6.6 ecosystems

Question 1

define ecosystem

Answer 1

a community of animals, plants and bacteria interrelated with the physical and chemical environment

Question 2

define habitat

Answer 2

a place where an organism lives

Question 3

define population

Answer 3

all of the organisms of one species who live in the same lace at the same time and can breed together

Question 4

community

Answer 4

al the populations of different species who live in the same place at the same time and can interact with each other

Question 5

define biotic factors

Answer 5

environmental factors associated with living organisms in an ecosystem that affect each other

Question 6

give 6 examples of biotic factors

Answer 6

producers
consumers
decomposers
predation
disease
competition

Question 7

define abiotic factors

Answer 7

non-living components of an ecosystem that affect other living organisms

Question 8

give 6 examples of abiotic factors

Answer 8

light intensity
soil pH
water availability
humidity
temperature
concentration of pollutants

Question 9

why are ecosystems referred to as dynamic

Answer 9

because ecosystems are changing

Question 10

what are the three types of changes in an ecosystem that affect population size

Answer 10

cyclic changes
directional changes
unpredictable changes

Question 11

define cyclic changes

Answer 11

changes that repeat themselves in a rhythm

Question 12

give an example of a cyclic change

Answer 12

tides
predator and prey relationship

Question 13

define directional changes

Answer 13

changes that aren’t cyclic and go in one direction. They tend to last longer than the lifetime of organisms with the ecosystem

Question 14

give an example of a directional change

Answer 14

erosional processes
depositional processes
glaciation

Question 15

define erratic changes

Answer 15

theses changes have no rhythm or constant direction

Question 16

give examples of erratic changes

Answer 16

hurricane
earthquake
tsunami

Question 17

define biomass transfer

Answer 17

transfer of biomass from one trophic level to another

Question 18

define trophic level

Answer 18

the level at which an organism feeds in a food chain

Question 19

how is biomass lost in a food chain

Answer 19

dead organisms
not all of the animal being eaten
respiration
senses
reproduction
heat energy

Question 20

what is the trend in biomass as you go up a food chain

Answer 20

biomass is less at higher levels

Question 21

what is biomass

Answer 21

dry mass of the organism

Question 22

How is biomass obtained by scientists

Answer 22

drying the organism by putting it in an oven to evaporate all of the water

Question 23

how do you calculate the ecological efficiency of the transfer of biomass

Answer 23

(biomass at higher trophic level/biomass at lower trophic level)*100

Question 24

define productivity

Answer 24

the rate of production of new biomass by producers

Question 25

define gross primary productivity

Answer 25

the rate at which plants convert light energy into chemical energy through photosynthesis

Question 26

define net primary productivity

Answer 26

the rate at which energy is stored as biomass by the producer that is available for the next consumer

Question 27

what is the difference between primary and secondary productivity

Answer 27

primary - plant secondary - animal

Question 28

how can we make energy conversion more efficient when farming plants

Answer 28

greenhouses fertiliser light banks pesticides crop-rotation

Question 29

How cans humans manipulate energy transfer when farming animals

Answer 29

battery farming antibiotics killing them young selective breeding

Question 30

how do saprotrophs eat?

Answer 30

they secrete enzymes on dead or waste material which digest the material into smaller pieces which are then absorbed into the saprotroph's body

Question 31

why are bacteria and fungi vital for recycling within ecosystems

Answer 31

if bacteria and fungi did not break down dead organisms, energy and valuable nutrients would remain trapped within the dead organism

Question 32

why do living things need nitrogen?

Answer 32

to make proteins and nucleic acids

Question 33

what kind of nitrogen do plants require

Answer 33

fixed nitrogen (NH4+,NO-)

Question 34

how is fixed nitrogen produced

Answer 34

lightning and the Haber process only makes up about 10% of fixed nitrogen the rest is by bacteria

Question 35

how much of the atmosphere is made of nitrogen

Answer 35

79%

Question 36

what bacteria fix nitrogen

Answer 36

Azotobacter Rhizobium

Question 37

Describe the role of Azotobacter

Answer 37

bacteria that lives freely within the soil and fix nitrogen gas, which is in the air within the soil, using it to manufacture amino acids

Question 38

what is the role of Rhizobium

Answer 38

lives inside the root nodules of leguminous plants and is nitrogen fixing It has a mutualistic relationship with the plant by supplying it with fixed nitrogen and receiving carbon compounds such as glucose

Question 39

what is the role of leghaemoglobin

Answer 39

absorbs oxygen to keep conditions anaerobic for nitrogen reductase

Question 40

What is ammonification

Answer 40

organic nitrogen in soil and urea ---> NH4+ by bacteria involved in putrification

Question 41

what is nitrification

Answer 41

chemoautotrophic bacteria in soil oxidise ammonium ions to nitrite ions and the into nitrate ions

Question 42

What is the role of nitrosomanas

Answer 42

oxidising ammonium ions to nitrite ions(nitrification)

Question 43

What is the role of Nitrobacter

Answer 43

Oxidise nitrite ions to nitrate ions (nitrification)

Question 44

Whet is denitrification and its conditions

Answer 44

occurs in anaerobic conditions such as waterlogged soils and use nitrates as a source of oxygen to produce nitrogen gas and nitrous oxide

Question 45

define climax community

Answer 45

the final stable community that exists after the process of succession has occurred

Question 46

define deflected community

Answer 46

happens when succession is stopped or interfered with such as by grazing or lawn mowing

Question 47

define pioneer species

Answer 47

the species that begins the process of succession

Question 48

define succession

Answer 48

progressive changes in a community of organisms over town