Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology updated > nutrient cycles topic 5 > Flashcards

nutrient cycles topic 5 Flashcards

(66 cards)

Start Studying
1
Q

what does an ecosystem include?

A

all the organisms living in an area, and all the abiotic conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a producer?

A

organism that makes its own food, eg a plant in photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a consumer?

A

organism that consumes on another organism to obtain its energy, rather than directly using the energy of sunlight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a primary consumer?

A

organism that directly eats a producer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a secondary consumer?

A

organism that eats a primary consumer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is a tertiary consumer?

A

organism that eats a secondary consumer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a saprobiont?

A

decomposer that breaks down complex material in dead organisms into simple matter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is biomass?

A

the mass of living material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does a food chain do?

A

describes a feeding relationship where producers are eaten by consumers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a stage in a food chain called?

A

a trophic level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does an arrow on a food chain represent?

A

the direction of energy flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what does a food web represent?

A

how many food chains in a habitat often link together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how can you estimate the chemical energy stored in biomass?

A

by burning biomass in a calorimeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what can biomass be measured in terms of?

A

the mass of carbon an organism contains, or the dry mass of its tissue per unit area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is dry mass?

A

the mass of an organism with all of the water removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how can you find the dry mass of an organism?

A

sample of an organism is dried in a low temperature oven, weighed at regular intervals, when the mass becomes constant all water has been removed, scale up to the total population/area being investigated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how much carbon is present in dry mass?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does a calorimeter find the chemical energy given off?

A

sample of dry biomass burnt
energy released used to heat a known volume of water
change in temperature of water used to calculate the chemical energy of the dry biomass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is gross primary production?

A

the total amount of chemical energy converted from light energy by plants, in a given area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how much of the GPP is lost to the environment as heat when plants respire?

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is respiratory loss?

A

GPP lost to environment when plants respire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the net primary production equation?

A

the gross primary production-respiratory loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is NPP?

A

the energy available to the plant for growth and reproduction/ energy stored in a plant’s biomass, as well as the energy available to organisms at the next stage of the food chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is primary productivity?

