6.3.1 Ecosystems Flashcards
(115 cards)
1
Q
define niche
A
the role of an organism within an ecosystem, the effects it has on other components of the ecosystem and the effects they have on it
2
Q
define population
A
a group of organisms of the same species living in the same place at the same time who can interbreed
3
Q
define community
A
the sum total of all living organisms of all species living in the same place at the same time
4
Q
define abiotic factor
A
the non-living physical and chemical factors in an ecosystem that affect a populations distribution and abundance
5
Q
define species
A
a group of organisms that are able to breed together to make fertile offspring and have the same morphology, anatomy physiology and behaviour
6
Q
define ecosystem
A
the interactions between all organisms, and their environment in a particular area
7
Q
define biodiversity
A
the variety of living organisms present in an area
8
Q
define biotic factor
A
an environmental factor caused by other living organisms that affect a populations distribution and abundance
9
Q
define habitat
A
the part of an ecosystem where a particular organism lives
10
Q
how are food chains and food webs useful?
A
they are a useful means of showing what different organisms eat and therefore energy flow
11
Q
how are food chains and food webs not useful?
A
they do not provide quantitative information whereas ecological pyramids do
12
Q
what are some problems with pyramids of numbers?
A
-no account is taken of size (biomass) e.g. one tree is given the same value as one aphid therefore they can look inverted
-the number of individuals is so great that it is impossible to represent them all accurately using the same scale e.g. one tree and one million aphids
13
Q
what do we use instead of pyramids of numbers?
A
pyramids of biomass
14
Q
why do we use pyramids of biomass instead of pyramids of numbers?
A
-they are more reliable
-it provides a quantitative depiction of a food chain when their biomass is measured
15
Q
what is biomass?
A
the total mass of the plants and/or animals in a particular place, it is also referred to as the dry mass of an organism
16
Q
why can we not easily measure the biomass of different organisms?
A
the water content varies in different organisms
17
Q
what are the units for the dry mass of organisms in a certain area?
A
gm-²
18
Q
what are the units for the dry mass of organisms in a certain volume e.g. the ocean?
A
gm-³
19
Q
how do you measure the drymass of an organism?
A
-organism has to be killed and dried out
20
Q
what is an issue with measuring the dry mass of organisms?
A
it is destructive so only small samples are taken, but then this is not representative of the population
21
Q
what are the problems with using the dry mass of an organism?
A
there will still be variability due to gut contents
22
Q
how is the problem of variability of gut contents overcome?
A
-by keeping the animals alive in containers without food so they empty their guts
-dissect the preserved animal and flush their opened gut
-“ash” dry worms leaving only mineral gut contents
23
Q
what is a major issue of using pyramids of biomass?
A
there can be an anomaly from pyramid of biomass with aquatic food chains
24
Q
why is there less biomass in producers that primary consumers?
A
Sample is made at a single point in time and plant biomass may very with season. Phytoplankton may also be reproducing quickly and so large turnover of biomass.
25
describe pyramids of energy
-most accurate representation of energy flow through an ecosystem
-collecting data can be difficult and complex
-data is collected in a given area in a set time
-results are more reliable that for biomass (as 2 organisms of the same biomass may store different quantities of energy)
26
how is the energy in a pyramid of energy measured?
with a bomb calorimeter which measures change in temperature of water whilst burning
27
name some abiotic factors
-water supply
-wind speed
-temperature
-oxygen concentration
-light intensity
-atmospheric humidity
-carbon dioxide concentration
-factors relating to the soil
-pH
-availability of inorganic ions
28
name some biotic factors
-feeding
-parasitism
-predation
-mutualism
-competition
29
define predation
one organism kills and eats another
30
define carbon dioxide concentration
affects photosynthesising plants
31
define wind speed
affects transpiration rate of plants and can greatly increase cooling effects if environmental temperature is low
32
define feeding
feeding of herbivores on plants
33
define water supply
affects all organisms
34
define pH
of water or soil which affects all organisms living in them
35
define parasitism
in which one organism lives in close association with an organism of a different species and does it harm
36
define light intensity
affects the rate of photosynthesis and the behaviour of animals
37
define oxygen concentration
affects any organism that respires aerobically
38
define mutualism
in which two organisms of different species live in close association, both benefiting from the relationship
39
define availability of inorganic ions
such as nitrate or potassium, affects growth of plants
40
define competition
when two organisms both require something that is in short supply
41
define temperature
this affects the rate of metabolic reactions in endothermic and ectothermic organisms
42
define factors relating to soil
known as edaphic e.g. aeration. size of soil particles, drainage and mineral content
43
define atmospheric humidity
affects rate of water loss by evaporation from an organisms body
44
what are the different ecosystem case studies that I must know?
-large tree
-playing field
-rock pool
45
what are the living components of a large tree?
