life on earth

Question 1

what is a species

Answer 1

a group of organisms which can interbreed and produce fertile offspring

Question 2

biodiversity

Answer 2

the range of species within an ecosystem

Question 3

population

Answer 3

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

Question 4

habitat

Answer 4

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

Question 5

community

Answer 5

all the organisms that live in a particular area

Question 6

ecosystem

Answer 6

all the organisms living in a particular habitat and the non-living components with which the organisms interact
sometimes written as: community + habitat

Question 7

niche

Answer 7

a niche is the role that an organism plays within a community

Question 8

omnivore

Answer 8

an animal which eats plants and animals

Question 9

decomposer

Answer 9

an organism which feeds on dead organisms

Question 10

carnivore

Answer 10

an animal which eats only animals

Question 11

herbivore

Answer 11

an animal which eats only plants

Question 12

producer

Answer 12

an organism that can produce its own food

Question 13

consumer

Answer 13

an animal which eats other organisms

Question 14

prey

Answer 14

an animal that is hunted and eaten by other animals

Question 15

predator

Answer 15

an animal that hunts and eats other animals

Question 16

competition

Answer 16

competition in ecosystems occurs when resources are in short supply

Question 17

intraspecific competition

Answer 17

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

Question 18

interspecific competition

Answer 18

interspecific competition occurs amongst individuals of different species for one or a few of the resources they require
less intense than intraspecific competition

Question 19

food chain

Answer 19

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

Question 20

biotic factors

Answer 20

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

Question 21

abiotic factors

Answer 21

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

Question 22

predation

Answer 22

a predator is an animal that hunts and eats other organisms therefore it can influence where particular prey live and ultimately the biodiversity of an ecosystem

Question 23

grazing

Answer 23

grazing (herbivory) by large herbivores can affect biodiversity

Question 24

food availability

Answer 24

food availability can involve the availability of edible vegetation, eaten by herbivores, or it can involve the availability of prey, eaten by predators

Question 25

quadrats

Answer 25

a quadrat is used to mark off an exact area of the ground so that the organisms can be identified and counted
quadrats should be placed randomly
multiple samples hsould be taken and then average results calculated

Question 26

indicator species

Answer 26

indicator species indicate the quality of the environment/level of pollution by their presence or absence

Question 27

biochemistry of photosynthesis

Answer 27

photosynthesis is a 2 stage process:
light reaction
carbon fixation