Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

[OBSELETE] Edexcel - A Level Bio > Topic 5 > Flashcards

Topic 5 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What does community mean?

A

All the organisms of different species that live in the same habitat and interact with each other.

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

What does ecosystem mean with an example?

A

All the organisms living in a particular area and all the

  • Abiotic factors (Soil type and Climate)
  • Biotic factors (Predation and Competition)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does population mean?

A

All the organisms of one species on one habitat

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

What does habitat mean?

A

The place where an organism lives (Rocky shore or field)

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

Explain This Diagram

A

Represents Topography
- Different altitudes affects climate
- Slope good drainage of water
- Aspect which direction the land faces
- Effects soil depth, sunlight and water levels
- Meaning different organisms will grow in different areas

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

List all the abiotic factors

A
  • Solar energy input
  • Topography
  • Climate
  • Oxygen Convcentration
  • Edaphic Factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is solar energy input and how does it effect organism distribution and population?

A
  • Determined by latitude, season, cloud cover and changes to orbit
  • Plants need photosynthesis for energy and germination
  • Animals use light as a cue for certain behaviours (Reproduction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is topography and how does it effect organism distribution and population?

A
  • Different altitudes affects climate
  • Slope good drainage of water
  • Aspect which direction the land faces
  • Effects soil depth, sunlight and water levels
  • Meaning different organisms will grow in different areas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is climate and how does it effect organism distribution and population?

A
  • Rainfall, Wind exposure, Temperature
  • Can effect plant growth (water) and seed distribution (wind)
  • Hot climates encourage organisms that can resist the high temp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Oxygen Concentration and how does it effect organism distribution and population?

A
  • Important for aquatic densities
  • Fast flowing streams are often better oxygenated than stagnant pools
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are endaphic factors and how does it effect organism distribution and population?

A
  • Factors connected with the Soil (Mineral Ion Concentration, pH)
  • Effected by geology which effects plant distribution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List Biotic Factors

A
  • Comptetition
  • Grazing
  • Predation
  • Disease
  • Mutualism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is competition

A
  • Competition for food , light, water and space
  • Can be interspecific or intraspecific
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are Grazing , Predation and disease examples of?

A
  • Examples of relationships between two organisms
  • Where one benefits from the others loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is mutualism

A

Where two organisms in a relationship both benefit

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

What are Anthropogenic factors?

A

Factors are arising from human activity which can be abiotic or biotic

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

How does niches account for organism abundance and distrabution?

A
  • A role of a species within its habitat including
    • biotic interactions - food and predators
    • abiotic interactions - O2 taken in and $CO2 released
  • Where each species have its own unique niche
  • Where multiple species compete for the same niche
    • They will compete for food sources
    • Meaning a reduction of individuals in both species
  • Niches also explain distribution where organisms can only exist in conditions where their role exists
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is succession?

A

The variety of predictable processes that occur over time in a community that occupy a certain area.

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

Where does primary succession start?

A

Starts in a newly formed habitat where there has never been a community (Rocky and lack of soil)

Colonisation may occur

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

What is the pioneer species?

A

Species that can survive under extreme conditions:

  • lack of water
  • lack of soil
  • Extreme climate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do pioneer species do?

A
  • These species would then break up the rock surface
  • Organic species would then accumulate forming soil
  • Changing conditions for future wind-blown moss spores
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the next stage of succession?

A
  • Mosses build up more organic matter in the soil
  • Allowing for shallow-rooted plants to germinate and survive
  • As conditions improve species which are taller can colonise
  • Introducing competition until the taller larger species replace the existing community (Climax community)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Explain ths diagram

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

What is secondary succession?

A

Where a previously occupied area is re-colonised after a disturbance that kills a substantial amount of its community (like a natrual distaster)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How are pioneer species adapted to their function?

A
  • Seeds widely dispersed by wind
  • Rapid growth
  • Short life cycle
  • abundant seed production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is deflected succession?

A

Where a community remains stable due to human activity preventing succession from continuing

For how grassland is kept at grassland for livestock or golf courses

Chalk grassland needs to be actively managed

  • To prevent succession
  • That results in a loss or change in biodiversity
  • This can be done through grazing or burning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is phosphorylation?

A
  • To add phosphate to a molecule

Such as ADP is phosphorylated to ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is photophosphorylation?

