TOPIC 7 - ECOLOGY Flashcards
(79 cards)
1
Q
define habitat
A
the place where an organism lives
2
Q
define population
A
all the organisms of one species living in a habitat
3
Q
define community
A
the populations of different species living in a habitat
4
Q
what are abiotic factors?
A
non-living factors of the environment eg temperature
5
Q
what are biotic factors?
A
living factors of the environment eg food
6
Q
define ecosystem
A
the interaction of a community of living organisms (biotic) with non-living (abiotic) parts of their environment.
7
Q
what do plants compete for?
A
light, space, water and mineral ions (nutrients) from the soil.
8
Q
what do animals compete for?
A
space(territory), food, water and mates.
9
Q
what is interdependence?
A
each species depends on other species for things such as food, shelter, pollination and seed dispersal.
The interdependence of all the living things in an ecosystem means that any major change in the eco system can have far-reaching effects.
10
Q
give examples of abiotic factors
A
non-living factors such as: moisture level light intensity temperature carbon dioxide level (for plants) wind intensity and direction oxygen level (for aquatic animals) soil pH and mineral content.
11
Q
give examples of biotic factors
A
living factors such as: new predators arriving competition - one species might outcompete another so that the numbers are too low to breed. new pathogens availability of food.
12
Q
what re adaptions?
A
the features or characteristics that allow organisms to live in different environmental conditions are called adaptions.
13
Q
what can adaptions be?
A
structural
behavioural
functional
14
Q
what are structural adaptions?
A
these are features in an organism’s body structure - such as shape or colour.
eg animals that live in cold places, like whales, have a thick layer of blubber (fat) and a low surface area to volume ratio to help them retain heat.
15
Q
what are behavioural adaptions?
A
these are ways that organisms behave. Many species, eg swallows, migrate to warmer climates during the winter to avoid problems of living in cold conditions.
16
Q
what are functional adaptions?
A
these are things that go on inside an organism’s body that can be related to processes like reproduction and metabolism.
Eg desert animals conserve water by producing very little sweat and small amounts of concentrated urine.
brown bears hibernate in winter. They lower their metabolism which conserves energy, so they do not have to hunt when there is not much food around.
17
Q
What are extremophiles?
A
Some microorganisms (eg bacteria) are adapted to live in very extreme conditions. For example, some can live at high temperatures and others can live in places with a high salt concentration or at high pressure, eg deep sea vents.
18
Q
what are producers?
A
producers make their own food using energy from the sun. Eg green plants or algae - they make glucose by photosynthesis. When a green plant produces glucose, some of it is used to make other biological molecules in the plant. These biological molecules are the plants biomass - the mass of a living material.
19
Q
what is biomass?
A
Can be thought of as energy stored in a plant.
20
Q
what order does the food chain go?
A
producers
primary consumers
secondary consumers
tertiary consumers.
21
Q
how would a change in the availability of water affect the distribution of organisms?
A
The distribution of some animals and plant species in the tropics changes between the wet and dry season. Ie in the times of year where there is more or less rainfall, and so more or less water available. eg each year in Africa, large numbers of giant wildebeest migrate, moving north and then back south as the rainfall pattern changes.
22
Q
how does a change in temperature affect the distribution of organisms?
A
The distribution of bird species in Germany is changing because of a rise of average temperatures. E.g. the European bee-eater bird is a Mediterranean species but it is now present in parts of Germany.
23
Q
how does a change in the composition of atmospheric gases affect the distribution of organisms?
A
The distribution of some species changes on areas where there is more air pollution. E.g. some species of lichen can’t grow in areas where sulfur dioxide is given out by certain industrial processes.
24
Q
what can environmental changes be caused by?
A
seasonal factors
geographic factors
human interactions
25
what is the water cycle?
energy from the sun makes water evaporate from the land and sea, turning it into water vapour. Water also evaporates from plants - this is known as transpiration.
The warm water vapour is carried upwards because warm air rises. When it gets higher up it cools and condenses to form clouds.
water falls from the clouds as precipitations onto land, where it provides fresh water for plants and animals.
It then drains into the sea, before the whole process starts again.
26
how are elements cycled back to the start of the food chain by decay?
living things are made of materials they take from the world around them. E.g. plants turn elements like carbon, oxygen, hydrogen and nitrogen from the soil and the air into complex compounds (carbohydrates, proteins and fats) that make up living organisms. These get passed up the food chain.
