biodiversity & distribution of organisms ( key areas 1&2)

Question 1

what is the meaning of biodiversity?

Answer 1

The range (variety/number) of species within an ecosystem.

Question 2

what is a species?

Answer 2

A group of organisms which can interbreed and produce fertile offspring.

Question 3

state the definition of a population.

Answer 3

The total number of living organisms of one type (species) living in a habitat.

Question 4

state the definition of a biotic factor

Answer 4

BIOTIC factors are living things that affect the distribution of organisms e.g., competition for resources, grazing, predation, food availability, and disease.

Question 5

state the definition of competition

Answer 5

Competition is the struggle between individuals when resources are in short supply / limited e.g. food, light, water etc. The effects of competition include the more successful species increasing in number and less successful species decreasing in number.

Question 6

state the definition of a habitat.

Answer 6

The place where an organism lives e.g. in water, in soil, trees etc.

Question 7

state the definition of a community.

Answer 7

All the organisms (e.g. plants, animals and micro-organisms) that live in a particular area.

Question 8

state the definition of an ecosystem.

Answer 8

All the organisms (the community) living in a particular habitat and the non-living components with which the organisms interact.
Sometimes written as: Community + habitat

Question 9

name the 2 different types of competition

Answer 9

interspecific
intraspecific

Question 10

what is a producer?

Answer 10

a producer makes their own food by photosynthesis

Question 11

what is a consumer?

Answer 11

a consumer is an animal which eats other organisms

Question 12

what is a predator?

Answer 12

A predator is an animal that hunts and eats other animals

Question 13

what is a prey?

Answer 13

prey is an animal that is hunted and eaten by other animals

Question 14

what is a herbivore?

Answer 14

a herbivore is an animal which eats only plants

Question 15

what is an omnivore?

Answer 15

an omnivore is an animal which eats plants and animals

Question 16

what is a carnivore?

Answer 16

a carnivore is an animal which eats only animals

Question 17

what is a decomposer?

Answer 17

A decomposer is an organism which feeds on dead organisms.

Question 18

what do the arrows in a food chain represent?

Answer 18

they represent the direction of energy flow

Question 19

which human activities can disrupt a food web?

Answer 19

hunting, fishing, using chemicals that cause pollution

Question 20

what is interspecific competition?

Answer 20

interspecific - competition which occurs amongst different species for one or a few of the resources they require

Question 21

what is intraspecific competition?

Answer 21

intraspecific - competition which occurs amongst individuals of the same species for all resources required, intraspecific competition is more intense than interspecific

Question 22

state the meaning of an ABIOTIC factor

Answer 22

ABIOTIC factors are non - living things that affect the distribution of organisms e.g. temperature, pH, light intensity and humidity

Question 23

what happens at low levels of grazing?

Answer 23

at low levels of grazing slow growing species will die as they are out competed for resources by faster growing species

Question 24

what happens at intermediate levels of grazing?

Answer 24

at intermediate levels of grazing some of the faster growing species are eaten so as a result the slower growing species are able to survive therefore increasing biodiversity

Question 25

what happens at high levels of grazing

Answer 25

at high levels of grazing damage is caused to majority of species surviving therefore decreases biodiversity as most species die

Question 26

what are the 5 ABIOTIC factors affecting an organisms distribution?

Answer 26

pH, temperature, light intensity, humidity, soil moisture

Question 27

what source of error can occur whilst using a light meter and how would you overcome it?

Answer 27

casting a shadow over the light meter, to overcome this error do not stand between the sun and the light meter

Question 28

what source of error could occur whilst using a pH meter or soil moisture meter and how can it be overcome?

Answer 28

moisture from previous reading left on the probe, to overcome this error wipe the probe dry between measurments

Question 29

name 4 sampling methods

Answer 29

quadrat ( line transect) , pitfall trap, tree beating, tullgren funnel

Question 30

how can sampling results be more reliable?

Answer 30

Replication if sampling should be taken to provide more accurate results.

Question 31

name 5 human threats to biodiversity

Answer 31

Overexploitation, pollution, invasive species, climate change, land and water use change

Question 32

what is a niche?

Answer 32

A niche is the role that an organism plays within a community. It relates to the resources it requires in its ecosystem and its interaction with other organisms in the community. It involves competition and predation and the conditions it can tolerate

Question 33

when does competition occur?

Answer 33

Competition in ecosystems occurs when resources are in short supply

Question 34

interpretation of predator prey interaction graphs

Answer 34

• at low population the predators always lacks behind the population of prey
• at higher prey populations the predators will find more prey, eat them and the prey population will decrease
• because they have eaten more the predator population can reproduce more and their numbers increase.
• lower prey populations limit how many prey can be found and eaten by predators so predator numbers will decrease

Question 35

can predation affect biodiversity?

Answer 35

predation can increase biodiversity

Question 36

what are sampling techniques used for?

Answer 36

• to find out which plants and animals live in an ecosystem
• to find out how common/ rare plants and animals are in a given ecosystem
• to investigate the reasons why plants and animals live there

Question 37

what is a source of error for a pitfall trap and quadrat( measuring biotic factors) and how can they be fixed?

Answer 37

both - the numbers and types of organism may not represent the whole ecosystem ( take several samples to make results more reliable)
pitfall trap - trapped organisms may be eaten by birds ( cover the trap with a raised stone or leaf)

Question 38

what is a paired statement key?

Answer 38

A paired statement key is made up of pairs of statements to help identify an organism

Question 39

what is an indicator species?

Answer 39

Indicator species are species that by their presence or absence indicate environmental quality/ levels of pollution. Lichens are often used as indicators of air pollution.

Question 40

describe the 3 types of lichen and what they can tolerate

Answer 40

crusty lichen can tolerate high levels of sulphur dioxide, leafy lichen can tolerate moderate levels and hairy lichen can not tolerate Sulphur dioxide at all.

Question 41

Aquatic invertebrate indicator species

Answer 41

Invertebrate species in water tend to be used as an indicator species to determine the quality of water by their presence or absence

Question 42

Aquatic invertebrate indicator species

Answer 42

Invertebrate species in water tend to be used as an indicator species to determine the quality of water by their presence or absence

Question 43

why can deforestation impact biodiversity ?

Question 44

why can deforestation impact biodiversity ?

Question 45

why can deforestation ( biotic factor) impact biodiversity ?

Answer 45

when forests are cleared many animals may lose their habitats and or food source. Many plants and animal species are lost forever.

Question 46

what is a food chain?

Answer 46

A food chain is a diagram which shows a simple feeding relationship between organisms