ecology and the environment 4.1, 4.2, 4.5, 4.6, 4.7, 4.8, 4.9, 4.10, 4.13, 4.14, 4.15, 4.11B

Question 1

what’s an ecosystem?

Answer 1

system or area where organisms interact with their physical environment

Question 2

what’s a producer?

Answer 2

organisms which make their own food
photosynthesising plants

Question 3

what’s a consumer?

Answer 3

an organism which eats other living things
animals

Question 4

what’s a decomposer?

Answer 4

organisms which secrete digestive enzymes to decay dead organic matter to obtain food
they help to recycle nutrients

Question 5

what’s abiotic?

Answer 5

non-living factor

Question 6

whats biotic?

Answer 6

living factor

Question 7

whats habitats?

Answer 7

places where specific organisms live

Question 8

practical
measuring the living organisms in an ecosystem:

Answer 8

use quadrat
use a 50cm by 50cm square that has an area of 0.25cm^2
- calculate the total area of the habitat
- place the quadrant on the ground using random sampling
- count the number of individuals of the chosen pieces inside the square
- calculate the average number of individuals in the quadrant
- calculate how many quadrants fit into the total area
- multiply the number of quadrats by the average number of individuals

Question 9

what’s a population?

Answer 9

the total number of individuals of one species in a particular habitat at a particular time

Question 10

whats random sampling and how do you carry it out?

Answer 10

to make sure data is valid - making sure our result isn’t bias

1. lay out two tape measures at right angles to make a 10m by 10m set of axes
2. generate pairs of random numbers between 0-10 to make coordinates
3. use coordinates to place quadrat

Question 11

what is the con of quadrat sampling?

Answer 11

habitats are not uniform as there will be differences in abiotic conditions, this can affect the distribution of population

Question 12

what is a community?

Answer 12

the population of all species present in an ecosystem at a particular time

Question 13

how do species interact in a community?

Answer 13

feeding, recyling nutrients
competition for resorces
using abiotic resorces

Question 14

what does an arrow mean in a food chain?

Answer 14

eaten by
shows direction that the energy and biomass moves

Question 15

what are the stages of a food chain/web called?

Answer 15

trophic levels

Question 16

what’s the first organism in a food chain called?

Answer 16

producer

Question 17

what is the first animal in a food chain/web called?

Answer 17

primary consumer

Question 18

what is the second animal in a food chain/web called?

Answer 18

secondary consumer

Question 19

whats after the secondary consumer in a food web/chain?

Answer 19

tertiary consumer

Question 20

what is very useful about food webs?

Answer 20

they show the links between species in a community

Question 21

what are pyramids of number?

Answer 21

show the number of each organism in an ecosystem
can be odd shapes

Question 22

what are pyramids of biomass?

Answer 22

drawn to show the total mass of organisms in each trophic level
more accurate way of looking at the relative amounts of organisms

Question 23

what’s the unit for the food we eat?

Answer 23

kilojoules

Question 24

how do we express the energy available at a trophic level?

Answer 24

kilojoules per square meter per year

Question 25

does the energy fluctuate between trophic levels?

Answer 25

yes it should decrease in energy between each trophic level

Question 26

which is the least efficient transfer within food webs/chains?

Answer 26

light energy to produces some light will miss the plant some light is reflected off the cuticle some light has the wrong wavelength and not absorbed by chlorophyll

Question 27

why is only 10% of energy passed from one trophic level to another?

Answer 27

- some parts of the organism is not eaten - some parts are not digested and absorbed - they are egested as faeces - some materials are respired (for muscle contraction, body temperature etc)

Question 28

what are bacteria and fungi called in the nitrogen cycle and why?

Answer 28

called decomposers because they break down the dead remains and release chemicals for plants to use again

Question 29

what is nitrogen fixation?

Answer 29

when nitrogen gas is converted into ammonia when nitrogen fixing bacteria in the soil and roots of legume plants absorb nitrogen and reduce it to make ammonia

Question 30

what is nitrification?

Answer 30

when ammonia is converted to nitrates by nitrifying bacteria and nitites

Question 31

what can plant food only do in the nitrogen cycle?

Answer 31

plant roots can only absorb the nitrates combined with carbohydrates to form amino acids which are made into proteins, and DNA & RNA

Question 32

what's assimilation?

Answer 32

animals eat plants they digest proteins and DNA used by animals to synthesise new proteins and DNA

Question 33

what's decompostion?

Answer 33

when a plant or animal dies and its tissues are decomposed by bacteria and fungi

Question 34

what's denitrification?

Answer 34

when nitrates are converted into nitrogen gas by denitrifying bacteria

Question 35

give some examples of legume plants:

Answer 35

peas, beans, clovers

Question 36

why are leguminous plants used on farms?

Answer 36

as they make the soil much more fertile

Question 37

carbon cycle: when plants photosynthesis carbon atoms from carbon dioxide become part of glucose molecules in plant, what will happen to this carbon?

Answer 37

- respiration = some of the glucose will be broken down via respiration and will become carbon dioxide again therefore released back into the air - eaten = the animals respire, release some of it back into the air as carbon dioxide - decomposers = when animal/plant dies decomposers will feed on them and the carbon becomes part of decomposers bodies therefore when they respire they release carbon dioxide into the air again - locking in = when living things don't fully decay therefore fossil fuels are formed - combustion = when fossil fuels are burnt carbon is released into atmosphere

Question 38

what human activity acts as a source of CO2?

Answer 38

- burning fossil fuels - slash and burn forest clearance

Question 39

what human activity acts as a source of methane?

Answer 39

- generate by bacteria in anaerobic conditions

Question 40

what human activity acts as a source of methane?

Answer 40

- burning fossil fuels

Question 41

potential effects of global warming:

Answer 41

- melting of polar ice caps = sea levels rise = flooding - destruction of habitats = extinction of species - drought and desertification - increased extreme weather events - spread of disease - change in crops - increase in heat related illness and death