Topic 5- On The Wild Side Flashcards
(60 cards)
1
Q
Definition of succession?
A
The gradual directional change of an ecosystem over time.
2
Q
Definition of primary succession and example?
A
Primary succession is when newly formed or newly exposed land which has no soil or organic material is inhabited by an increasing number of species.
E.g volcanic eruptions create new rock surfaces or sea levels drop exposing new land areas.
3
Q
Definition of secondary succession?
A
When a community is damaged by the soil and minerals are left over so plants can recolonise e.g a felled woodland
4
Q
Definition of climax community?
A
The end point of succession
5
Q
Definition of pioneer species?
A
Primary colonisers, adapted to harsh conditions e.g lichen
6
Q
Why is lichen a good pioneer species?
A
It has a mutualistic relationship between fungus and alga. Fungus is for protection and alga is for photosynthesis.
7
Q
What are the 6 steps of primary succession?
A
- Seeds and spores are blown in on the wind and the pioneer species arrives and colonises the area.
- The abiotic conditions are hostile as there is no soil to retain water so only the pioneer species can grow as they are specially adapted to cope with the harsh conditions e.g marram grass can grow in sand dunes new the sea as they have deep roots to reach the water and tolerate the salty conditions.
- The pioneer species changes the abiotic conditions by breaking up the rock and dying so micro organisms decompose the dead organic material (humus) to form a basic soil.
4.This makes the conditions less hostile as the basic soil helps to retain water allowing new organisms with different adaptations to move in and grow via seed dispersal. The roots of these small plants form networks which stabilise the soil and prevent it from being washed away. These also die and decompose adding more organic material deepening the soil and the mineral richness. Larger plants like shrubs can now start to grow in the deeper soil which can retain even more water.
- New larger and taller species like trees can now colonise the area but they may change the conditions to be less suitable to the previous species e.g changing abiotic factors like light intensity/exposure. These larger species out compete existing species becoming the dominant species.
- The climax community is reached which is not always the most biodiverse but it is stable and is usually made up of trees.
8
Q
Definition of dominant species?
A
Species that exerts overriding influence over others within a community.
9
Q
How are pioneer species adapted?
A
E.g groundsel
1. Seeds widely dispersed by wind
2. Rapid growth
3. Short lifecycle
4. Abundant seed production
10
Q
What are the 4 steps of secondary succession?
A
- Pioneer species colonise damaged lands, are larger than in primary as environment is more nutrient rich as there is already a layer of soil.
- Pioneer species die so soil becomes more nutrient rich and stable so other species colonise land and outcompete older species which causes shift in species present in ecosystem.
- As more species colonise the land, the complexity of the ecosystem increases and so does biodiversity.
- Climax community reached as ecosystem reaches equilibrium where species composition is no longer changing.
11
Q
What is deflected succession?
A
Where communities remain stable only because human activity prevents succession from running its course. E.g grazing.
12
Q
Definition of biosphere?
A
Part of the earth and its atmosphere inhabited by living organisms. E.g tropical rainforest, Mediterranean and tundra.
13
Q
Definition of habitat?
A
The place with a distinct set of conditions where an organism lives. 2 species can only share the same habitat if they occupy 2 different niches.
14
Q
What is a microhabitat?
A
Exists within a habitat like the bark of a tree.
15
Q
Definition of population?
A
Group of interbreeding individuals from the same species occupying the same habitat.
16
Q
Definition of community?
A
Multiple populations of different species sharing a habitat or ecosystem
17
Q
Definition of community?
A
A functional unit that tends to be fairly self sustaining comprised of communities, biotic and abiotic factors.
18
Q
Why can ecosystems be hard to define their boundaries?
A
This is due to ecotones which are areas between 2 ecosystems which have characteristics of both.
19
Q
Biotic factors are usually..
A
Density dependent which means that their effects are related to population size in a specific area. E.g predation, intra and inter specific competition and niches.
20
Q
What are abiotic factors?
A
Non living physical and chemical factors that affect an ecosystem. E.g climate, solar energy input, topography and empathic (soil) factors.
21
Q
What are abundance and distribution controlled by?
A
Abiotic and biotic factors like predation
22
Q
What are anthropogenic factors?
A
Arise from human activity and can be biotic or abiotic. Most ecosystems are no longer natural
23
Q
What is zonation?
A
The distribution of plants or animals into specific zones according to environmental factors, each zone is characterised by a dominant species.
24
Q
What are the 4 pieces of evidence for climate change and what are each of them?
A
- Temperature records
- Temperature has been measured using thermometers since the 1850’s around the world.
- This gives a reliable but short term record of global temperature changes.
- Weather is variable though so it is important to look at data over many years rather than just one year. - Dendrochronology:
- This is a method of figuring out the age of trees using tree rings.
