Ecology: organisation of an ecosystem

Question 1

what do food chains represent?

Answer 1

Feeding relationships within a community

Question 2

what is biomass?

Answer 2

the total mass of living material

Question 3

what does a producer do?

Answer 3

synthesis molecules and makes glucose through photosynthesis

Question 4

how can we determine the distribution of species in an ecosystem?

Answer 4

using transects and quadrats

Question 5

what is random sampling used for?

Answer 5

compare the number of different organisms in different areas

Question 6

how do we do ‘random sampling’?

Answer 6

Question 7

what is the equation to find total population size?

Answer 7

Question 8

how do we investigate a factor (e.g light intensity) on the distribution of different plant species?

Answer 8

Question 9

what is the median?

Answer 9

• the middle set of values but first order the set of numbers from lowest to highest
• if we have an even set of numbers the median is the central 2 numbers and then we find the mean of the central 2 numbers
• e.g 5,6,7,8,8,9, central= 7,8 median=7+8=16/2
  *median= 8

Question 10

what is the mode?

Answer 10

number which appears the most

Question 11

what does the carbon cycle do?

Answer 11

returns the carbon from organims to the atmosphere as carbon dioxide to be by plants in photosynthesis.

Question 12

describe the carbon cyles what happens?

Answer 12

• plants and agae take in carbon dioxide from atmosphere in photosyntheis
• plants an algae respire some co2 is released back into atmosphere
• plants and algae are eaten by animals which also respire so co2 released into atmosphere
• all plants + animals die –> these are waste products and dead remains which are broken down by decomposing microognisms and which respire to release rest of co2 to atmosphere
• but if microognism are in anarobic conditions they will turn into fossil fuels and go through combustion by humans to release co2

Question 13

why are decomposing microogismins( bacterial or fungi) important?

Answer 13

they cycle materials through an ecosystem and returns carbon dioxide to the atmosphere and release mineral ions to the soil

Question 14

describe what happnes in the water cylcle?

Answer 14

• energy from the sun causes water to evaporate + transpiration from the ocean
• water vaper condenses to from clouds
• water in clouds precipitates- which includes rain,snow,hail
• some water hits the groud and evaporates and some water passes through rocks to form aquifers
• some water forms rivers or streams whihc go back into the ocean

Question 15

what does the water cycle do?

Answer 15

provides fresh water for plants and animals on land before draining into the seas

Question 16

how is compost made?

Answer 16

by microogimsim decomposing plant material

Question 17

why is compost needed for farmers?

Answer 17

compost is used as a natural fertiliser for growing garden plants or crops as it is rich in minerals needed for plants growth

Question 18

what are the factors which effect decomposition?

Answer 18

• temeprature
• water
• availiability of oxygen

Question 19

how does tempertaure affect the rate of decay of biological material?

Answer 19

warm temperature is good as decomposing uses enzymes to break down plant material and this works faster in the heat but if too warm enzymes will denature

Question 20

how does water affect the rate of decay?

Answer 20

decomposistiion as works fatser when plants materials are moist as the chemical reactions in decay need water

Question 21

how does oxygen affect the rate of decay?

Answer 21

decomposing microoginism carry out anarobic respiration which need a good supply of oxygen but if no oxygen carry out anarobic respiration which release methan= biogas

Question 22

what is biogas?

Answer 22

the microoginims go through anarobic respiration and produce methane

anarobic decay

Question 23

what is biogas used for?

Answer 23

biogas genertaors are used to produce mthan gas for as a fuel

Question 24

how can we investigate the effect of tmnepertaure on the rate of decay on fresh milk by meausring the PH channge? name the variables

Answer 24

independant= tmperature
depednant= time taken for soloution to ceome yellow
control= volume of lipase, milk sodium carboante, cresol red

Question 25

the graph for the experiment: here

Answer 25

Question 26

which environmental changes affect the distribution of species in an ecosystem?

Answer 26

• temperature
• availaibility of water
• composition of atmospheric gases