A

the total amount of biomass in a given area in a given time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
where do consumers store chemical energy?
in their biomass
26
how do consumers get energy?
by ingesting plant material, or animals that have eaten plant material
27
around how much energy is lost between trophic levels?
90%
28
why is energy lost between trophic levels?
not all of the organism is consumed, some parts of an organism are lost in faeces if they cannot be digested, some energy lost in excretory materials eg)urine, heat loss during respiration
29
what is the formula for net production of consumers?
net production = chemical energy in ingested food - (chemical energy lost in faeces and urine+energy lost through respiration)
30
what can the net production of consumers also be called?
secondary production, or secondary productivity when expressed as a rate
31
why do most food chains only have 4/5 levels?
insufficient energy available to support a large enough breeding population at a higher trophic level than this
32
is the mass or organisms higher or lower at higher trophic levels?
lower
33
how does energy available change the higher up the food chain you go?
energy available decreases
34
what is the equation for percentage efficiency?
(energy available after the transfer/energy available before the transfer) x 100
35
what are two methods farmers use to increase the efficiency of energy transfer?
reduce the energy lost to other organisms, reduce the energy lost through respiration
36
how can a food web be simplified?
by getting rid of pests
37
what are methods of pest control?
use chemical pesticides, (which simplifies the food web and means less biomass is lost from crops), and biological agents can reduce the number of pests (less energy and biomass lost from crops)
38
how can respiration loss be reduced?
keep animals in pens which restricts their movement, keep pens indoors and warm so less energy is lost by generating body heat
39
how do pens increase the energy conversion rate?
movement restricted so less energy used in muscle contraction environment kept warm to reduce heat loss from the body feeding controlled so maximum growth with no waste predators excluded so no loss to other organisms in the food web
40
what is a natural ecosystem?
ecosystem that hasn't been changed by human activity
41
how do saprobionts perform extracellular digestion?
secrete enzymes, digest food externally, absorb nutrients that they need
42
what is a symbiotic relationship?
close relationship between 2 species where at least one benefits
43
what are mycorrhizae?
symbiotic relationships that fungi form with plant roots
44
how do fungi form symbiotic relationships with plant roots?
fungi are made of long thin strands (hyphae) that connect to a plant's roots hyphae increase the surface area of a plant's root system, which helps the plant to absorb ions from the soil that are usually scarce hyphae increase the uptake of water by a plant in turn the fungi obtains organic compounds from the plant
45
what percentage of the air is made of nitrogen?
78%
46
how can plants and animals obtain nitrogen?
microorganisms convert nitrogen gas into nitrogen containing substances which can be absorbed, plants and animals cannot absorb directly through gas exchange
47
what biological molecules are nitrogen found in?
proteins, ATP, nucleic acids
48
what is nitrogen fixation?
when nitrogen gas in the atmosphere is converted into nitrogen containing compounds
49
where can nitrogen fixation occur?
in nitrogen fixing bacteria in legume root nodules, and nitrogen fixing soil bacteria
50
what are the stages of the nitrogen cycle?
nitrogen fixation occurs where nitrogen gas is converted into a nitrogen containing compound, such as an amino acid, by nitrogen fixing bacteria ammonification occurs when saprobionts break down organic matter into ammonium then nitrification occurs where nitrifying bacteria converts ammonia to nitrite ions, then to nitrate ions, using nitrifying bacteria in the process finally, dentrification occurs, where nitrate ions are converted into nitrogen gas by dentrifying bacteria
51
how can the process of dentrification be less wasteful?
keep the soil well drained and aerated
52
how do plants obtain nitrate ions?
by active transport
53
how do animals obtain nitrate ions?
by eating and digesting plants
54
what are examples of molecules where phosphorus is found?
DNA, RNA, ATP, phospholipid bilayer
55
what form is phosphorus found in?
not a gas like most cycles- found in phosphate ion mineral form in sedimentary rocks
56
why is mycorrhizae beneficial?
increases the surface area for uptake of water and mineral ions acts as a sponge to hold water and minerals makes plants more drought resistant able to take up more inorganic ions
57
how do mycorrhizae impact the phosphorus cycle?
improve uptake of scarce ions such as phosphate
58
what are the stages of the phosphate cycle?
1) phosphate ions in the rocks are released into the soil by weathering 2) phosphate ions are taken into the plants through the roots 3) mycorrhizae increase the rate at which phosphorus can be assimilated 4) phosphate ions are transferred through the food chain 5) phosphate ions are lost from animals in waste products 6) when plants/animals die, saprobionts are involved in breaking down organic compounds, which releases phosphate ions into the soil for assimilation by plants 7) weathering of rocks releases phosphate ions into seas, lakes and rivers, which is taken up by aquatic producers 8) waste produced by sea birds= guano- conatins a high proportion of phosphate ions 9) guano retruns phosphate ions to the soil, and is often used as a natural fertiliser
59
how are nutrients lost when crops are harvested?
crops take in minerals from the soil as they grow, when they are harvested removed from where they are grown rather than dying and deomposing, minerals are not returned to the soil by decomposers, when animals are taken elsewhere to be slautered nutrients aren't replaced by their remains/waste products
60
what are artificial fertilisers?
inorganic- contain pure chemicals
61
what are natural fertilisers?
organic-include manure, composted vegetables and sewage sludge
62
what is leaching?
water soluble compounds in the soil are washed away
63
when is leaching more likely to occur?
if fertiliser is applied just before heavy rainfall
64
why do fertilisers leach?
more fertiliser is applied than the plants need/can use at a certain time
65
when are fertilisers used?
to replace the nitrate and phosphate ions when plants are harvested and removed from the nutrient cycles as crops
66
what are the stages of eutrophication?
mineral ions leached from fertilised fields stimulate the rapid growth of algae in ponds and rivers large amounts of algae block light from reaching the plants below plants die as they cannot photosynthesis enough bacteria feed on dead plant matter- more bacteria reduce the oxygen concentration by carrying out aerobic respiration fish/aquatic organisms die if there isn't enough dissolved oxygen

biology updated (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions