Ecology Flashcards
1
Q
define ecosystem
A
The living organisms in a particular area, together with the non-living components of the environment.
2
Q
what 4 things do plants compete for and why?
A
- light- needed for photosynthesis
- water from the soil- reactant for photosynthesis
- minerals from the soil- for healthy growth (not get mineral defficiencies)
- space- for healthy growth
3
Q
what 3 things do animals compete for?
A
- food- to complete life processes, without which they may die
- mates- so they can pass on their
genes to their offspring - territory- territories of animals contain all of the resources and conditions they need to survive (biotic and abiotic)
4
Q
define and explain interdependence
A
- all organisms that live in an ecosystem depend upon each other, for food, protection, shelter, etc, in order to survive
- If the population of one organism rises or falls, then this can affect the rest of the ecosystem
- Often very small changes to ecosystems have large consequences, which can be difficult to predict.
5
Q
what is a stable community?
A
- one in which the size of the populations of all species remain relatively constant over time
- The different populations are living in a healthy balance with their environment.
6
Q
8 abiotic factors that affect communities/ organisms
A
- light intensity
- temperature
- moisture levels
- soil pH content
- soil mineral content
- wind intensity and direction
- carbon dioxide level for plants
- oxygen levels for aquatic animals
7
Q
4 biotic factors that affect communities/ organisms
A
- availability of food
- new predators
- new pathogens
- out-competition- introduction of a new species into an ecosystem can result in it out-competing another native species.
8
Q
what are the 3 types of adaptations of organisms?
A
- structural
- behavioural
- functional/ physiological
9
Q
what is a structural adaptation? give an example in plants and animals
A
- the physical features, which allow them to compete
- the formation of spines, which are found on many species, such as cacti and roses, and can stop a plant being eaten by grazing animals
- sharp claws to catch prey, dig burrows
10
Q
what is a behvioural adaptation? give an example in plants and animals
A
- behaviours which give them an advantage
- venus fly trap closing its trap to catch insects
- mating rituals, like a male peacock bird showing his tail feathers to attract a female mate. They can also include working together in packs like wolves to hunt prey
11
Q
what is a functional/ physiological adaptation? give an example in plants and animals
A
- processes which allow them to compete
- poisons for defence- nettle plant stings us when we brush the tiny needles on its leaves, which contain poison
- production of venom is an example of this. Many predators such as snakes and spiders produce venom both to defend themselves and kill their prey
12
Q
what is an extremophile?
A
- an organism that lives in an extreme environment.
- An extreme environment is one in which most organisms would find it difficult or impossible to survive.
- The organisms that live in these places have highly specialised
adaptations. - e.g. the Polar Regions, deserts, the deep ocean bed, hot geothermal springs and the tops of our highest mountains.
13
Q
define producer and state their position in the food chain
A
- Plants that begin food chains by making energy from carbon dioxide and water.
- base of almost every food chain
14
Q
define decomposer
A
An organism which eats dead organisms, fallen leaves, animal droppings, etc, and breaks them down into simpler materials.
15
Q
explain how quadrats are used
A
- Quadrats are square frames of wire usually 0.25 m2. These are placed on the ground to look at the plants or slow-moving animals within them. When looking at plants in a quadrat the following sampling can be used:
- Number of an individual species.
- Species richness
- Percentage cover
16
Q
explain how transects are used
A
- A quadrat could be placed at regular distances, for example every five metres, along an imaginary line called a transect, which would run down the shore.
- Systematic sampling would be used along the transect to link changes in
species to abiotic factors, such as immersion by water, temperature fluctuations, light intensity, all of which are influenced by the tide. - The results from transects can be drawn into kite diagrams. The width of the bar from the middle at any distance shows how many individuals were observed at that point.
17
Q
why do ecologists use quadrats and transects?
A
- Random sampling using a quadrat involves the placing of quadrats at random coordinates. Regardless of whether you are investigating the number of individual species, the species diversity or the percentage cover in different areas you would use random sampling.
- It is important to estimate the number of organisms in a population to better understand the relationships in a community for monitoring the impact of conservation projects that aim to conserve
endangered species or habitats It is almost always impossible to count all of the organisms in a population. So we look at a small section of a population to draw conclusions about the rest- sampling.
18
Q
what is a predator-prey cycle?
A
- graph that shows characteristic repeating patterns
- graph shows population size (Y) against time (X) with lines that represent the predator and preys population
- In a healthy, balanced ecosystem the numbers of predators and prey remain fairly constant.
