1
Q
what are some issues with pyramids of numbers?
A
1) no account is taken of size - one tree is given the same value as one aphid, therefore they can look inverted
2) the number of individuals is so great that it is impossible to represent them accurately on the same scale as the other species in the food chain
2
Q
how are pyramids of biomass better than pyramids of numbers?
A
they are more reliable, quantitative description of a food chain
3
Q
what is biomass?
A
the mass of all organisms
4
Q
what can biomass be measured in?
A
with gm-2 for an area like a grassland or g m-3 for a volume like a lake
5
Q
why are results from pyramids of energy more reliable than those for biomass?
A
two organisms of the same biomass may store different amounts of energy
6
Q
what is the immediate energy source in most living cells?
A
ATP
7
Q
what is initial entry of energy into the ecosystem done by?
A
photosynthesis
8
Q
what does it mean that energy is lost at each trophic level?
A
less energy is available to higher levels so there are fewer consumers as you go up the foodchain
9
Q
why is so little energy available for herbivores?
A
- only certain wavelengths of light are absorbed by chlorophyll so many wavelengths are wasted
- some light is reflected
- some passes straight through the leaf
- some light is absorbed by non-photosynthetic parts of the plant
- energy lost due to inefficiency of photosynthesis
- glucose made is used up in respiration
10
Q
what is ecological efficiency?
A
the efficiency of transfer of biomass or energy between trophic levels
11
Q
what is productivity?
A
rate of energy flow
12
Q
what is gross primary productivity?
A
rate at which plants convert light energy to chemical energy
13
Q
what is net primary productivity?
A
remaining energy left for consumers after energy loss from the plant
14
Q
what is net production?
A
gross production - respiratory losses
15
Q
how else is energy lost?
A
as metabolic heat
16
Q
what is the equation for ecological efficiency?
A
energy available after transfer / energy available before transfer x 100
17
Q
see IRL flashcard for diagram of energy flow through organisms and ecosystems
A
18
Q
what is a 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
19
Q
what is the definition of population?
A
a group of organisms of the same species living in the same place at the same time who can interbreed?
20
Q
what is the definition of a community?
A
the sum total of all living organisms of all species living in the same place at the same time
21
Q
what is the definition of abiotic factors?
A
the non living physical and chemical factors in an ecosystem that affect a populations distribution and abundance
22
Q
what is the definition of 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
23
Q
what is the definition of an ecosystem?
A
the interactions between all organisms and their environment in a particular area
24
Q
what is the definition of biodiversity?
A
the variety of habitats, communities and species in an area and the genetic diversity within populations. it includes diversity within species and of ecosystems
25
what is the definition of biotic factors?
an environmental factor caused by other living organisms that affect a populations distribution and abundance
26
what is the definition of a habitat?
the part of an ecosystem where a particular organism lives
27
what is predation?
when one organism hunts and kills another
28
what is parasitism?
when one organism lives in close association with an organism of a different species and does it harm
29
what is competition?
when two organisms both require something in short supply
30
what are the living components of a rock pool ecosystem?
- seaweed
- barnacles
- limpets
- crabs
- small fish
31
what biotic factors will affect a rock pool?
- predation
- competition for space and food
- symbiosis
- decomposition by microorganisms
32
what are the abiotic factors affecting rock pools?
- salinity
- temp
- sunlight
- water availability
33
what is a dynamic ecosystem?
an ecosystem that is constantly changing die to interactions between organisms and changes in environmental conditions
34
why does an abiotic factor often have a greater affect on plant species in an ecosystem than on animal species in an ecosystem?
plants rely directly on abiotic factors to survive and grow they cannot move to avoid unfavourable conditions. animals however can often move to escape harsh environments or find better resources, making them less directly affected
35
what is a trophic level?
a position an organism occupies in the food chain
36
what is a biome?
a large geographical area defined by its climate, soil and the living organisms adapted to it
37
what is an advantage of measuring wet biomass?
measures the fresh mass
38
what is the advantage of measuring dry rather than wet biomass? how is dry biomass obtained?
- water content varies
- it is dehydrated
39
what is a disadvantage of measuring dry biomass and what limitation is placed on the data as a result?
very destructive - small sample size - not representative
40
how can we exclude the gut contents from the dry biomass measurement and why would we want to?
leave organism for 24-48 hours to remove gut contents - starve it
41
what is primary productivity?
the rate at which light energy is transferred to chemical energy (biomass) in plants
42
what is the gross primary productivity (GPP)?
a measure of the rate of which light energy is captured by the photosynthetic parts of the plant during photosynthesis
43
what is R (respiration)?
the amount of 'fixed' energy that is then used by the plant to maintain metabolic reactions
44
what is the net primary productivity (NPP)?
the rate of production of the plants biomass that is then available for the primary consumers
45
what is secondary production?
the rate at which an animal gains biomass as a result of eating either a plant or animal
46
what is the equation for NPP?