- Most trees produce a new ring every year as they produce a new layer of xylem
- The oldest ring is in the middle so count inwards
- The width of the rings depends on the season/climate e.g rings are thicker when the conditions are warmer
- Can analyse by linking the width to climate conditions for that year. - Peat bogs:
- They can be used to measure change in temperature over thousands of years so go back further than temperature records.
- Pollen is often preserved in peat bogs due to their aerobic and acidic conditions which prevent decay.
- They accumulate in layers so the further down you go, the older the peat.
Scientists can analyse peat bogs by: - Taking a core of the peat bog and extracted pollen from different aged layers and identifying the species of plant.
- Only fully grown plants can produce pollen so the samples only show species that were successful at that time.
- Scientists know which climates plants live in now so findings pollen from a similar plant suggests the climate was similar to how it is now.
- A gradual increase in pollen from plant species who prefer warmer climates therefore provides evidence for temperature increase and can also be used to find out moisture levels.
- Carbon dioxide levels:
- As ice freezes, bubbles of air get trapped inside.
-Scientists can take ice cores and analyse the composition of gas bubbles to find out co2 concentration during that time.
25
What is the point about correlation does not equal causation for global warming?
Correlation does not equal causation but together with what we know about carbon dioxide as a greenhouse gas, this is strong evidence that carbon dioxide released by human activities since the Industrial Revolution is causing global warming.
26
What is the main factor which is causing climate change?
Anthropogenic = it is caused by human activities.
Human activity has caused global warming by enhancing the greenhouse effect which is the effect of greenhouse gases absorbing outgoing energy meaning less is lost to space.
The greenhouse gas effect is essential for keeping the planet warm however, too many greenhouse gases result in the planet being too warm.
27
What are the 5 stages of the greenhouse gas effect?
1. The sun emits short wave radiation in the form of UV and visible light.
2. This radiation is transmitted through the earth’s atmosphere.
3. Some of the radiation is reflected by the clouds back out into space.
4. Some of the radiation is absorbed by the earth’s surface causing it to be re-emitted as long wave infrared radiation (heat).
5. Some of this long wave IR is passed through the atmosphere and back into space which cools the planet, however some is absorbed by the layer of greenhouse gases which re-emit it in all directions trapping it within the atmosphere and therefore heating the earth up.
28
What are the 4 greenhouse gases?
1. CO2
2.NO2
3.Methane
4. Chlorofluorocarbon
29
What are the details of atmospheric methane?
Atmospheric methane has more than doubled since the mid 19th century.
It is continuously increasing due to increasing levels of methane being released from:
1. More fossil fuels being extracted/incombusted
2. More cattle so more methane being released as a waste product
3. Increasing temperatures are thawing permafrost which releases natural stores.
4. More decaying waste.
30
What are the details about atmospheric carbon dioxide levels?
Atmospheric carbon dioxide has fluctuated throughout history due to volcanic eruptions and limestone erosion but has reached its highest levels since the beginning of the Industrial Revolution.
It is increasing because:
1. Increasing amounts of fossil fuels like oil, coal, natural gas and petrol are being burnt/combusted for cars, transport and factories.
2. Natural sinks are being destroyed which removed CO2 from the atmosphere by storing it as organic compounds e.g trees are a large carbon sink but when destroyed and burnt, are releasing large volume of CO2 back into the atmosphere,
3. Additionally, increased levels of sulphur dioxide in the atmosphere creates increasing levels of acid rain which increases the rate of limestone erosion.
4. Increasing temperatures are thawing the arctic tundra and decomposing the Pete which releases CO2.
5. Finally, warmer water does not hold as much CO2 so the warming sea levels cannot hold as much.
31
What is extrapolation? (3)
Data that has already been collected on atmospheric greenhouse gases concentrations can be extrapolated to form predictions of how it will change in the future.
These predictions can be used to form models of how global climate will change.
Extrapolation is like extending a line on a graph.
32
What 2 things does making models from extrapolation assume?
1. We have enough data to establish trends currently
2. Current trends will continue
33
What are the 5 limitations of climate change models based on extrapolation?
1. We dont know how GHG emissions will change e.g we dont know which emission scenario is most accurate.
2. We dont know exactly how much emission scenarios will increase temperature by.
3. The change in atmospheric GHG emissions caused by natural causes is not known.
4. We dont know what attempts there will be to reduce GHG and how successful they will be.
5. We have limited knowledge about the complex climate change systems.
34
What is the main general way that global warming affects plants and animals?
Increasing temperate may affect the rate of enzyme activity.
35
What does an increase in temperature mean for enzyme activity normally and also when it’s too high?
Normally, the rate of enzyme controlled reactions will increase as temperature increases. More heat means more kinetic energy so the molecules will move around faster. This increases the likelihood of successful collisions between enzyme and substrate molecules. These collisions also have more energy so more likely to result in a reaction.