A

Adding phosphate to molecule using light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is photolysis?

A

The breaking down of a molecule using light energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the equation for photosynthesis?

A
  • The glucose then stored the energy around the plant until it is needed for respiration

Animals would gain glucose from animals or plants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How does photosynthesis work?

A

Photolysis of Water

  • Energy from the sun allows for the OH bonds in water to break
  • Producing hydrogen and water
  • Photolysis of water

Storing Hydrogen in Glucose

  • The reaction between hydrogen and carbon dioxide leads to it being reduced into glucose
  • Which can be stored further as starch or used for other molecules like cellulose for cell walls, fats, amino acids and nucleic acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

How do ATP and ADP come into play?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the conversion of ADP to ATP?

A
  • ADP is converted to ATP through phosphorylation
  • Using energy from an energy-releasing reaction (Such as the breakdown of the phosphate bond in glucose when respiring releasing chemical energy )
  • With the enzyme ATP Synthase catalysing the reaction
  • ATP then diffuses to wherever the cells need it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the conversion of ATP to ADP?

A

ATP to ADP

  • ATP then is hydrolysed back into ADP and inorganic phosphate
  • Chemical energy is released and used by the cell
  • ADP and Inorganic phosphate is recycled
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the structure of the chloroplast?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are thylakoids and how is it adapted to photosynthesis?

A

Thylakoids

  • Large Surface Area
  • Allowing for maximum light absorption
  • Stacked up into grana which links together with the thylakoid membrane
  • Thylakoid membrane contains ATP synthase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are photosynthetic pigments and how does it relate to photosynthesis?

A

Photosynthetic Pigments

  • Coloured substances that absorb light energy
  • Found in thylakoid membrane attached to protein
  • Protein + Pigment = Photosystem

Photosystem 1 = 700nm light waves, Photosystem 2 = 680nm light waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is stroma and how does it relate to photosynthesis?

A

Stroma

  • Contained in the inner membrane, surrounding thylakoids
  • Gel-like substance
  • Contains enzymes, sugars and organic acids
    Required for light-dependent reactions
  • Contains oil droplets (stores non-carbohydrate organic material)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is the electron transport chain

A

Electron transport chain (Embedded in the membrane)

  • Made up of proteins Connected together
  • Needs to connect to the different Photosystems so its compact
    • So that NADP can be reduced
  • Meaning that the transport chain is efficient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are light-dependent reactions?

A

Reactions that use energy from the light along with hydrogen to produce reduced NADP and ATP along with Oxygen

The oxygen produced is used in respiration or released into the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are light-independent reactions?

A

Reactions that use the reduced NADP and ATP to reduce carbon dioxide to carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are light-independent reactions?

A

Reactions that use the reduced NADP and ATP to reduce carbon dioxide to carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

How do light-independent and light-dependent reactions work together?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the step-by-step process of non-cyclical light-dependent reactions?

A
  1. Light energy raises two electrons in each chlorophyll molecule to a higher energy level (Excited state)
  2. Electrons leave the excited chlorophyll molecule to electron carrier molecules forming the electron transport chain.
  3. Electrons from PS2 chlorophyll pass from one carrier to the next through oxidation and reduction reactions losing energy.

The energy lost is used in the photophosphorylation (synthesis of ATP)
4. Electrons from PS2 replace those lost from the PS1 chlorophyll
5. Electrons lost from PS2 chlorophyll are replaced in order to the continuation of the flow of electrons in the transport chain
6. In thylakoid space, an enzyme catalyses photolysis to produce oxygen gas, hydrogen ions and electrons.

The electrons replace those that were emitted from the PS2 chlorophyll molecule (Step 4) meaning the **chlorophyll loses its positive charge

Photolysis** increases the $H^+$ concentration within the thylakoid space
7. Electrons from PS1 chlorophyll pass along electron transport chain to combine with NADP (Co-Enzyme) + $H^+$ to form reduced NADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are cyclical light-dependent reactions?

A
  1. Light hits the chloroplast and is absorbed by the PS1
  2. Electrons are excited and picked up by electron carrier molecules
  3. They are sent to reduce NADP to reduced NADP
  4. Any remaining electrons are sent back to PS1 and used again
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the overview of the light-independent reactions?

