B3 Life on earth
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- Created by: revisionperson
- Created on: 05-01-13 22:29
Adaptation to the environment
A particular species is adapted to its environment,which helps it to survive,increasing its chances of reproducing. Cactus; leaves reduced to spines, thick outer layer for water loss.widespread rooting system.Fish-gills,streamlined shape,swim bladder
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Food chains
Shpow feeding releationships between different organisms. Enegy is passed up the food chain. Animals are dependant on each other for survival.
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Food webs
Show how all the food chains in a b=habitat are inter-releated, Can be complicated as animals have varied diets. Show how all living organisms are interdependant. Environmental changes can alter the food web.
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Energy transfer
All living things on earth, ultimately get their energy from the sun. Plants absorb a small amount of the suns energy during photosynthesis, when plants and animals are eaten or decomposed, decay organisms.
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Energy in food chains
At each stage, energy is lost through: heart or respiration, excreted as waste products, trapped in materials such as one and fur. less energy is available at each stage.
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Calculating energy effeciency:
Percentage of energy transferred=input energy/output energy x 100.
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The nitrogen cycle
-Animals and plants eat protein in other plants and animals.-Excess nitrogen is removed by excretion.-Plants and animals are decomposed by decay organisms.
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The nitrogen cycle continued...
Nitrates in the air are removed by nitrogen fixing bacteria. The nitrogen is then converted into compunds, e.g.nitrates. Plants take up these nitrates and converted to protein. Nitrates broken into nitrogen by bacteria-denitrification.
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The carbon cycle
-CO2 removed from the air by photosynthesis. -animals eat protein and use carbon in their cells.-plants and animals respire, releasing waste ad carbon dioxide into the air. Combustion of fossil fuels and forest fires.Decomposer organisms release CO2.
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Measuring environmental change
Use meters to measure levels of oxygen, carbon dioxide, nitrates and temperature. Using living organisms as indicators.
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Life on Earth
began 3500 million years ago. The first living things developed from simple living molecules that could copy or replicate themselves. It's not known wether the molecules were produced on conditions on Earth or arrived from an external source.
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The fossil record
-Supports common ancestor theory. Fossils can be fored by: 1.hard parts of organisms that don't decay easily. 2.Parts of animals or plants that haven't decayed as a condition needed was absent. Soft parts of organisms that can be replaced by minerals
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DNA Evidence
Analysis of living organisms show similarities and differences.-Can fill gaps in fossil record. Comparing gene sequence reveals that the DNA of some organisms is similar even when they look different.
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Evolution by natural selection
1.Individuals show variation. 2.Competition for food and mates, disease and predators. 3. better adapted are more likely to survive. 4.Survivors pass on the genes to offspring.
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Selective breeding
Animals with certian traits are bred to produce offspring with certain desirable characteristics. Selective breeding=human purposes. Natural selection=suit envornment
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Packing and sustainability
-Too much packaging is used. -Household schemes and biodegradable resources. Cardboard instead of polystrene, carrier bags from cellulose.
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Other cards in this set
Card 2
Front
Shpow feeding releationships between different organisms. Enegy is passed up the food chain. Animals are dependant on each other for survival.
Back
Food chains
Card 3
Front
Show how all the food chains in a b=habitat are inter-releated, Can be complicated as animals have varied diets. Show how all living organisms are interdependant. Environmental changes can alter the food web.
Back
Card 4
Front
All living things on earth, ultimately get their energy from the sun. Plants absorb a small amount of the suns energy during photosynthesis, when plants and animals are eaten or decomposed, decay organisms.
Back
Card 5
Front
At each stage, energy is lost through: heart or respiration, excreted as waste products, trapped in materials such as one and fur. less energy is available at each stage.
Back
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