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On the Wild Side Flashcards

1
Q

Define ecosystem

A

Community of living organisms and their environment in an area which is self-sustaining

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2
Q

Define habitat

A

place where an organism lives

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3
Q

Define population

A

All the organisms of one species in a habitat

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4
Q

Define population size

A

The number of individuals of one species in a particular area

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5
Q

Define community

A

the various populations sharing a habitat

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6
Q

Define abiotic factors

A

non-living factors of the environment

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7
Q

Define biotic factors

A

living factors of the environment

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8
Q

Define distribution

A

Where a species is within a particular area

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9
Q

Why does population size vary?

A

Because of the abiotic factors
E.g. the amount of light, water or space

Because of the biotic factors
E.g. Interspecific competition, intraspecific competition and predation

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10
Q

What happens if the abiotic conditions are ideal for a species?

A

Organisms grow fast and reproduce successfully

E.g. when temp of a mammal’s surrounding is ideal for metabolic reactions to take place, they don’t use up as much energy maintaining body temp. More energy for growth and reproduction so population will increase.

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11
Q

Define interspecific competition

A

Competition between different species

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12
Q

Define intraspecific competition

A

Competition within a species

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13
Q

Explain intraspecific competition (5)

A

1) The population of a species increases when resources are plentiful
2) As population increases, they’ll be more organisms competing for the same amount of food and space
3) Eventually resources become limiting and population begins to decline
4) A smaller population means there is less competition for resources which is good for growth and reproduction so population grows
5) Carrying capacity is reached

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14
Q

Define predation

A

Where an organism kills and eats another organism. The population sizes of predators and prey are interlinked.

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15
Q

Why does distribution vary?

A

Because of abiotic factors
- Organisms can only exist where abiotic factors they can survive in exist
E.g. Some plants only grow on south-facing slopes in northern hemisphere ad solar input (light intensity) is greatest.

Because of biotic factors
- Interspecific competition, if 2 species are competing and one is better adapted the other is likely to be out-competed
E.g. the native red squirrel has disappeared from large areas as the grey squirrel has a better chance of survival because it’s larger and can store more fat for winter.

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16
Q

Define niche

A

The role of a species within it’s habitat

  • Its biotic interactions
    E.g. the organisms it eats and those its eaten by
  • Its abiotic interactions
    E.g. the oxygen it breathes in and the carbon dioxide it breathes out
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17
Q

How many species can occupy a niche?

A

1

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18
Q

Explain abundance in terms of the niche concept

A

Two species occupying similar niches will compete so fewer individuals of both species will be able to survive in the same area.

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19
Q

Explain distribution in terms of the niche concept

A

Organisms can only exist in habitats where all the conditions that make up their role exist.
E.g. the soprano pipistrelle bat feds on insects and lives in farmland, open woodland, hedge lands etc. It couldn’t exist in a desert because there would be different insects.

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20
Q

What do you look at to investigate populations of organisms?

A

Abundance
- Estimated by counting the number of individuals in samples taken or using percentage cover for plants

Distribution

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21
Q

How do you avoid bias in your results?

A

The sample should be random

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22
Q

When is it necessary to do a non-random sample?

A

When in habitats where there’s a lot of variety in the abiotic features and/or distribution of species in the habitat and you want to make sure all the different areas or species are sampled

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23
Q

What is systematic sampling?

A

A type of non-random sampling.
Samples are taken at fixed intervals, often along a line
E.g. quadrats placed along a transect in a habitat where the abiotic factors change gradually from one end of the sample to the other (environmental gradient)

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24
Q

What are the benefits of using a frame quadrat

A

Useful for quickly investigating areas with species that fit within a small quadrat

