Ecology

Question 1

define habitat

Answer 1

the environment in which an organism lives

Question 2

define population

Answer 2

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

Question 3

define community

Answer 3

the population of all the different species living in the same habitat

Question 4

define ecosystem

Answer 4

both the biotic and abiotic parts of an environment and how they interact

Question 5

define stable community

Answer 5

the populations of the different species remain fairly constant

Question 6

define what biotic factors are

Answer 6

the living parts of an environment

Question 7

define what abiotic factors are

Answer 7

the non-living parts of an environment

Question 8

list the four biotic factors of all environments

Answer 8

1. the availability of food
2. the arrival of a new predator
   - can cause the population of a prey species to fall
3. competition between species
   - if a species is outcompeted, it’s population can fall so much that it leads to extinction
4. new pathogens

Question 9

list the six abiotic factors of all environments

Answer 9

1. light intensity
   - if it’s too low, the rate of photosynthesis will fall and plants will grow more slowly
2. temperature
3. water
   - plants and animals need water to survive
4. pH and mineral content of the soil
   - many plants can’t grow on ground that is too acidic or too alkaline
5. wind intensity and direction
   - strong winds blowing inland from the sea can cause plants to lose water
6. carbon dioxide and oxygen

Question 10

list the three types of adaptations an organism can have?

Answer 10

1. Structural
   - adaptations to the body’s shape or structure
2. Functional
   - adaptations to the body functions of an organism
3. Behavioural
   - adaptations to an animals lifestyle or behaviour

Question 11

define extremophile

Answer 11

an animal that’s adapted to live in extreme conditions

Question 12

what des every food chain start with?

Answer 12

a producer

Question 13

what would a producer usually be?

Answer 13

a green plant or, if it’s a food chain in the sea, algae such as seaweed

Question 14

what is the role of a producer?

Answer 14

synthesises complex molecules (known as biomass to scientists)

producers are so important because they are the source of all the biomass in a community

Question 15

what is the equation for total population size?

Answer 15

total population size =

area sampled

x

the number of organisms of that species counted in the sample

Question 16

what is the water cycle? (6)

Answer 16

• energy from the sun causes the water to evaporate from the surface of the sea
• the water vapour now travels into the air and cools down
• when it cools, the water vapour condenses to form clouds
• the water in the clouds then falls to the ground as precipitation
• some of this precipitation evaporates back into the atmosphere; some passes through rocks and forms aquifers; a lot of it forms streams or rivers
• the water in rivers and streams eventually drains back into the sea

Question 17

how do living organisms play a part in the water cycle? (2)

Answer 17

PLANTS take up water in their roots; this moves up the plant in the xylem, and then passes out of the leaf through the stomata

ANIMALS take in water through drinking and their food, they then release water in their urine, faeces and when they exhale

Question 18

define biodiversity

Answer 18

the variety of all the species of organisms on earth

Question 19

how can we reduce the negative effects of humans on biodiversity? (5)

Answer 19

• breeding programmes for endangered species
• protects and regenerate rare habitats
• plant field margins and hedge rows next to/in between farms
• governments reducing deforestation and carbon emissions
• recycle waste materials