A
  • Takes place in the stroma of chloroplasts
  • Uses reduced NADP + ATP from light-dependent reaction
  • Carbon Dioxide is reduced to Carbohydrate
  • NADP acts as a hydrogen Carrier preventing hydrogen from reacting with oxygen released from photolysis
  • Creates GP then GALP
  • Which can form glucose (After many cycles)
  • The rest goes onto form RuDP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the Calvin cycle simplified?

A
  • Shows how carbon dioxide combines with a 5-carbon compound to form a 6-carbon molecule
  • The 6-carbon molecule breaks down into two 3-carbon compounds
    • Some of the **3-carbon compounds reduce to form carbohydrate
    Using energy from ATP + Hydrogen** from the reduced NADP created in a light-dependent reaction
    - Some of the 3-carbon compound and phosphate from ATP regenerate the original 5-carbon compound
48
Q

What is the Galvin Cycle in depth?

A

Carbon Fixation

  1. RuDP (5-carbon compound) left over from the previous cycle
  2. Reacts with carbohydrates formed from **REDUCED Carbon Dioxide (**1 carbon compound**)**
  3. Creating an Unstable 6 carbon compound

Reduction

  1. An unstable 6-carbon compound breaks down into ****2 GP molecules (3-carbon compound)****
  2. The GP molecules are then reduced by ****reduced NADP using ATP****
    1. Turing **NADPH into NADP**
    2. Turning ATP into ADP + Phosphate group

Regeneration

  1. This then forms ****2 GALP molecules (2 Carbon Compounds)****
  2. Where 1 carbon from 1 GALP molecule is set aside for the formation of glucose
  3. ATP is then used to form RuDP
    1. ATP turned into ADP + Phosphate group
49
Q

What is carbon fixation in the Calvin cycle?

A

Carbon Fixation

  1. RuDP (5-carbon compound) left over from the previous cycle
  2. Reacts with carbohydrates formed from **REDUCED Carbon Dioxide (**1 carbon compound**)**
  3. Creating an Unstable 6 carbon compound
50
Q

What is Reduction in the Calvin cycle?

A

Reduction

  1. An unstable 6-carbon compound breaks down into ****2 GP molecules (3-carbon compound)****
  2. The GP molecules are then reduced by ****reduced NADP using ATP****
    1. Turing **NADPH into NADP**
    2. Turning ATP into ADP + Phosphate group
51
Q

What is regeneration in the Calvin cycle?

A

Regeneration

  1. This then forms ****2 GALP molecules (2 Carbon Compounds)****
  2. Where 1 carbon from 1 GALP molecule is set aside for the formation of glucose
  3. ATP is then used to form RuDP
    1. ATP turned into ADP + Phosphate group
52
Q

How many cycles and how many ATP molecules and NADPH molecules are needed to form 1 Glucose molecule

A
  • 6 Cycles
  • 12 NADPH and 12 ATP for reduction of GP to GALP
  • 6 ATP for GALP to RUDP
  • 1 Glucose = 12 NADPH + 18 ATP
53
Q

What is the primary productivity of the ecosystem?

A

The rate at which energy is incorporated into organic molecules

54
Q

What are heterotrophs?

A
  • Organisms that obtain energy as ‘read-made’ organic matter
  • By ingesting material from other organisms
55
Q

What is the chain of consumers?

A

Chain Of Consumers

  1. Producer - PLants
  2. Primary consumers - Herbivores (heterotrophs)
  3. Secondary consumers - Carnivores
  4. Tertiary consumers - Carnivorous
56
Q

What are detritivores?

A
  • Primary Consumers feed on dead organic material called detritus
  • Like woodlice, earthworms and shrimps
57
Q

What are decomposers?

A
  • Species of bacteria and fungi
  • Feed on dead remains of organisms and animal species
  • Heterotrophs
  • Secretes enzymes + External digestion before absorption
58
Q

What does productivity depend on?

A
  • How much energy is captured by producers
  • How much is transferred to the higher trophic levels
59
Q

Why is energy transfer so inefficient in plants?

A

Energy Transfer in Plants

Light is lost through

  • Reflection
  • Energy is used in evaporating the water
  • Transmitted through the leaf
  • Some light hits the wrong photosystem
60
Q

What is the law of limiting factors?