However, if temperatures are too high it can stop or slow down reactions altogether:
1. High temperatures causes the molecules to vibrate more
2. Too high of a temperature causes the vibrations to break some of the bonds holding the enzyme in shape.
3. This means the active site changes shape so that the substrate molecules no longer fit.
4. This enzyme is now denatured and can no longer act as a catalyst.
36
How does increased temperatures affecting enzyme reactions affect life cycle and development of organisms? (5)
This increase in temperature affects the metabolism of some organisms where reactions are controlled by enzymes.
So an increase in temperature may increase some organisms metabolic rates, increasing their rate of growth meaning they will develop and move through their life cycles faster.
E.g Cyanobacteria photosynthesise and produce toxins, so warmer waters may cause an increase in harmful algal blooms and increased production of toxins which are harmful to humans.
On the other hand, an increase in temperature may stop or slow down metabolic reactions leading to a slower life cycle and development.
E.g some plants like wheat may produce less yield in higher temperatures and cold water fish eggs may not hatch as they prefer cooler temperatures.
37
How does increased temperatures affecting enzyme activity result in change in distribution? (4)
Global warming may impact the distribution of some species as all species exist in places with ideal conditions for them. So if the conditions change, they will have to move to new areas with better conditions and if they cannot move they will die out.
E.g some conditions will become more common like more warmer areas causing butterflies and plankton to move up north where there are warmer seas and weather.
E.g or some conditions may become rarer like alpine plants are moving up mountains and polar bears habitats are shrinking due to melting ice caps which is causing increased competition within their habitat.
38
What are the other 2 climate changes that are affecting organisms? (4) (5)
1. Changing rainfall patterns:
- Also affects life cycle and distribution
- Some areas will receive less rainfall and some areas will receive more rainfall.
- Some species are not adapted for particularly dry or particularly wet areas so affects distribution as they will have to move otherwise they’ll die. E.g deserts may increase in area due to less rainfall.
- Some plants may remain dormant for longer (having increased life cycles and slower development) e.g desert plants remain dormant during dry seasons and after the first rain become active and grow new leaves.
2. Seasonal changes:
Phenology= the study of seasonal changes on animals and plants.
- This can also affect the life cycles and distribution of organisms.
- Temperature acts as a cue or a trigger for many development behaviours or changes.
- Many organisms rely on changing seasons for many things such as: flowering seasons, breeding/mating seasons and migration.
- For example, swallow live in Africa during the winter time and migrate to Europe in the spring to breed whilst there is maximum food availability. However, earlier British spring times mean that flowers and insects are produced earlier so that when the swallows arrive at their usual times, there is less food available. This causes less swallows to be born in Britain, and eventually the population that migrate to Britain will die out and their distribution will change.
39
What are the 3 consequences for the effects of climate change on life cycles, development and distribution? (4) (3)
1. Changes to communities:
Some species will cope better than others causing the balance between species to shift.
Those who benefit are more likely to become the dominant species.
However, other species may disappear from the community due to competitive exclusion from dominant or invasive species.
Non mobile species are particularly vulnerable and all of these things may lead to reduction in species richness.
2. Invasive species:
Species can change their distribution if the new climate conditions allow them to.
For example the swallows may change their distribution to further North of Europe, causing them to out compete native species and take over.
New increasing temps early in the year may lead to longer growing seasons but may also increase pests and disease prevalence.
3. Phenology mismatch hypothesis.
40
What is the phenology mismatch hypothesis?
1. Often egg hatching and adult emergence is synchronised with maximum food availability (e.g spring)
2. Some species lay eggs in response to photo periods (day length) and some grow in response to temperature.
3. So increasing temperatures= a change to growth rates leading to a mismatch between hatching times and food availability.
41
What is the scientific consensus about climate change?
The scientific consensus is that the increase in atmospheric co2 concentration IS causing an increase in global temperature.
42
What are some scientists saying against the scientific consensus of climate change?
And what can affect the conclusions that scientists draw? (3)
A handful of scientists have drawn other conclusions from the data suggesting that increasing atmospheric c02 concentration is not the main cause of climate change.
These conclusions can be affected by:
1. How good the data is (whether its reliable and valid)
2. How much evidence there is to support a theory
3. Bias- biased conclusions are not objective and have been influenced by opinion rather than purely scientific evidence.
43
What are 2 examples of why scientists may be biased?
1. Scientists working for oil companies are more likely to say that global warming is not being caused by humans in order to increase their sales
2. Scientists working for renewable energy companies are more likely to say that humans are causing global warming so that there is more sales of energy produced from the renewable energy sources.
44
There are strategies to reduce climate change but lots of different people have lots of different opinions causing a large debate. What are 4 viewpoints on increasing the use of biofuels?