These materials are returned to the environment in waste products, or when organisms die and decay.
Materials decay because they are broken down (digested) by microorganisms.
Decay puts stuff that plants need to grow back into the soil eg mineral ions.
In a stable community, the materials that are taken out of the soil are used by plants are balanced by those put back in. There is a constant cycle happening.
27
when does decay happen quickest?
warm, moist and aerobic conditions.
28
what happens during the carbon cycle?
co2 is removed from the atmosphere by green plants and algae during photosynthesis. this carbon is used to make glucose, which can be turned into carbohydrates, proteins and fats that make up the bodies of the plants and algae.
When the plants and algae respire, some carbon is returned to the atmospere as co2.
when they are eaten, the carbon moves through thr food chain.
when the animals respire, the carbon is returned to the atmosphere as co2.
when plants, algae and animals die, other animals (called DETRITUS FEEDERS) and microorganisms feed on their remains. When these organisms respire, c02 is returned to the atmosphere.
animals also produce waste that is broken down by detritus feeders and microorganisms.
so the carbon (and energy) is constantly being cycled.
29
what is compost?
decomposed organic matter that is used as a natural fertiliser.
30
what microorganisms are responsible for decay?
bacteria
fungi
detritus feeders
31
how does temperature affect the rate of decay?
warmer temperatures make things decompose quicker because they increase the rate that enzymes involved in decomposition work at. if it gets too hot, the rate slows down or stops because the enzymes are destroyed and the organisms die.
32
how does availability of oxygen affect the rate of decay?
many organisms need oxygen to respire, which they need to do to survive. the microorganisms involved in anaerobic decay don't need oxygen though.
33
how does water availability affect the rate of decay?
decay takes place faster in moist environments because the organisms involved in decay need water to carry out biological processes.
34
how does the number of decay organisms affect the rate of decay?
the more mircrorganisms and detritus feeders there are, the faster decomposition happens.
35
how is biogas made?
biogas is made by anaerobic decay of waste material.
biogas is mainly made up of methane, which can be burned off as a fuel.
Different mircrorganisms decay waste anaerobically.
Sludge waste from, for example, sewage works or sewage factories, is used to make biogas on a large scale.
It is made in a simple fermenter called a digester or generator.
Biogas generators need to be kept at a constant temperature to keep the microorganisms respiring away.
Biogas can't be stored as a liquid (it needs too high a pressure), so it has to be used straight away - for heating, cooking, lighting, or to power a turbine to generate electricity.
36
How do biogas batch generators work?
Make biogas in small batches. They are manually loaded up with waste, which is left to digest, and the by-products are cleaared away at the end of each session.
37
How do biogas continuous generators work?
Make biogas all the time. Waste is continuously fed in, and biogas is produced at a steady rate. Continuous generators are more suited to large-scale biogas projects.
38
What is biogas used for?
Heating, cooking, lighting, or to power a turbine to generate electricity.
39
Why does biogas have to be used straight away?
It can't be stored as a liquid because it needs a too high pressure.
40
What do biogas generators need?
an inlet for waste material to be put in
an outlet for the digested material to be removed through
an outlet so that the biogas can be piped to where it is needed.
41
What is biodiversity?
The variety of different species of organisms on Earth, or within an ecosystem.
42
Why is biodiversity important?
It makes sure that ecosystems are stable because different species depend on each other for things like shelter and food. Different species can also help to maintain the right physical environment eg the acidity of the soil.
43
What is a reason for the increase in human population?
Modern medicine and farming methods, which has reduced the number of people dying from disease and hunger.
44
What impact does the increasing population have on the environment?
Puts pressure on the environment, as we take the resources we need to survive.
Use more raw materials due to higher standards of living.
Using non-renewable resources.
45
How does pollution affect water?
Sewage and toxic chemicals from industry can pollute lakes, rivers and oceans, affecting the plants and animals that rely on them for survival. The chemicals used on land eg pesticides can be washed into water.
46
How does pollution affect land?
We use toxic chemicals for farming eg pesticides. We also bury nuclearwaste underground, and we dump a lot of household waste in landfill sites.
47
How does pollution affect air?
Smoke and acidic gases released into the atmosphere can pollute the air E.g. sulfur dioxide can cause acid rain.
48
What do greenhouse gases do?
Carbon dioxide and methane trap energy from the sun and re-radiate it in different direction to keep us warm.
49
What are the consequences of global warming?
Higher temperatures cause seawater to expand and ice to melt, causing the sea level to rise. = flooding.
Changes in the distribution of animals and plants as the temperature increases and the amount of rainfall changes in different areas. Some species may become more widely distribution eg the warmer conditions allow them to spread further (opposite for colder conditions).
Changes in migration patterns E.g some birds might migrate further north, as more northern areas are getting warmer.
Biodiversity could be reduced if some species are unable to survive a change in the climate, so become extinct.
50
Why does deforestation occur?
To clear land for farming to provide more food
| To grow crops from which biofuels based on ethanol can be produced.
51
What probelems can deforestation cause?
Less carbon dioxide taken in - photosynthesis is reduced
More carbon dioxide in the atmosphere - carbon dioxide is released when trees are burnt to clear land. Also, microorganisms feeding on dead wood release carbon dioxide as a waste product of respiration.
Less biodiversity - habitats are destroyed.
52
What are peat bogs?
Bogs are areas of land that are acidic and water logged. Plants that live in bogs do not fully decay when they die because there is not enough oxygen. The partly-rotted plants gradually build up to form peat. So the carbon in the plants is stored in the peat instead of being released into the atmosphere.
53
What happens when peat bogs are destroyed?
Peat bogs are often drained so that the area can be used as farmland, or the peat is cut up and dried to use as fuel. Peat is used faster than it forms.
When peat is drained, it comes into more contact with air and some microorganisms start to decompose it. When these microorganisms respire, they use oxygen and release carbon dioxide, contributing to global warming.
Carbon dioxide is also released when peat is burned as a fuel.
Also reduces biodiversity.
54
How do breeding programmes protect ecosystems and biodiversity?
Helps to prevent endangered species from becoming extinct. Animals are bred in captivity to make sure the species survives. Individuals can sometimes be released into the wild to boost or re-establish a population.
55
How do protection and regeneration programmes protect ecosystems and biodiversity?
Look after rare habitats such as mangroves, heathland and coral reefs. Protecting these habitats also protects the species that live there. This preserves biodiversity.
56
How does introduction of field margins and hedgregrows protect ecosystems and biodiversity?
Reintroduced around fields on farms where only a single type of crop is grown. Field margins are areas of land around the edges of fields where wild flowers and grasses are left to grow. Hedgegrows and field margins provide a habitat for a wider variety of organisms than could survive in a single crop habitat.
57
How do regulations protect ecosystems and biodiversity?
Some governments have introduced regulations and programmes to reduce the level of deforestation taking place and the amount of carbon dioxide being released into the atmosphere by businesses. This could reduce the increase of global warming.
58
How does encouragement protect ecosystems and biodiversity?
People are encouraged to recycle to reduce the amount of waste that gets dumped in landfill sites. This could reduce the amount of land taken over for landfill, leaving ecosystems in place.
59
Why can the maintainance of biodiversity be difficult?
Costs money. Governments may pay farmers subsidies to reintroduce hedgegrows.
Can come at a cost to people's livelihood. Eg people employed in the tree-felling industry.
There can be a conflict between protecting biodiversiity and protecting our food security. Eg certain organisms are seen as pests by farmers.
Development is important, but it can affect the environment.
60
How can food chains be divided?
Trophic levels. These are different stages of a food chain. They consist of one or more organisms that perform a specific role in the food chain.
61
What is trophic level 1?
Producers
| They make their own food by photosynthesis.
62
What is trophic level 2?
Contains primary consumers.
Herbivores that eat the plants and algae are primary consumers.
Herbivores only eat plants and algae.
63
What is trophic level 3?
Secondary consumers
Carnivores that eat the primary consumers are secondary consumers.
Carnivores are meat eaters.
64
What is trophic level 4?
Tertiary consumers
Carnivores that eat other carnivores (the secondary consumers) are tertiary consumers.
Carnivores that ahve no predators are at the top of the food chain, so they're always in the highest trophic level. They are known as APEX PREDATORS.
65
What is an apex predator?
A carnivore with no predators.
66
What are decomposers?
Break down uneaten remains and waste. E.g bacteria and fungi. They decompose any dead plant or animal material left in an environment.
They can do this by secreting enzymes that break down the dead stuff into small soluble food molecules. These then diffuse into the microorganisms.
67
What do pyramids of biomass show?
The relative mass of each trophic level. There is less enery and less biomass every time you move up a stage (trophic level) in a food chain. There are usually fewer organisms every time you move up a level too.
The big bar along the bottom shows trophic level one.
Biomass and energy are still decreasing as you go up the levels.
68
What happens to biomass between each trophic level?
Biomass is lost.
Not much biomass gets transferred from one level to the next. Only about 10% of the biomass is passed on to the next level.
69
Why is biomass lost between each level?
Organisms don't always eat every single part of the organism they are consuming. E.g. the bone.
Organisms don't absorb all of the stuff in the food they ingest. The stuff they don't absorb gets egested (released) as faeces.
Some of the biomass taken in is converted into other substances that are lost as waste. E.g. organisms use lots of glucose during respiration. Lots of waste products such as carbon dioxide, water or urea.
70
What factors affect food security?
Population increasing.
Changing diets.
Farming can be affected by new pests and pathogens, or changes in the environmental conditions, can lead to famine.
The high input costs of farming can make it too expensive for people in some countries to start or maintain food production.
In some places, there are conflicts that affect availability of food and water.
71
What is the issue with overfishing?
Fish stocks are declining on the oceans because we are fishing too much.
This means that there are less fish for us to eat, the ocean's food chains are affected and some species may disappear altogether. E.g. cod are disappearing from the North West Atlantic.
72
What can be done to maintain fish stocks?
Fishing quotas
| Net size
73
What are fish quotas?
there are limits on the number and size of fish that can be caught in certain areas. This prevents certain species being over fished.
74
How does net size help to prevent overfishing?
There are different limits of the mesh size of the fish net, depending on what is being fished. This is to reduce the number of unwanted and discarded fish. Using a bigger mesh size allows the unwanted ones to escape. It also means that younger fish will slip through the net, allowing them to reach breeding age.
75
How can food production be made more efficient?
Limiting the movement of livestock and keeping them in a temperature-controlled environment reduces the transfer of energy from livestock to the environment. This means that animals are using less energy to move and control their body temperature. This means that more energy is available for growth, so more food can be produced from the same input of resources.
Livestock can be factory farmed - kept in small pens.
Fish can be factory farmed in cages where there movement is restricted.
Some animals can be fed high-protein food to further increase their growth.
76
What is mycoprotein?
Food from fungi.
Using modern biotechnology techniques, large amounts of microorganisms can be cultured industrially under controlled conditions in large vats for use as a food source.
Mycoprotein is used to make high-protein meat substitutes for vegetarian meals. eg Quorn.
It is made from the fungus Fusarium, which is grown in aerobic conditions on glucose syrup, which it uses as food.
The fungal biomass is harvested and purified to produce the mycoprotein.
77
How can bacteria be engineered to produce human insulin?
A plasmid is removed from a bacterium.
The insulin gene is cut out of a human chromosome using a restriction enzyme. Restriction enzymes recognise specific sequences of DNA and cut the DNA at these points. The cut leaves one of the DNA strands with unpaired bases - this is called a 'sticky end'.
The plasmid is cut open using the same restriction enzyme - leaving the same sticky ends.
The plasmid and the human insulin gene are mixed together.
Ligase (an enzyme) is added. This joins the sticky ends together to produce recombinant DNA (two different bits of DNA stuck together).
The recombinant DNA is inserted into a bacterium.
The modified bacterium is grown in a vat under controlled conditions. You end up with millions of bacteria that produce insulin. The insulin can be harvested and purified to treat people with diabetes.
78
How could biotechnology and genetic modification be used in agriculture?
Help to produce genetically modified crops that are resistant to pests - improving crop yields.
Genetically modified to grow better in drought conditions - improving crop yield.
Some can be modified to provide more nutritional value. E.g. Golden rice has been genetically engineered to produce a chemical that is converted in the body to Vitamin A.
79
Why doesn't everyone agree with genetic modifications of crops?
People need to tackle poverty first, people are hungry because they cannot afford food, not because there isn't food around.
There are fears that some countries may become dependent on companies who sell GM seeds.
Sometimes poor soil is the main reason why crops fail, and even GM crops will not survive.