-plants (moss, algae)
-animals (goats, birds, big cats)
-insects
-the tree itself
46
what biotic factors will affect a large tree?
-feeding
-parasitism
-mutualism
-competition
47
what are the abiotic factors affecting a large tree?
-wind speed
-light intensity
-soil factors
-rainfall
-carbon dioxide concentration
-temperature
48
what is a trophic level?
a stage in a food chain
49
what is a biome?
a large naturally occurring community of flora and fauna occupying a major habitat e.g. a rainforest
50
what are the living components of a playing field?
-insects
-plants (daisies, dandelions, ferns, moss, grass, trees)
-animals (rabbits, moles, birds, squirrels, foxes)
51
what biotics factors will affect a playing field?
-grazing
-competition for space, light intensity
-feeding
-parasitism
-mutualism
52
what are the abiotic factors affecting a playing field?
-light intensity
-temperature
-rainfall
-soil factors
-trampling
-mowing
-exposure
53
why does an abiotic factor often have a greater effect on plant species in an ecosystem than on animal species in an ecosystem?
-animals can migrate and move away to find shelter and water whereas plants can't move
-animals can also regulate their own body temperature
-they also eat a variety of foods so abiotic factors don't affect us as much
54
what are the living components of a rock pool?
-animals (crab, fish, starfish, shrimp)
-plants (seaweed)
-sheltered creatures (barnacles, limpits, snails)
55
what biotic factors affect a rock pool?
-feeding
-predation
-mutualism
-competition
56
what are the abiotic factors affecting a rock pool?
-salinity
-wave action
-tides affect desiccation and submersion
-slope
-light availability
-temperature
-humidity
-rainfall/freshwater runoff
57
what is a dynamic ecosystem?
constantly changing ecosystem
58
are any of the three specific ecosystems studied dynamic?
all ecosystems are dynamic
59
describe how energy transfer works in the ecosystem
-in most living cells ATP is the immediate energy source
-initial entry of energy into the ecosystem is by photosynthesis
-however, energy is lost at each trophic level (meaning less energy is available to higher levels so there are fewer consumers as you go up the food chain)
60
what is ecological efficiency?
the efficiency of transfer of biomass or energy between trophic levels
61
what does the rate of energy flow equal?
productivity
62
what does gross primary productivity equal?
rate at which plants convert light energy to chemical energy
63
what does net primary productivity equal?
remaining energy left for consumers after energy loss from the plant
64
how do you calculate the energy available to next trophic level?
net production= gross production - respiratory losses
65
why is it hard to calculate the efficiency of consumers?
-not all biomass is eaten e.g. roots/bones
-energy is lost as metabolic heat (movement/respiration)
-some organism parts are indigestible (egested- faeces)
-energy is lost as excretory products
66
how do you calculate ecological efficiency?
ecological efficiency= (energy available after transfer / energy available before transfer) x 100
67
draw a diagram to represent how energy flows in the ecosystem
*see paper flashcard*
68
what is biomass?
energy available for use in cells
69
why is less that 3% of sunlight converted to chemical energy in plants?
-some energy is reflected
-some energy is transmitted straight through the leaf
-energy is absorbed but not used by chlorophyll, some is used to evaporate water
-sunlight may miss leaves entirely
-some energy is lost during photosynthesis
-only certain wavelengths are absorbed by chlorophyll so many wavelength are wasted
-water availability can limit photosynthesis
70
what is primary productivity?
this is the rate at which light energy is transferred to chemical energy in plants
71
what is the key way to improve primary productivity?
improving the rate at which crop plants can photosynthesise and produce biomass, this is done by:
-altering the abiotic factors that can act as limiting factors for photosynthesis
-manipulating biotic factors can improve primary productivity
72
what is the gross primary productivity ? (GPP)
a measure of the rate at which light energy is captured by the photosynthetic parts of a plant during photosynthesis
73
what is R? (respiration)
the amount of the "fixed" energy that is then used by the plant to maintain metabolic reactions and then eventually lost as heat
74
what is the Net Primary Productivity?
the rate of production of the plants biomass that is then available for the primary consumers
75
what is secondary production?
-this is the rate at which an animal gains biomass, as a result of eating either a plant or an animal
-most farmer animals are herbivores
-this is the case because there's only one link in the food chain so less energy is lost
76
what is the equation for Net Primary Productivity?
NPP= GPP-R
77
what are the different abiotic factors that can be changed to improved primary productivity?
-light
-water
-temperature
-mineral availability
78
what are the different biotic factors that can be changed to improved primary productivity?
-competition
-damage by pests
79
how would you improve the abiotic factor light to increase primary productivity?
-in a greenhouse you can use lamps
-outside you plant earlier in the year so when it's fully grown it is summer
80
how would you improve the abiotic factor water to increase primary productivity?