- They can go up and down during each year due to biotic and abiotic but generally over the years, these increases and decreases remain fairly constant.
- a change in an abiotic/ biotic factor can result in a less healthy, balanced ecosystem.
19
Q
describe the process of the carbon cycle
A
- Carbon enters the atmosphere as carbon dioxide from respiration and combustion and is absorbed by producers to make carbohydrates in photosynthesis. (Photosynthesis= Carbon dioxide turns into Glucose)
- Animals feed on plants, passing the carbon compounds along the food chain. Most carbon they consume is exhaled as carbon dioxide during respiration. The animals and plants eventually die. (Respiration= Glucose turns into Carbon dioxide)
- Dead organisms are eaten by decomposers and carbon in their bodies is returned to the atmosphere as carbon dioxide. In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion. ( Combustion (burning)= Fuel (eg methane or wood) turns into Carbon dioxide)
20
Q
describe the process of the water cycle
A
- Evaporation- Water turns from a liquid to a gas when it evaporates. Energy from the Sun can evaporate water from all places on the Earth’s surface such as puddles, ponds, lakes and oceans.
- Condensation- After evaporation water can cool and convert from gas to liquid, often forming clouds.
- Transport- Water within clouds can be blown many miles by strong winds and so transported to other areas.
- Precipitation- Precipitation occurs when rain, snow, hail and sleet fall from the sky.
- Surface runoff- Much water will be absorbed into the ground after precipitation but if a large volume falls or the ground is already wet some water can run along the surface of the ground.
- Infiltration- This occurs when water that has fallen as precipitation is absorbed into the ground. This can then be stored within underground rocks called aquifers.
- Transpiration- Plants need to maintain a constant stream of water to their leaves for transport and support. So they allow some water to evaporate as water vapour from their leaves to mean that more is continually ‘pulled’ to their leaves from the soil.
21
Q
how does temperature affect the rate of decay of biological material?
A
- At colder temperatures decomposing organisms will be less active, thus the rate of decomposition remains low.
- (This is why we keep food in a fridge.)
- As the temperature increases, decomposers become more active and the rate increases.
- At extremely high temperatures decomposers will be killed and decomposition will stop.
22
Q
how does water affect the rate of decay of biological material?
A
- With little or no water there is less decomposition because decomposers cannot survive.
- As the volume of available water increases, the rate of decomposition also increases.
- Many decomposers secrete enzymes onto decaying matter and then absorb any dissolved molecules.
- Without water these reactions cannot occur.
23
Q
how does the availability of oxygen affect the rate of decay of biological material?
A
- Similar to water, decomposers need oxygen to survive and without it there is little or no decomposition.
- Oxygen is needed for many decomposers to respire, to enable them to grow and multiply.
- (This is why we often seal food in bags or cling film before putting it in the fridge.)
- As the volume of available oxygen increases, the rate of decomposition also increases.
- Some decomposers can survive without oxygen.
- (We use these in biogas generators.)
24
Q
one way how farmers and gardeners optimise the quality of their soil and why?
A
- by adding compost or manure.
- Compost is made from dead plants and manure is the waste from animals.
- Once spread on the soil, compost and manure are broken down into minerals by decomposing bacteria and fungi, as well as by other organisms, such as worms.
- Adding compost or manure helps recycle minerals so that they are absorbed by new plants and used in growth.
- Compost and manure also improve the quality of soil by increasing aeration and water retention.
25
Q
how can methane gas be produced from decaying materials for use as a fuel?
A
- Anaerobic decay produces methane and carbon dioxide.
- it occurs when bacteria and fungi break down dead matter without oxygen.
- This can happen naturally in some soils, particularly water logged soils, and in lakes and marshes.
- When people overwater their houseplants and flood the roots, anaerobic decay can occur, which can kill them.
26
Q
explain 3 ways environmental changes can affect the distribution of species in an ecosystem
A
- temperature- As you climb up a mountain the temperature reduces. This reduction, together with other
abiotic and biotic factors, determines what species of plant are found at different elevations. - water- All life on Earth needs water. Too much and some species will drown or rot. Too little and all species die.
- atmospheric gases- Gases dissolve in liquids, thus oxygen in the air dissolves in water. It is this dissolved oxygen, together with that produced by plants and algae, that support aquatic life. When levels of pollution increase the levels of dissolved oxygen reduce.
27
Q
explain what biodiversity is
A
- The range of animals and plants in a given area.
- the number of different species
- An area with large populations of few species is not biodiverse.