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25
How to calculate the percentage cover using a frame quadrat?
Count how much of the quadrat is covered by the plant (you count a square if its more than half covered)
26
What are transects?
A line to help find out how plants are distributed across an area. There are 3 types: - Line transects - Belt transects - Interrupted transects
27
What is a line transect?
A tape measure is placed along the transect and the species that touch the tape measure are recorded
28
What is a belt transect?
Data is collected along the transect using frame quadrats placed next to each other
29
What is a interrupted transect?
Instead of investigating the whole transect of either a line or belt, you take measurements at intervals
30
What is topography?
The shape and features of the earth's surface
31
What are edaphic factors?
Soil conditions
32
How can you measure dissolved oxygen levels in aquatic habitat?
Using a oxygen sensor
33
How can you measure humidity?
Using an electronic hydrometer
34
How can you measure rainfall?
Using a rain gauge
35
What is succession?
The process by which an ecosystem changes over time. The biotic conditions change as the abiotic conditions change
36
What is primary succession?
This happens on land that's been newly formed or exposed. There is no soil or organic material to start with, e.g. bare rock.
37
What is secondary succession?
This happens on land that's been cleared of all the plants but where the soil remains, e.g. after a forest fire or deforestation
38
What are the stages of succession?
1) Primary succession starts when a species colonise a new land surface (pioneer species) - seeds and spores are blown in by the wind and begin to grow - the abiotic conditions are hostile (only pioneer species grow as they're specially adapted to cope) 2) Pioneer species change the abiotic conditions as they die and microorganism decompose the dead organic material (humus). This forms basic soil 3) Makes conditions less hostile so new organisms with different adaptations move in and grow 4) These then die and are decomposed adding more organic material, making the soil deeper and richer in minerals 5) Larger plants such as shrubs can now grow in deeper soil 6) Some new species may change the environment so it becomes less suitable for previous species 7) Secondary succession happens in same way but soil layer is already there so succession starts at a later stage. - pioneer species are larger plants (e.g. shrubs) 8) At each stage, different plants and animals that are better adapted for improved conditions move in and out-compete the organisms already there. They become the dominant species. 9) The ecosystem becomes more complex - new species move in alongside existing species so biodiversity increases 10) The final stage is called the climax community - the ecosystem is supporting the largest and most complex community of plants and animals it can. - it won't change much more so is in a stable state
39
What determines what species make up the climax community?
The climate in the ecosystem
40
Define plagioclimax
When succession is stopped artificially
41
Define phosphorylation
Adding phosphate to a molecule | E.g. ADP is phosphorylated to ATP
42
Define photophosphorylation
Adding phosphate to a molecule using light``
43
Define photolysis
The splitting of a molecule using light energy
44
Define hydrolysis
The splitting of a molecule using water | E.g. ATP is hydrolysed to ADP
45
Define redox reactions
Reactions that involve oxidation and reduction
46
What do plants need energy for?
Photosynthesis, active transport, DNA replication, cell division and protein synthesis
47
What do animals need energy for?
Muscle contraction, maintenance of body temp, active transport, DNA replication, cell division and protein synthesis
48
What is photosynthesis?
The process where energy from light is used to break apart the strong bonds in H2O molecules.
49
Where is hydrogen stored in the breakdown of H2O?
Glucose. | Formed when hydrogen is combined with CO2.
50
Where does O2 go in the breakdown of H2O?
Into the atmosphere
51
How do plants release the energy stored in glucose?
Respiration
52
What is the immediate source of energy in a cell?
ATP
53
Describe how ATP is synthesized
1) During respiration, glucose is broken down 2) Phosphorylation of ADP uses energy from an energy-releasing reaction (e.g. breakdown of glucose in respiration) 3) The energy is stored as chemical energy in the phosphate bond 4) The enzyme ATP synthase catalyses this reaction
54
How does ATP get to the part of the cell that needs energy?