A

Law of Limiting Factors

  • When a process is affected by more than one factor
  • Its rate is limited by the factor furthest from its optimum
61
Q

What are the limiting factors of photosynthesis?

A
  • Limited by temperature in cool condition
  • By the light in overcast conditions
62
Q

What is GPP?

A

GPP

The rate at which energy is incorporated into organic molecules made by organisms

Units = Energy per unit area per year

63
Q

What is the calculation involving GPP?

A
64
Q

What is NPP?

A

NPP

The rate at which energy is transferred into the organic molecules that make up new plant biomass

units are kJ m-2 yr-1

65
Q

How do you work out NPP?

A
66
Q

Why is energy transfer between levels inefficient?

A
  • transfer of energy from producers to primary consumers isn’t very efficient
  • only 2-10% of energy goes to making new herbivore biomass
  • not all available food gets eaten due to the limitations of animal feeding methods
  • some undigested food remains in faeces such as cellulose as there’s no enzyme to break it down so the energy it contains isn’t transferred
67
Q

Is the energy transfer more or less efficient compared to producers to primary?

A
  • It’s more efficient
  • As the primary (Herbivore) is eaten by the secondary consumers (carnivores)
  • Protein diet = easy digestion
  • Less biomass left in faeces
68
Q

Why does the amount of energy transferred from one level to another decrease?

A
  • Respiration transfers energy to the surroundings
  • Decomposers (bacteria and fungi) then take energy away from organisms
    • Carrying out respiration
  • Excreted through species
69
Q

Explain this diagram

A
  • Respiration transfers energy to the surroundings
  • Decomposers (bacteria and fungi) then take energy away from organisms
    • Carrying out respiration
  • Excreted through species
70
Q

Why are there no more than 4/5 trophic levels?

A

Since the energy transfer decrease between trophic levels there come a when there is insufficient energy remaining to support the trophic levels.

71
Q

What does this diagram show?

A

This diagram shows the difference in the efficiency of energy transfer between trophic levels in different ecosystems

72
Q

How do you work out Energy efficiency?

A

Net Productivity is the energy lost

73
Q

What is climate change?

A
  • A significant change in the weather of a region over a period of several decades
  • Includes natural variations
  • Global warming is a type of climate change
  • Global warming causes rainfall patterns and seasons cycles (different types of climate change)
74
Q

How does temperature show evidence for climate change?

A

Temperature

  • Measured through multiple thermometers around the globe
  • The reliable short-term global temperature change
75
Q

How does dendrochronology show evidence for climate change

A

Dendrochronology (Tree Rings)

  • The age of the tree through tree rings
  • One ring per year
  • Thickness depends on how suited the climate is for growth
    • Warmer = Thicker
    • Colder = Thinner
  • Core through the tree trunk then date the ring
76
Q

How does pollen in peat bogs show evidence of climate change

A

Pollen (Peat Bogs)

  • Peat bogs are acidic wetlands which preserve pollen
  • Peat pollens form in layers
  • Meaning the age of the peat pollen increased with pollen and depth
77
Q

What are anthropogenic causes and what is the knock-on effect

A
  • Anthropogenic causes are caused by human activities
  • Which then enhances the greenhouse effect where more outgoing energy is absorbed by greenhouse gases

**Fossil fuels release Carbon Dioxide, and Industrial farming releases methane****

78
Q

How does carbon dioxide relate to climate change?

A

Carbon Dioxide

  • Increased other 100ppm since the mid-19th cent
  • Due to the increase in fossil fuel burning
  • Increasing destruction of natural sinks
    • Storage of carbon-reducing carbon dioxide conc
    • Trees are large carbon dioxide sinks
79
Q

How does methane relate to climate change?

A

Methane

  • Doubled since the mid-19th cent
  • more methane released from
    • a by-product of fossil fuel extraction
    • increase in cattle from waste gas
    • released from natural stones (permafrost thaw releasing methane)
80
Q

Why does climate change remain controversial?

A
  • Science can only disprove theories
  • The hypothesis is proposed by explaining observations which are then tested
  • If the results aren’t as expected there can be alternative explanations
  • Incomplete knowledge of how the climate system works
  • Data collected for climate change has limitations
  • Meaning that people use this to dismiss any correlations between carbon dioxide emissions and rising climate change
81
Q

What is extrapolation?

