Topic 9 - Ecosystems

Question 1

What is an individual

Answer 1

a single organism

Question 2

what is a population

Answer 2

all organisms of one species in a habitat

Question 3

what is a community

Answer 3

all the organisms of different species living in one habitat

Question 4

whats an ecosystem

Answer 4

a community of organisms along with the abiotic conditions

Question 5

What does interdependence mean

Answer 5

organisms depending on each other to survive like food and shelter to reproduce

Question 6

what is mutualism and give an example

Answer 6

where both organism benefit eg) bees and plants

Question 7

what is parasitism and give an example

Answer 7

dogs and flees where one organism benefits and the other is harmed

Question 8

Name some abiotic factors

Answer 8

temperature
amount of water
light intensity
level of pollution

Question 9

name some biotic factors

Answer 9

competition

predation

Question 10

How can we study the distribution of small organisms

Answer 10

using a quadrat
then take mean total no.oragnsims/ total number of quadrats
-to find population - multiply mean by total area of habitat

Question 11

How can you study the distribution of organisms along a gradient

Answer 11

using a belt transect then plotting a graph

Question 12

Name some factors which mean that energy is lost down the food chain

Answer 12

lost as heat
not all gets eaten
faeces

Question 13

How do you calculate efficiency in energy levels

Answer 13

energy transferred to next level

/ energy transferred at previous level

Question 14

How do human activities affect biodiversity

Answer 14

• fertilisers can leach into water and cause eutrophication
• fish farming
• introducing non-indigenous species

Question 15

How does fish farming reduce biodiversity

Answer 15

-food in nets produces large amounts of waste in water
- breeding ground for parasites
-predators attracted and get trapped in nets
-sometimes fish escape and cause problems for indigenous species
(sometimes fish are stored in tanks with low biodiversity as only one species is farmed and free from plants, predators and parasites)

Question 16

How does introducing a non-indigenous species reduce biodiversity

Answer 16

• compete with indigenous species for food and if they out-compete can lead to native species to die out
• can bring new diseases into habitat

Question 17

Name some ways we can conserve and maintain biodiverisity

Answer 17

• Reforestation- more variety of trees to increase biodiversity and provide food and shelter
• conservation schemes- protect habitats and species in safe areas and introducing captive breeding programmes and seed banks to distribute rare endangered plants

Question 18

Name some benefits of maintaining biodiversity

name 4

Answer 18

• creates jobs
• protects human food supply
• minimal damage to food chains
• future medicines
• ecotourism

Question 19

What is food security

Answer 19

having access to enough food that is safe and has a right balance of nutrition

Question 20

How does increasing consumption of meat and fish affect food security

Answer 20

• overfishing can cause species to die out
• feeding fish crops that could be eaten by humans
• less biomass in a food chain

Question 21

How are environmental changes caused by human activity affecting food security

Answer 21

• burning fossil fuels releases CO2 which is a greenhouse gas which leads to global warming
• climate change reduces crop yield so less food for humans

Question 22

What does food sustainability mean

Answer 22

meeting the needs of todays population without affecting the ability of furture populations to meet their needs

Question 23

How do new pests and pathogens affect food security

Answer 23

cause damage to crops and livestock

-introduce diseases that can wipe out whole populations of crops can be damaged reducing yield

Question 24

What is reverse Osmosis

Answer 24

• a method of desalination to get rid of impurities from water
• net movement of water from a lower salt concentration to a higher salt concentration over a partially permeable membrane

Question 25

What is desalination

Answer 25

removing salts from salt water to produce potable water
-thermal desalination - salt water boiled in vessel so steam rises and leaves salts and steam condenses down pipe to form water

Question 26

How does drought occur

Answer 26

when there isnt enough precipitation

Question 27

How can farmers increase the amount of nitrates in the soil

Answer 27

crop rotation

fertlisers