Diffuses
55
How is energy released from ATP?
1) It's broken down via hydrolysis into ADP and inorganic phosphate 2) Chemical energy is released from the phosphate bond and used by the cell 3) ATPase catalyses this reaction
56
What are coenzymes?
A molecule that aids the function of a enzyme. They work by transferring a chemical group from one molecule to another.
57
What coenzyme is used in photosynthesis?
NADP
58
What does NADP do?
Transfers hydrogen form one molecule to another so it can reduce or oxidise a molecule.
59
What are chloroplasts?
Flattened organelles found in plant cells where photosynthesis takes place. They have a double membrane called the chloroplast envelope.
60
What's the advantage of having a double membrane in chloroplasts?
Keeps the reactants for photosynthesis close to their reaction sites
61
What are thylakoids?
Fluid-filled sacs that are stacked up in the chloroplast into structures called grana. They have a large surface area to allow high absorption of light.
62
What is a granum?
A structure within the chloroplasts of plants that is made up of stacked thylakoids and contains the chlorophyll and is the site of the light reactions of photosynthesis
63
How are the grana linked together?
By bits of thylakoid membrane called lamella.
64
What is present in the thylakoid membranes?
Lots of ATP synthase to produce ATP in light-dependent reactions. Photosynthetic pigments.
65
What are photosynthetic pigments?
Coloured substances that absorb light energy needed for photosynthesis.
66
What is the stroma?
A gel-like substance in the inner membrane of the chloroplast and surrounds the thylakoids. Contains all the enzymes, sugars and organic acids required for light-dependent reactions. Also contains oil droplets (store non-carbohydrate organic material)
67
Describe the Calvin Cycle
1) CO2 enters leaf through stromata and diffuses into stroma of chloroplast 2) It combines with ribulose bisphosphate (RuBP). 3) Catalysed by RUBISCO 4) Gives unstable 6-carbon compound, quickly breaks down into 2 molecules of 3-carbon compound called glycerate 3-phosphate (GP) 5) Hydrolysis of ATP from LDR provides energy to turn 3-carbon compound, GP, into different 3-carbon compound called glyceraldehyde 3-phosphate (GALP) 6) This requires H+ ions which comes from reduced NADP. Reduced NADP is recycled to NADP 7) Some GALP is then converted to useful organic compounds (e.g. glucose) and some continues in the Calvin Cycle to regenerate RuBP 8) Two molecules of GALP can be used to make hexose sugar (6 carbon atoms), e.g. glucose 9) 5 out of 6 molecules of GALP produced aren't used to make hexose but to regenerate RuBP 10) Regenerating RuBP uses rest of ATP produced by light-dependant reaction
68
Where does the LDRs take place?
Thylakoid membranes of the chloroplast
69
Where does the LIRs take place?
Stroma of the chloroplasts
70
How do you make ATP?
From ADP and inorganic phosphate by a reaction called photophosphorylation
71
What is photolysis?
Splitting water into protons, electrons and oxygen
72
Why is the Calvin cycle also known as carbon dioxide fixation?
CO2 is fixed in a organic molecule
73
What is genomics?
Branch of science that uses DNA technology to determine base sequence of an organisms genome and the functions of its gene.
74
What is proteomics?
Study of proteins | E.g/ the size, shape and amino acid sequence
75
What is evolution?
A change in allele frequency in a population over time. It occurs by natural selection.
76
Explain evolution
1) Individuals in a population vary because they have different alleles. The different alleles are due to gene mutations. 2) This means some individuals are better adapted to their environment. 3) Individuals that have an allele that increases their chance of survival are more likely to survive, reproduce and pass on their genes than individuals with different alleles. 4) This means a greater proportion of the next generation will inherit the beneficial allele. 5) So they are more likely to survive, reproduce and pass on their genes 6) The frequency of the beneficial allele increases from generation to generation.
77
Explain how isolation leads to speciation
1) Speciation happens when populations of the same species become reproductively isolated which reduces gene flow between two populations. 2) This means that natural selection acts on each population separately so new species can develop. 3) Reproductive isolation may occur because of geographical isolation (allopatric speciation) or because of random mutations in phenotype that prevent populations from mating (sympatric speciation)