A
  • Where the line of best fit is extended to predict data we currently don’t have
  • Makes assumptions that
    • There is a lack of data to establish the trend accurately
    • present trends continue
82
Q

What are the factors that influence climate change other than CO2 emissions?

A
  • Other greenhouse gases such as methane
  • Aerosols - extremely small particles or liquid droplets found in the atmosphere
  • The degree of reflection from those parts of the earth’s surface that is free of ice and snow
  • The fraction of the earth covered with ice and snow
  • The extent of cloud cover
  • Changes in the sun’s radiation
83
Q

Why are models not perfect?

A
  • Limited data
  • Limited knowledge of how the climate system works
  • Limitations in computing resources
  • Failure to include all factors affecting the climate
  • Changing trends in factors included
    • Faster than expected loss of snow and ice cover
    • Greater carbon dioxide emissions
84
Q

What do climate models predict for the UK

A
  • The UK has milder winters due to warm water coming from the gulf of Mexico to north-west Europe
    • North Atlantic surface water cools contracts and sinks
    • Which then flows deep below the ocean surface and eventually goes back to the Gulf of Mexico
  • The artic sheet is melting
  • The influx of freshwater into the North Atlantic
    • Freshwater starts to freeze and expand
    • Rises to the surface rather than sinking (unlike salt water)
  • Critical point Atlantic drift could break meaning no more warm water in the Gulf of Mexico
  • Leading to a drop in temperatures in the UK
85
Q

How does global warming effect enzymes?

A
  • Rise in temperature leads to more vibration of the enzyme molecule
  • Leading to bonds breaking that hold the enzymes shape
  • Meaning the active site is changed and will no longer fit the substrate so no enzyme substrate can be formed
  • Denaturing the enzyme rendering it useless
86
Q

How are life cycles effected by global warming?

A
  • Metabolism and chemical reactions will be sped up
  • Increasing rate of growth and development resulting in faster progression of the life cycle
  • Enzymes in plants would work faster resulting in an increase in the rate of photosynthesis
  • Cyanobacteria (algae) would photosynthesis faster
    • Releasing toxins harmful to human health
    • Leading to harmful algal blooms
    • Rapidly increasing population
    • Accelerated by warmer water
87
Q

How is development effected by global warming?

A
  • If temperature is too high
  • Reactions can slow down stunting growth
  • When temps reach 25 degrees fewer wheat grains fall as well as yield
  • Eggs of cold water fish would not develop and hatch in warm water
88
Q

How does global warming effect distribution of organisms?

A
  • Species exist in their ideal temperature
  • A change in temperature forces migration of animals
  • Changing the distribution and potentially loosing species if they are unable to move
89
Q

How does changing rainfall patterns effect animals and plants?

A
  • Global warming changing rainfall patters
  • Effects development and life cycle of organisms
    • Cotillo is a desert plant which is dormant during low rainfall and a reduction in rainfall would cause longer dormant periods
  • Distribution would also be effected
    • Where deserts can increase or reduce in size
    • Causing migration of some species or increased competition
90
Q

How does changes in seasonal cycles effect animals and plants?

A
  • Global warmings change the timings of the plants
  • Organisms have behavioural adaptations based on seas
    • Such as mating patterns
  • Will effect development and life cycles
    • Squirrels will give birth three weeks earlier due to availability of food
  • It would also effect distribution
    • As some migration patterns rely on seasonal changes such as birds moving to warmer climates in the winter
91
Q

What is genomics?

A
  • Branch of science
  • It uses DNA tech to determine the base sequence of an organism’s genome
  • As well as the functions of its genes
92
Q

How does genomics support the theory of evolution?

A
  • Theory suggests all organisms have evolved from shared common ancestors
  • Meaning closely related species diverged more recently
  • Where there have been gradual changes in the base sequence (which is what has been found)
93
Q

What is proteomics?

A
  • Study of the size, shape and amino acid sequence of proteins
  • The sequence of amino acids in a protein is coded by the DNA sequence
  • So related organisms should have similar amino acid sequences
  • Meaning organisms that have recently diverged from each other should have similar proteins
  • As less time has passed for changes to occur
94
Q

How does the scientific community validate theory?

A
  • Data is collected to prove a theory like genomics and proteomics
  • This data is then shared with scientists all around the world
  • Which is then either accepted or rejected by the community through discussion
  • To check whether the data is valid and reliable
95
Q

How are scientific journals used for sharing ideas?