GPP - R
47
what is the key way to improve primary productivity?
increasing the rate of photosynthesis
48
what are some biotic ways that humans can improve secondary productivity?
- selective breeding to improve growth
- feed animals antibiotics/steroids
- kill animals just before adulthood
49
what are some abiotic ways that humans can improve secondary productivity?
- keeping animals in tight pens
- keeping in warm condition
- reduce energy loss
50
would it be more efficient to farm endotherms or ectotherms?
- ectotherms
- they do not use energy to maintain a constant body temp, so more of the energy from food goes into growth rather than heat production
51
why does modern agriculture use selective breeding?
to produce animals and plants with desirable traits
52
why does modern agriculture use fertilisers?
provide essential nutrients to crops
53
why does modern agriculture use genetic modification?
introduce beneficial traits into organisms
54
why does modern agriculture use steroid hormones?
to promote faster growth in animals allowing them to reach market size
55
discuss the concerns people may have about modern farming techniques?
people may be concerned about the environmental impact, such as pollution from fertilisers and pesticides, loss of biodiversity and soil degradation
56
why is the carbon cycle important?
- one of the most significant elements
- in carbs, fats, proteins and nucleic acids
- main source of carbon is CO2 in the atmosohere
- constantly cycles between atmosphere and living organisms
57
how are corals affected by rising CO2?
- they have a specific temp range to live in
- if temp rises above this, coral bleaching occurs where the coral expels zooxanthellae (photosynthetic algae) it needs to provide it with food
- coral cannot survive without zooxanthellae
58
what process increases global carbon dioxide levels?
photosynthesis, combustion, decomposition, rspiration
59
what samples can be taken to study how the atmosphere has changed over time?
ice cores removed from deep inside glaciers - air bubbles trapped show composition
60
in what form are carbon containing compounds transferred into a consumer?
carbon-containing organic compounds e.g carbs, proteins, lipids and nucleic acids
61
how do carbon containing compounds get transferred between organisms in a food chain?
consumers eat either producers or other consumers
62
how do plants take in carbon containing molecules?
CO2 from atmosphere via stromata for photosynthesis
63
what process do plants carry out to convert carbon containing compounds to carbon containing organic molecules?
photosynthesis
64
what is the carbon containing organic molecule used for?
production of macromolecules
65
which areas provide the major source of inorganic carbon for plant?
CO2 dissolved in the atmosphere and dissolved in seas and oceans
66
what are the key 5 processes that occur in the carbon cycle?
- combustion
- decomposition
- respiration
- feeding
- photosynthesis
67
if carbon compounds are trapped where there are no decomposers, what happens?
carbon can become trapped in organisms that do not decay and form fossil fuels
68
what affects the amount of carbon dioxide dissolved in the oceans?
the amount of CO2 in atmosphere that dissolves in:
- combustion
- respiration
69
how does global warming affect the amount of CO2 dissolved in the oceans?
global warming means more CO2 will be dissolved into the oceans
70
why do carbon dioxide levels fluctuate through the day?
photosynthesis only occurs in the day, respiration is all the time, seasonal fluctuations
- CO2 lower in summer
71
how are carbon compounds released from producers?
respiration
72
how are carbon compounds released from consumers?
respiration
73
what is the role of a decomposer in the carbon cycle?
break down dead organic matter from plants and animals, CO2 released into the atmosphere as they respire
74
see IRL flashcard for diagram of carbon cycle
75
what are detritivores?
organisms that feed on detritus and breaks it into smaller pieces for decomposers
- e.g. woodlice and worms
76
what are decomposers?
organisms that feed on and breaks down dead plant/animal matter
- e.g. bacteria and fungi
77
what does nitrogen exist as?
- nitrogen gas (N2)
- dissolved in ocean
- ammonnia - phytoplankton (NH3)
- nitrite (NO2-)
- nitrate (NO3-)
78
what is nitrification?
when nitrite is converted into nitrate
79
what are the biological molecules made from nitrogen?
- proteins
- DNA
- RNA
80
what is decomposition (ammonification's)?
organic matter from death and excretion is broken down by saprotrophs
- bacteria and fungi
81
how do saprotrophs break down dead material?
they use extracellular digestion, secrete digestive enzymes and absorb these products
82
what is nitrification?
converts ammonium compounds in the soil into other nitrogen containing compounds that can be absorbed by plants
83
what is the process of converting ammonia to nitrate?
ammonia --Nitrosomonas--> nitrate --Nitrobacter--> nitrate
84
how can the nitrate ions be formed?
