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BIOLOGY B7 (The Carbon Cycle (1) CO2 is removed from the stmosphere by…
BIOLOGY B7
The Carbon Cycle
1) CO2 is removed from the stmosphere by green plants and algae during photosynthesis. The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins.
2) When the plants and algae respire, some carbon is returned to the atmosphere as CO2
3) When the plants and algae are eaten by animals, some carbon becomes part of the fats and proteins in their bodies. The carbon then moves through the food chain.
4) When the animals respire, some carbon is returned to the atmosphere as CO2
5) When plants, algae and animals die, other animals (called detritus feeders) and microorganisms feed on their remains. When these organisms respire, CO2 is returned to the atmospere
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8) So the carbon (and energy) is constantly being cycled - from the air through food chains and eventually back out into the air again
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Abiotic & Biotic Factors
Abiotic factors (non-living factors) - moisture level, light intensity, temperature, carbon dioxide level (for plants), wind intensity and direction, oxygen level (for aquatic animals), soil pH and mineral context
A change in the environment could be an increase or decrease in an abiotic factor e.g a change in temperature. These changes can affect the size of population in a community which will then affect the population sizes of other organisms that depend on them
EXAMPLE: a decrease of mineral content in te soil could cause nutrient deficiencies. This could affect plant growth in the population size.
Biotic factors (living factors) - new predators arriving, competition, new pathogens and availability of food
A change in the environment could be the introduction of a new biotic factor e.g a new predator or pathogen.
These changes can also affect the size of populations in a community, which could ave knock-on effects because of interdependence.
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Adaptions
Adaptations - the features and characteristics that allow organisms, and microorganisms, to adapt to live in different environmental conditions
1) STRUCTURAL - the features of an organisms body structure such as shape or colour,
EXAMPLE: arctic animals, like the arctic fox, have white fur so they're camouflaged against the snow to help them avoid predators and sneak upon prey
2) BEHAVIOURAL - the ways that organisms behave. EXAMPLE: many species, like swallows, migrate to warmer climates during the winter to avoid the problems of living in cold conditions.
3) FUNCTIONAL - things that go on the inside of an organisms body tat can be related to processes like reproduction and metabolism.
EXAMPLE: desert animals conserve water by producing very little sweat and small amounts of concentrated urine.
Extremophiles - organisms, like bacteria, that are adapted to live in extreme condition e.g in high temperatures, high salt concentrations or high pressures.
The Water Cycle
1) Energy from the Sun makes water evaporate from the land, sea and plants (transpiration), turning it into water vapour
2) The warm water vapour is carried upwards as warm air rises. When it gets higher up, it cools and condenses to form clouds.
3) Water falls from the clouds as precipitation (usually rain, but sometimes snow or hail) onto land where it provides fresh water for plants and animals, and some is absorbed by soil and is taken up by plant roots
4) Like plants, animals need water for chemical reactions that happen in their bodies. Animals return water to the soil and atmosphere through excretion e.g sweating, urination and breathing out
5) water that doesn't get absorbed by the soil will runoff into streams and rivers, then eventually drains back into the sea, before it evaporates all over again.
Using Quadrats
Where an organism is found is affected by environmental factors e.g in a field, daisies are more common in the open than under a tree because there is more light.
STUDYING THE DISTRIBUTION (where its found):
1) measure how common an organism is in two sample areas (using a quadrat) and compare.
2) study how the distribution changes across the area (by placing quadrants along a transect)
Quadrat - a square frame enclosing a known area to compare hoe common an organism is in two sample areas.
USING QUADRATS PRACTICAL:
1) place a quadrat on the ground at a random point within the first sample area.
2) count all the organisms within the quadrat
3) repeat steps 1 and 2 as many times as possible
4) work out the mean number of organisms per quadrat within the first sample area.
5) repeat steps 1 to 4 in the second sample area.
6)compare the two means
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Competition
Abiotic factors - non-living factors of the environment eg temperature
Biotic factors - living factors of the environment eg food
Ecosystem - the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
Organisms need things from their environment/other organisms to survive and reproduce:
1) plants need light, space, water and mineral ions from soil
2) animals need space, food, water and mates
Interdependence - when species depend on other species for food, shelter, pollination and seed dispersal. The interdependence of all the living things in an ecosystem means that any major change in the ecosystem can have far-reaching effects
Stable communities - when all the species and environmental factors are in balance that the population sizes are roughly constant. These include tropical rain forests and ancient wood oak lands
Global Warming
1) Gases in the atmosphere naturally act like an insulating layer. They absorb most of the energy that would normally be radiated back out to space and re-radiate it in all directions, which increases the temperature of the planet.
2) There are several different gases in the atmosphere which help keep the energy in called greenhouse gases. The main ones we worry about are carbon dioxide and methane because they are rising fast.
3) The earth is gradually heating up because of the increasing levels of greenhouse gases (global warming). It is a type of climate change and causes other types of climate change e.g changing rainfall patterns
CONSEQUENCES:
1)High temperatures cause sea water to expand and ice
to melt to rise.
2) The distribution of many wild animals and plant species may change due to the temperature increasing and the amount of rainfall changing.
3) Changes in migration patterns
4) Biodiversity could be reduced if some species are unable to survive a change in the climate, so become extinct.
Food Chains
Food chains always start wit the producer (they make their own food by energy from the sun). They are usually green plants of algae which make glucose by photosynthesis so some of it is used to make other biological molecules in the plant.
Biological molecules are the plants biomass.
Biomass- the mass of a living material. It is thought of energy stored in a plant, which is transferred through living organisms in an ecosystem when organisms eat other organisms.
Producers are eaten by primary consumers. Primary consumers are eaten by secondary consumers, Secondary consumers are eaten by tertiary consumers.
If the population of prey increases so does the population of predators, but as the population of predators increase, the population of prey decrease.
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Using Transects
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TRANSECTS PRACTICAL:
1) mark out a line in the area you want to study using a tape measure
2) the collect data along the line
3) you can do this by counting all the organisms you're interested in that touch the line
If its difficult to count all the individual organisms in a quadrant, like grass, you can calculate the percentage cover (percentage area) of the quadrat covered by a particular type of organism e.g by counting the number of little squares covered by the organisms
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