-use sprinklers/irrigation systems
-plant drought resistant crops
81
how would you improve the abiotic factor temperature to increase primary productivity?
-controlled temperatures in greenhouses or use heat lamps
-plant earlier in year so when it's fully grown temperatures are warm
82
how would you improve the abiotic factor mineral availability to increase primary productivity?
-crop rotation
-plant legumes/nitrogen fixing
-use fertilisers
83
how would you improve the biotic factor competition to increase primary productivity?
-reduce competition with non crop plants by using weed killers
84
how would you improve the biotic factor damage by pests to increase primary productivity?
-insecticides
-GM crops
-biological control
-fungicides
85
give five methods humans can use to improve secondary productivity
-selective breeding
-feed animals antibiotics
-feed animals steroids
-harvest the animals just before they reach adulthood
-stop animals moving by keeping in tight pens
-keep animals in warm conditions
86
would it be more efficient to farm endotherms or ectotherms?
It would be more efficient to farm ectotherms as they use most of their energy for growth whereas endotherms use a lot of their energy to regulate their body temperature- so a lot of energy is wasted.
87
discuss the concerns people may have about modern farming techniques
-animal welfare (keeping them in pens is unethical)
-antibiotic resistance (by giving animals drugs when they don't need them)
-fertiliser use can lead to eutrophication
-pesticides can lead to bioaccumulation and kill organisms we don't mean to
-herbicides decrease biodiversity
88
why do carbon dioxide levels fluctuate in the atmosphere?
-localised levels fluctuate seasonally due to photosynthesis rate (lower in summer as more photosynthesis and higher in winter as less photosynthesis)
-photosynthesis only occurs during they day, removing carbon dioxide
-respiration occurs 24 hours a day adding carbon dioxide at a steady rate, therefore there are higher levels of CO2 at night
89
what are carbon sinks?
reservoirs of carbon
90
what are some abiotic carbon sinks?
limestone, fossil fuels, the oceans
91
what are some biotic carbon sinks?
humus, plants via photosynthesis
92
what are the biggest carbon sinks on Earth?
the oceans and sedimentary rock
93
how is carbon taken in by the oceans?
-carbon dioxide dissolves into the water at the surface
-phytoplankton use it for photosynthesis
-carbon is stored in the shells of marine creatures and in coral reefs
-these processes remove dissolved carbon dioxide from the water, maintaining a diffusion gradient into the water
94
what are the different ways to measure changes in carbon?
-thermometers
-coral reefs
-ice cores
-historical records
-dendrochronolgy
95
how do thermometers measure changes in carbon?
-many readings are possible, but may be errors
-location is important as not representative of a large area
-may not pick up slight changes
96
how do coral reefs measure changes in carbon?
corals survive in a specific temperature range and if temperature rises the coral becomes stressed and expels zooxanthellae which it needs to provide it with food and survive
97
how do ice cores measure changes in carbon?
can be used to tell us the composition of the air and give us an indication of what temperatures were like
98
how do historical records measure changes in carbon?
useful as a comparison to more modern methods
99
how do peat bogs measure changes in carbon?
-they are important carbon sinks
-draining or burning peat bogs release carbon dioxide back into the atmosphere
100
how does dendrochronology measure changes in carbon?
-tree ring dating
-many large vessels laid down in summer and few small vessels laid down in winter
101
what processes increase global carbon dioxide levels?
combustion and deforestation
102
what samples can be taken to study how the atmosphere has changed over time?
air bubbles in glaciers
103
which areas provide the major source of inorganic carbon for plants?
the atmosphere
104
what are the key 5 processes that occur in the carbon cycle?
-respiration
-photosynthesis
-feeding
-combustion
-decomposition
105
what affects the amount of carbon dioxide dissolved in the oceans?
changes in temperature
106
how does global warming affect the amount of carbon dioxide dissolved in the oceans?
higher temperatures means less carbon dioxide can be dissolved into the oceans so more CO2 is in the atmosphere which creates a positive feedback loop
107
in what form are carbon containing compounds transferred into a consumer?
carbon macromolecules such as carbohydrates, proteins and lipids
108
how do carbon containing compounds get transferred between organisms in a food chain?
feeding
109
how do plants take in carbon containig molecules?
through stomata
110
what process do plants carry out to convert carbon containing compounds to carbon containing organic molecules?
how do thermometers measure changes in carbon?
111
what is the organic molecule produced through photosynthesis then used for?
respiration and to make more proteins and lipids
112
if carbon compounds are trapped where there are no decomposers what happens?
they become compacted to form fossil fuels
113
how are carbon compounds released from producers?
decay and respiration and consumption
114
how are carbon compounds released from consumers?
decay and respiration and consumption
115
what is the role of a decomposer in the carbon cycle?
to break down dead organic material and release CO2 through respiration