78
Explain allopatric speciation
1) Populations that are geographically separated will experience slightly different conditions 2) Populations will experience different selection pressures and so different changes in allele frequency could occur 3) Different alleles will be more advantageous in different populations 4) Natural selection will then act on these alleles, increasing the frequency of it 5) Allele frequencies will also change as mutations occur independently in each population 6) The changes in allele frequency will lead to differences accumulating in the gene pools of the separated populations, causing changes in phenotype frequencies 7) Eventually the populations become genetically distinct so individuals form different populations will have changed so much they wont be able to breed with each other to produce fertile offspring - they have become reproductively isolated. 8) They are now separate species
79
Example of abiotic factors
``` Solar energy input Climate Topography (altitude, slope, aspect, drainage) Oxygen concentration Edaphic (soil pH and mineral content) Pollution Catastrophes. ```
80
Example of biotic factors
``` Competition Grazing Predation Disease Parasitism Mutualism. ```
81
Define anthropogenic factors.
Human activity.
82
Describe succession.
Colonisation is led by a pioneer species. | The final species is the climax community.
83
Describe deflected succession
Remains stable due to human activity preventing succession
84
Define gross primary productivity
The rate at which energy is incorporated into organic molecules
85
Define autotrophs
Organisms that can make their own organic compounds from inorganic compounds
86
Define net primary productivity
The rate at which energy is transferred into the organic molecules making up cell biomass
87
What is the calculation for net primary productivity?
NPP = GPP - R
88
Describe light-dependent photosynthesis
Occurs in the thylakoid membrane. Light energy excites two electrons per chlorophyll to an excited energy state. Electrons travel down the electron transport chain via a series of redox reactions. Energy is lost to synthesis ATP in photophosphorylation. Electrons from PSII replace those from PSI. Photolysis occurs, producing oxygen gas, H+ ions and electrons. The electrons combine with NADP to form NADPH.
89
Describe light-independent photosynthesis
RuBP and CO2 catalysed by RuBISCO to form GP. NADPH oxidised to produce NADP and ATP is phosphorylated to produce ADP and Pi. GALP produced 2 GALP removed to form glucose Remaining GALP used to phosphorylate ATP to ADP and produce RuBP
90
Describe primary consumers
Herbivores. Heterotrophs that eat plant material.
91
Describe secondary consumers.
Carnivores. Eat primary consumers.
92
Describe tertiary consumers.
Eat other consumers.
93
Describe detritivores.
Primary consumers that feed on dead organic materials (detritus).
94
Describe peat bogs
Anaerobic and acidic. Plants all have different types of pollen. Pollen grains have a tough outer layer that is decay resistant. Peat forms in layers. Each plant has specific conditions.
95
Describe dendrochronology
Trees grow new layers of xylem vessels. New vessels grow in accordance to season. Wide vessels in spring, narrow vessels in summer
96
Describe DNA hybridisation
When DNA is heated, base pairs break. We can mix it to make a hybrid. Not all bases complementary base pairs. Hybrid DNA denatures at lower temperatures
97
Define profile sequencing
Compares sequence of bases in different species. Fewer differences are more common ancestors
98
Describe molecular clocks
Molecular change in DNA over time can be used. Evolutionary trees can be formed
99
Describe profiling
Restriction enzymes cut at specific sequences. Produces fragments that can be visualised in bands. If there are mutations, restriction enzymes will not cut DNA
100
Define allopatric speciation
Geographical isolation
101
Define sympatric speciation
Reproductive isolation
102
Describe ecological speciation
Live in different parts of the habitat
103
Describe temporal speciation
Reproduce at different times
104
Describe behavioural speciation
Do not respond to mating behaviour
105
Describe physical incompatibility
Physical issues with reproduction
106
Describe hybrid inviability
Do not survive long enough to reproduce
107
Describe hybrid sterility
Cannot reproduce
108
Describe the carbon cycle
``` Release: Combustion Deforestation Volcanic activity Sedimentation Increase in acid rain. ``` Remove: Sustainable resources. Reforestation

Biology (5 decks)

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