- be absorbed by plant roots and used by plants to make amino acids or nucleic acid
- be converted to nitrogen gas (denitrification)
- leach into deeper levels of soil and rivers
85
what happens in denitrification?
in waterlogged soils (which are anaerobic) certain anaerobic bacteria species have the ability to absorb and use nitrates as a source of oxygen (for aerobic respiration) and release (waste)nitrogen gas into the atmosphere
86
what is an example of denitrifying bacteria?
pseudomonas
87
what happens in nitrogen fixation?
converts gas to ammonium ions
88
what is nitrogen fixation carried out by?
- rhizobium bacteria - live inside root nodules of legume plants such as peas and clover. this is a symbiotic mutualistic relationship
- azotobacter - free living soil bacterium
89
what does nitrogenase enzyme do?
combines atmospheric nitrogen and hydrogen to produce ammonia (NH3)
90
what are other processes that can be included in fixation?
- lightning - converts nitrogen gas to nitrates
- produces sufficient energy to combine O2 and nitrogen in the air
- harper process - uses high pressures, temps and a catalyst to form ammonia fertilisers
91
what are some other processes in the nitrogen cycle?
- consumption - animals eat plant proteins, digest them and use the amino acids to produce their own proteins
- death of plants and animals
- excretion - removal of metabolic waste from the body e.g. urea
- assimilation - uptake of ammonium ions and nitrates and their incorporation into plant proteins and nucleic acids
92
what is succession?
a directional change in a community of organisms overtime
93
what are the two types of succession?
- primary succession
- secondary succession
94
what is primary succession?
the starting point e.g. bare ground, rock, lava, sand
95
what is secondary succession?
here a community is damaged and the soil if left. plants then colonise e.g. after a forest fire
96
what is the end points of both types of succession?
the climax community
97
what is a pioneer species?
the first species to colonise an area
- short lived opportunists
- able to withstand desiccation, extremes of temps and low levels of minerals
98
what is the process of a pioneer species developing?
1) pioneer species arrive e.g. lichens penetrate and break up rock
2) die and decompose
3) humus builds up
4) simple plants such as mosses (secondary colonisers) can grown if their seeds/spores arrive
5) these overshadow the pioneers which die
99
how does an intermediate community develop?
- roots of secondary colonisers are longer and so further break up the rock
- organic matter gradually increases as these bigger plants die
- more water is retained by the soil so grasses, small flowering plants and ferns (tertiary colonisers) can grow
100
how is a climax community reached?
when the area is eventually colonised by dominant plant species
101
what are the woodland seral stages?
- grasslands, small flowering plants
- grass, daisies
- taller, herbaceous plants
- willowherb, foxglove
- bushes and shrubs
- hawthorn, bramble
- fast growing trees
- birch
- larger, slow growing, stronger trees
- oak
102
what are nitromonas and nitrobacter?
bacteria that oxidise ammonium ions to nitrate and nitrite ions
103
what is excretion?
the removal of toxic waste products of metabolism
104
what is the Haber process?
an organism which gets its energy from non living organic matter. this may be decaying matter or waste materials
105
what is succession?
change in the composition or structure of an ecological community over time
106
what is a sere>
a stage in the process of succession
107
what is the lithosere?
bare rock
108
what is the psammosere?
bare sand
109
what is the hydrosere?
water
110
what can primary succession be summarised into (seral stages)
- migration
- colonisation
- establishment
- competition
- stabilisation
- climax
111
what is deflected succession (plagioclimax)?
- often a climax community is not reached
- this may be due to human activity such as agriculture
- can also be the result of one or more limiting factors in the local environment
112
what are some statements about pioneer species?
- are not able to compete for resources e.g light
- are not influenced by or dependent on animal species
- can tolerate extreme conditions
- species which are early arrivals
- have very good means of dispersal, usually by wind
- may be able to fix nitrogen and build up soil nutrient
113
what are some statements about climax community species?
- are strongly influenced by other organisms
- are unable to tolerate great fluctuations in the water content of soil
- have a specialised niche
- have larger seeds so that seedlings can survive low light intensity
- species found in the end point community
Biology
flashcards
Decks in class (26)
# Cards
-
Cell structures147
-
Biological Molecules233
-
Nucleic Acids48
-
Enzymes54
-
Plasma Membranes64
-
Cell division, cell diversity and cellular organisation138
-
Exchange Surfaces and Breathing97
-
Transport in Animals150
-
Transport in Plants72
-
Classification124
-
Biodiversity90
-
Disease243
-
Neuronal communication77
-
Hormonal communication104
-
Homeostasis55
-
Energy for biological processes98
-
Excretion119
-
Respiration118
-
Plant responses94
-
Animal responses72
-
Genetics And Living Systems61
-
Patterns of Inheritance and Variation72
-
Manipulating Genomes96
-
Cloning and biotechnology129
-
Ecosystems113
-
Population and Sustainability97