A
  • Academic magazines where articles are published
  • Shares new theories, ideas and evidence with conclusions
  • Allowing other scientists to repeat experiments and see if they get the same result using the same methods
  • Where if the results are replicated repeatedly the evidence can be deemed reliable
96
Q

How does peer review allow for sharing of theories?

A
  • Before work gets published it undergoes peer review
  • Where other scientists in that area of research read and review their work
  • Where they check that the work is valid and supports the conclusion
  • Ensuring that any scientific publishing is at the highest possible standards
97
Q

How do conferences contribute to theory development?

A
  • Meetings that scientists attend so they can discuss each other’s work
  • Scientists that have found interesting results might be asked to present their findings
  • Allowing for other scientists to ask questions and discuss their work face to face
  • An easy way for the latest theories to be shared and discussed
98
Q

What is speciation?

A
  • The formation of a new species
  • Through an isolating mechanism preventing successful interbreeding between populations of a species
  • The reproductive isolation prevents gene flow
99
Q

What is allopatric speciation?

A
  • Populations are geographically isolated
  • Prevents groups from mating
  • Populations become reproductively isolated
100
Q

What is sympatric speciation?

A
  • Populations become reproductively isolated
  • In the same environment without geographical barrier
  • Due to other isolating mechanisms
101
Q

What are the steps in allopatric speciation?

A
  1. Geographical isolation (High mountain range, River)
  2. Groups can no longer interbreed
  3. Two groups will become less like each other due to different selection pressures
  4. Different mutations will accumulate independently in each population changing the allele frequencies
  5. Meaning that genetic drift will occur meaning the to groups cannot produce fertile offspring (two different species)
102
Q

How does sympatric speciation work?

A
  • Different behaviour, ecological and genetic barriers arise within a population causing reproductive isolation
  • Meaning no gene flow causing changes in allele frequency causing speciation
103
Q

What is ecological isolation?

A
  • Different parts of the habitat are occupied by the species
  • Where soil content could change the species
104
Q

What is temporal isolation?

A
  • Species exist in the same area
  • Reproduce at different times
105
Q

What is behavioural isolation?

A
  • Species exist in the same area
  • Do not respond to each other courtship
  • So mating calls do not work
106
Q

What is physical incompatibility?

A

The physical shape of the genitals prevents the reproduction of a species

107
Q

What is hybrid inviability?

A
  • Hybrids are produced
  • Doesn’t survive long enough to breed
108
Q

What is hybrid sterility?

A
  • Hybrids produced
  • Survives long enough to reproduce
  • But is unable to
109
Q

What is the steps in the carbon cycle?

A
  1. Carbon in CO2 is absorbed by plants during photosynthesis
  2. Carbon is passed to animals when they eat the plant and then to decomposers when they eat dead organic matter
  3. Carbon returned to the atmosphere as all living organisms carry out respiration, which produces CO2
  4. The dead organic matter ends up in places where there aren’t any decomposers
  5. Carbon in fossil fuels is released as CO2 when they are burnt (combustion)
110
Q

How is CO2 released and taken ?

A
111
Q

How do biofuels decrease atmospheric CO2?

A
  • Fuels produced from biomass made from crops which can be replanted
  • They are burnt to release energy producing carbon dioxide
  • Meaning there is no net increase in atmospheric CO2 preventing the increase in CO2
112
Q

What is the pros of biofuels?

A
  • Farmers support and governments fund the farming
  • Driver support as the price of biofuels usually lower than oil based fuels
113
Q

What is the cons of biofuels?

A
  • Consumers oppose as using land for biofuels could be used for food shortages
  • Conservationists might oppose strategy as forests have to be cleared to grow crop for biofuels
114
Q

What is the cons of biofuels?

A
  • Consumers oppose as using land for biofuels could be used for food shortages
  • Conservationists might oppose strategy as forests have to be cleared to grow crop for biofuels
115
Q

How does reforestation decrease atmospheric CO2?

A
  • Planting more trees in existing forests that have been depleted
  • More CO2 is removed through photosynthesis
  • CO2 converted into carbon compounds and stored in plant tissues

[OBSELETE] Edexcel - A Level Bio (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions