Life On Earth

Question 1

Biotic factors

Answer 1

Living factors that affect an ecosystem

Question 2

Biodiversity

Answer 2

The number and variety of organisms found within an ecosystem

Question 3

Ecosystem

Answer 3

A natural biological unit made of living and non-living parts

Question 4

Ecology

Answer 4

The study of ecosystems

Question 5

Habitat

Answer 5

The place where an organism lives

Question 6

Examples of Biotic factors

Answer 6

Predation, competition for resources, disease, food availability, grazing.

Question 7

Examples of Abiotic factors

Answer 7

pH, temperature, moisture, light intensity.

Question 8

Biomes

Answer 8

Various regions in our planets distinguished by their climate, flora and fauna.

Question 9

Flora

Answer 9

Plant life.

Question 10

Fauna

Answer 10

Animal life.

Question 11

Niche

Answer 11

The role an organism plays within a community.

Question 12

Parasite

Answer 12

An organism that feeds from its host and causes it harm.

Question 13

Predator

Answer 13

An organism that hunts and eats other organisms.

Question 14

Decomposer

Answer 14

An organism that feeds from dead organisms and releases useful substances back into the environment.

Question 15

Food chains

Answer 15

Diagrams that show the energy flow in ecosystems.

Question 16

Energy loss from a food chain

Answer 16

90% of energy is lost as heat, movement or undigested materials.
10% is passed on.

Question 17

A population

Answer 17

Total number of organisms of one species living in a habitat.

Question 18

A community

Answer 18

Made up of all the living organisms in a habitat.

Question 19

A species

Answer 19

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

Question 20

Producers

Answer 20

Organisms that produce their own food through photosynthesis.

Question 21

Comsumers

Answer 21

Animals that eat other organisms.

Question 22

Herbivore

Answer 22

Only eats plants.

Question 23

Carnivore

Answer 23

Only eats meat.

Question 24

Omnivore

Answer 24

Eats both plants and animals

Question 25

Food webs

Answer 25

Several food chains linked together.

Question 26

Pyramids

Answer 26

Food chains in a pyramidal shaped diagram.

Question 27

Pyramid of numbers.

Answer 27

Number of organisms at each stage in a food chain.

Question 28

Pyramid of biomass

Answer 28

Dry weight or mass of organisms at each stage in a food chain.

Question 29

Pyramid of energy

Answer 29

Energy at each stage in a food chain

Question 30

Most accurate pyramid

Answer 30

Pyramid of biomass

Question 31

Nitrogen cycle

Answer 31

Decomposition by bacteria > nitrification > denitrification > nitrogen fixation.

Question 32

Abiotic factors

Answer 32

Non-living factors that affect an ecosystem

Question 33

Nitrifying

Answer 33

Bacteria convert ammonium compounds to nitrites and then further bacteria converts in into nitrates.

Question 34

Denitrifying

Answer 34

Bacteria break down nitrates and release nitrogen gas into the air.

Question 35

Nitrogen fixing

Answer 35

Free living soil bacteria and bacteria that live inside small swellings called nodules on the roots of plants can absorb atmospheric nitrogen and fix into nitrates.

Question 36

Decomposers

Answer 36

Decomposers break down waste organisms, by converting proteins and nitrogenous wastes to ammonium compounds. These ammonium compounds which contain nitrogen are then converted to nitrites and then nitrates.

Question 37

Interspecific competition

Answer 37

Competition between members of DIFFERENT species requiring similar resources in an ecosystem.

Question 38

Intraspecific competition

Answer 38

Competition between members of the same species.

Question 39

Pitfall traps are used to sample soil insects, what are sources of errors and ways to minimise them

Answer 39

Error 1: animals may eat other animals Error 2: doesn't represent entire ecosystem Way 1: disguise and put ethanol into trap Way 2: set up several traps

Question 40

Quadrats are used to sample plants, what are sources of errors and ways to minimise them

Answer 40

Error 1: doesn't represent entire ecosystem Error 2: some plants may be partially inside the quadrat Way 1: repeat Way 2: establish a set of rules for counting that everyone follows

Question 41

Quadrats

Answer 41

Used to measure the abundance of plants in an ecosystem

Question 42

Pitfall traps

Answer 42

Used to sample the ground living insects in an ecosystem

Question 43

Light meters are used to measure light intensity what are sources of errors and ways to minimise them

Answer 43

Error: observer may cast a shadow on light meter Way: hold above head height

Question 44

Moisture meters are used to measure the moisture content in the soil, what are sources of errors and ways to minimise them

Answer 44

Error: moisture from previous measurements may be on probe Way: wipe probe clean before use

Question 45

Thermometers are used to take the temperature of soil, what are sources of errors and ways to minimise them

Answer 45

Error: probe not inserted deep enough into soil Way: push into the soil to half its depth

Question 46

pH meters are used to measure the pH of the soil, what are sources of errors and ways to minimise them

Answer 46

Error: reading may be contaminated from previous measurements Way: wipe clean before use

Question 47

Identification keys

Answer 47

Used to identify unfamiliar organisms.

Question 48

Mutation

Answer 48

A random change to the genetic material of an organism; they are also the only sources of new alleles

Question 49

Rare

Answer 49

Doesn't happen often

Question 50

Random

Answer 50

Aren't guided and have no specific purpose

Question 51

Spontaneous

Answer 51

Unplanned/without cause or warning

Question 52

Variation

Answer 52

Small differences between individuals in a species.