1. Farmers support as the government sometimes funds the harvesting of crops for biofuels
2. Drivers support as biofuels are often a lots cheaper than oil based fuels.
3. Consumers oppose as the vast amounts of land used to grow biofuel crops may cause food shortages.
4. Conservationists oppose as forests are being cleared out for fields to grow biofuel crops.
45
There are strategies to reduce climate change but lots of different people have lots of different opinions causing a large debate. What are 4 viewpoints on increasing the use of wind turbines?
1. People working for companies making wind turbines support as their sales will increase
2. Environmentalists support as wind turbines do not release any CO2 into the atmosphere and still produce electricity
3. Local communities oppose as some people think that wind turbines ruin the natural landscape
4. Bird conservationists oppose as many birds are killed from flying into wind turbines
46
Draw the carbon cycle.
47
What are biofuels? (3)
1. Biofuels are a type of fuel made from biomass which is the material that is or was recently living.
2. Biofuels are often made from crops which can be replanted after being harvested which makes it a sustainable resource.
3. Biofuels are carbon neutral as they release the same volume of carbon when being burnt as they remove from the atmosphere when growing.
48
What is reforestation? (3)
1. Reforestation is the planting of new trees in existing forests that have been depleted.
2. More trees means more CO2 being removed from the atmosphere via photosynthesis.
3. Mature trees are able to remove a lot of CO2 by converting it into carbon compounds which are stored in plant cells in the trees making them carbon sinks.
49
What are the 4 disadvantages of biofuels?
1. They still release some carbon dioxide back into the atmosphere
2. The vast amounts of land used to grow the biofuel crops could have been used for food production.
3. Clearing land for biofuels often involves the loss of other important habitats which reduces biodiversity e.g rainforests.
4. Cutting down mature trees reduces the removal of C02 from the atmosphere via photosynthesis.
50
What are the other 4 types of renewable energy?
1. Wind turbines
2. Geothermal power
3. Solar power
4. Hydroelectric
51
What is the main existing mechanism of removing CO2 from the atmosphere and how can it be increased?
Photosynthesis is the main existing mechanism of removing CO2 from the atmosphere and can be globally increased by:
1. Allowing trees to grow to maturity as they can store large amounts of carbon in their biomass.
2. Planting new trees by reforestation
3. Stopping the destruction of forests by deforestation.
52
How does isolation lead to speciation?
How may reproductive isolation occur?
Speciation occurs when populations of the same species become reproductively isolated which reduces gene flow between the populations. This allows natural selection to act on the populations separately leading to the development of new species.
Reproductive isolation may occur due to geographical isolation (allopatric speciation) or from random mutations which cause a change in phenotype which prevents the populations from breeding (sympatric speciation).
53
What is the definition of allopatric speciation?
Allopatric speciation occurs when populations of the same species become separated by geographical barriers.
54
What is the definition of sympatric speciation?
Sympatric speciation is when populations of a species become reproductively isolated without geographical separation. So can occur due to random mutations which accumulate like behavioural, mechanical or seasonal.
55
Where does new evidence for evolution come from and what are the 2 types?
Molecular biology
Genomics and proteomics
56
What is the definition of genomics?
Genomics uses DNA technology to determine the base sequence of an organisms genome and the functions of its genes. This allows scientists to make comparisons between the DNA of organisms.
57
What are the 4 steps explaining genomics?
1. The theory of evolution suggests that all organisms evolved from a shared common ancestor
2. Closely related species diverged (evolved to be different species) more recently.
3. Evolution is caused by a gradual change in base sequence of an organisms DNA
4. Organisms who diverged more recently should have more similar DNA as less time has passed for changes in DNA to occur.
58
What is the definition of proteomics?
Proteomics is the study of proteins i.e the shape size and amino acid sequence of proteins.
59
What is the 3 steps explanation of proteomics?
1. The amino acid sequence of a protein is coded for by the DNA sequence of a gene.
2. More closely related organisms have similar DNA sequences and so will have similar amino acid sequences of a protein.
3. Organisms who diverged more recently should have more similar proteins as less time has passed for changes to occur.
60
What is the 5 step applied primary succession example to bare rock becoming a woodland?
1. Pioneer species colonise the rock e.g lichen grow and break down the rock releasing minerals.
2. Lichen dies and is decomposed helping to form a thin layer of soil which thickens as more organic material is formed. Allowing other species such as mosses to grow.
3. Larger plants who require more water can move in as the soil deepens e.g grasses and small flowering plants. The soil continues to deepen as these die and are also decomposed.
4 Shrubs, ferns and trees begin to grow and outcompete the grasses and smaller plants to become the dominant species which increases diversity.
5. Finally, the soil is deep and rich enough in nutrients to support large trees. These become dominant species and climax community is reached.
