a factor on the distribution of a species

Answer 2

• Choose a factor to investigate (e.g. light intensity, soil pH, trampling)
• Take a transect across the habitat, and take quadrats at regular intervals and observe any changes in
  the environmental factor and the population of the species being investigated

Question 3

What is a habitat?

Answer 3

The environment in which an organism lives

Question 4

What is a population?

Answer 4

The total number of organisms in the same species, living in the same geographical area

Question 5

What is a commuinity?

Answer 5

The populations of all the different species that live in the same habitat

Question 6

What is a biotic factor?

Answer 6

A living part of an ecosystem

Question 7

What is an abiotic factor?

Answer 7

The non living parts of an ecosystem (Amount of water, minerals in the soil etc)

Question 8

What is an ecosystem?

Answer 8

The interaction of a community of living organisms (biotic), with non living (abiotic) parts of their environment

Question 9

What types of things do plants compete for?

Answer 9

Light, space, water and mineral ions in the soil

Question 10

What types of things do animals compete for?

Answer 10

Food and water, mating partners, and territory

Question 11

What is interdependence?

Answer 11

The idea that within a community, each species depends on another species for food, shelter, pollination etc, and if one of these factors is removed, it can affect the entire community

Question 12

What is a stable community

Answer 12

A community in which the species and environmental factors remain in balance so that population sizes remain fairly constant

Question 13

Describe and explain 4 biotic factors that can affect the stability of an ecosystem

Answer 13

• Availability of food - if availability of food falls, so will number of organisms in the community
• Arrival of a new predator - can cause population of a prey species to fall, or outcompete existing
  predators, if they are both competing for the same prey
• Competition between species (Interspecific competition), outcompeted species’ populations could fall
  so much, that their number are no longer sufficient to breed - extinction
• New pathogens - can wipe out populations of species

Question 14

State 7 abiotic factors that can affect the stability of an ecosystem

(with some explanation)

Answer 14

• Light intensity - lack of photosynthesis so plants grow more slowly, lack of food
• Temperature - can affect distribution of species, and cause migration, or just kill plants
• Water - self explanatory
• pH and mineral content of soil - affects plant growth e.g lack of nitrate ions
• Wind direction and intensity - can increase rate of transpiration and water loss
• Carbon dioxide and Oxygen (2) - Photosynthesis and respiration, the level of dissolved O2 in the water can fall on hot days, and can be harmful to aquatic organisms such as fish

Question 15

What is a structural adaptation?

Answer 15

An adaptation related to body shape or structure

A camel’s hump or a leopards spots

Question 16

What is a functional adaptation?

Answer 16

Adaptations to the body functions of an organism

e.g. dry faeces and concentrated urine

Question 17

What is a behavioural adaptation?

Answer 17

An adaptation to an organisms lifestyle or behaviour

Nocturnality

Question 18

What are the benefits of thick fur in cold environments?

Answer 18

Provides insulation and reduces heat loss to the air

Question 19

What are the benefits of small ears in cold environments?

Answer 19

They have a small surface area, which decreases the rate at which heat is loss through radiation (infrared)

Question 20

What is an extremophile?

just for safety in case i ever forget

Answer 20

An organism adapted to living in extreme conditions

Question 21

What is a producer, and why are red plants not producers?

Answer 21

An organism that photosynthesis. Red plants do not contain chlorophyll, and therefore cannot photosynthesise

Question 22

Why are producers important?

Answer 22

They synthesise important molecules e.g. glucose (This is biomass, and can pass up the food chain to other organisms). The producers are the source of all biomass in a community

Question 23

What is a primary consumer?

Answer 23

An organism that eats a producer

Question 24

What is a secondary consumer?

Answer 24

An organism that eats a primary consumer

Question 25

What is a tertiary consumer?

Answer 25

An organism that eats a secondary consumer

Question 26

Define predators and prey

Answer 26

• A motile organism that eats/is eaten by another motile organism

(use your brain)

Question 27

Describe a predator/prey cycle

Answer 27

• Certain factor e.g. temperature helps to increase population of prey, (more grass idk)
• More prey offspring survive as there is more food to eat
• More prey for predators to kill and eat, so over time, predator population increases
• More predators means more prey will be eaten, so prey population falls
• Less prey means less food for predators, so predator population falls
• so on and so forth

Question 28

What is the one condition that allows for normal predator/prey cycles?

Answer 28

That they are situated in a stable community - where all biotic and abiotic factors are in balance