unit 4

Question 1

producers

Answer 1

plants that photosynthesis to produce food

Question 2

consumers

Answer 2

animals that eat plants or other animals

Question 3

decomposers

Answer 3

organisms that break down dead material and help recycle nutrients

Question 4

physical environment

Answer 4

all the non-biological components of an ecosystem. e.g; soil, water

Question 5

biotic

Answer 5

living components of an ecosystem

Question 6

abiotic

Answer 6

non living (physical) components of an ecosystem

Question 7

habitats

Answer 7

place where an organism lives, e.g’ pond

Question 8

population

Answer 8

all organisms of a specific specie found in an ecosystem at a certain time, e.g; tadpoles in a pond

Question 9

community

Answer 9

population of all species found in an ecosystem at a certain time

Question 10

what does a quadrat do

Answer 10

-when you want to know how many organisms are in a particular habitat, count a smaller, representative part of population using quadrat
-sampling should be carried out randomly

Question 11

how do organisms interact in an ecosystem

Answer 11

• interact with each other and physical environment
  -feeding among organisms- recycling same nutrients
  -competing among organisms-food, shelter

Question 12

biotic factors

Answer 12

-availability of food
-predators
-parasites
-diseases

Question 13

abiotic factors

Answer 13

-light intensity/water/temp
-soil conditions
-pollution
-oxygen conc in water

Question 14

food chain

Answer 14

simplest way of showing feeding relationships in ecosystem

—-) means eaten by

Question 15

primary consumer

Answer 15

animal that eats producer- herbivore

Question 16

secondary consumer

Answer 16

animal that eats primary consumer (carnivore)

Question 17

trophic levels

Answer 17

different feeding levels in a food chain

Question 18

food web

Answer 18

diagram showing the way different food chains are linked in an ecosystem

can predict changes in number of organisms in one food chain and how they may affect those in another

Question 19

what are ecological pyramids and the two main types

Answer 19

-represent relative amount of organisms at each trophic level in a food chain
two main types;

PYRAMIDS OF NUMBERS= represent number of organisms in each trophic level
PYRAMIDS OF BIOMASS= show total mass of organisms in each trophic level

Question 20

why biomass is lost at each trophic level

Answer 20

-only about 10% is passed on

-organisms don’t eat whole part
-organisms don’t absorb all of it
-lose in waste

Question 21

key aspects involved in flow of energy through ecosystems

Answer 21

-photosynthesis
-respiration releases energy
-biological processes release energy

-if energy is used to produce new cells, it is ‘fixed molecules’ that can be passed on

Question 22

carbon cycle process

Answer 22

carbon is stored in different places
-photosynthesis-plants take in co2 from atmosphere and convert it into biological molecules, glucose.
-carbon can either be respired by plants back out, or passed to animals that eat them
-feedings/ assimilation pass carbon along food chains
-animals could respire or eaten
-when animals and plants die they either 1) decay my microorganisms 2) can be converted into fossil fuels, burned by humans, combustion

Question 22

the greenhouse gasses and their effect

Answer 22

Sulphur dioxide- combines with water to form acid rain, damages plants, acidic lakes
carbon dioxide, nitrous oxide, methan, CFCs
contribution= burning fossil fuels, livestock, deforestation
-leads to enhanced greenhouse effect-increased warming

Question 23

enhanced greenhouse effect summary

Answer 23

-G.G trap radiation is atmosphere
-many human activities release G.G into atmosphere
-more radiation=higher temp

Question 24

biological consequences of untreated sewage and fertilizers

Answer 24

TOXIC CHEMICALS= sprayed on plants to prevent damage, cannot be broken down-bioaccumulation
UNTREATED SEWAGE= lack of sewage treatment plants- pumped into water, bacteria grows, death of organisms, eutrophication
FERTILISERS= runs off into water, causes increase in algae/ water plant growth-blocks sunlight, bacteria grows, aquatic wildlife dies, reduces oxygen in water

Question 25

biomagnification

Answer 25

increase of conc of toxic chemicals the higher the organisms in the food chain

Question 26

leaching

Answer 26

process where mineral ions are washed out of soils by rain

Question 27

eutrophication

Answer 27

process where an aquatic habitat receives large amounts of minerals-naturally or as a result of pollution of sewage/fertilizers

Question 28

algal bloom

Answer 28

excess mineral ions stimulate rapid growth of algae/water plants (algal bloom) and form on the surface
-this blocks light
-uses all oxygen in water
-low o2 levels

organic fertilizers= manure