721998
Description
Flashcards by blueaweiss, updated more than 1 year ago
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Created by blueaweiss
over 10 years ago
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| Question | Answer |
| What are species? | Organisms that can breed together to form fertile offspring |
| Define habitat | the environment where an organism lives |
| What could cause competition? get 3 to be positive | breeding sites, food, mates, living space, territories |
| Define interdependence | When organisms depend on each other for survival |
| How does energy get lost in the food chain? (3) | 1) Heat- as organisms respire 2) waste products from excretion 3) Uneaten parts of animals |
| What is the equation for the percentage efficiency of energy transfer in a food chain? | percentage efficiency= (energy in tissues / energy in food eaten) X 100 |
| What is the final energy transfer in a food chain? | Dead and decaying matter being feed on by decomposers |
| Name 2 decomposers, how do they work and why are they important | 1) Fungi and bacteria 2)release enzymes to break down organic matter before they digest it 3) Play an important role in recycling the nutrients in an ecosystem |
| Explain the 5 stages of the carbon cycle | 1) carbon dioxide enters atmosphere by combustion, 2)taken in by trees and green plants in photsynthesis (they fix carbon from co2 to their cells) 3) plant eaten by animals or decompose releasing c02 4) Animals release co2 in respiration 5) animals then die and when funigi and bacteria decompose them carbon released. |
| What are the 5 stages of the nitrogen cycle? (in terms of nitrogen compounds) | 1) plants absorb nitrates from the soil through their roots which they use to make proteins 2) animals feed on proteins 3) animals excrete waste 4) animals and plants decay and nitrogen retunes to the 5) Nitrates are returned to the soil |
| How does nitrogen in the air get to the soil and become useable to plants? | Nitrogen fixing bacteria found on the nodules of legumes and in the soil convert nitrogen gas in the air to nitrates |
| How do nitrates get back into the atmosphere? | In waterlogged conditions denitrifying bacteria convert nitrates in the soil back to nitrogen gas |
| What are non living indicators of environmental change? (2) | carbon dioxide levels, temperature. levels of nitrates in the water etc |
| What are living indicators of environmental change? | living populations of organisms that signal conditions of an environment like plankton, lichens or mayflies |
| What do phytoplankton indicate? in terms of living indicators | Are at the start of the aquatic food chains so effects on their numbers will effect the whole ecosystem |
| What do mayflies indicate? | Mayflies need a high level of oxygen and little pollution to survive so populations of them indicate the water conditions |
| What do lichens indicate? | Air quality can be measured by observing the communities of lichens that are able to grow |
| What are fossils and why are they useful? | Dead bodies of plants and animals buried and turned to rock, impotent as they give information about how organisms changed and evolved over time |
| Why has evolution come about? | Variation |
| What is a mutation? | a random change in the genetic information of a cell - can cause variation |
| What is the theory of evolution? | Organisms had mutations those with successful mutations were better adapted so reproduced and their genes went in gene pool. Evolution is the change in frequency of genes in long periods of time. |
| What is the theory of natural selection? | If organisms have beneficial variation then they will survive and pass on their traits to their offspring if organisms are not they will die off- thus the best organisms survive |
| What is selective breeding? How is it done And give an example | Breeding animals to exaggerate certain characteristics, it is done by choosing and breeding 2 animals closest to a particular desired trait whose offspring will be closer to the desired trait than the previous generation. This is then repeated and repeated. An example is with cows that have been bread to make more milk or have more meat |
| Explain the melanic moth example of natural selection? | The moths were originally light when there was a lot of pollution and smog the trees got darker and so the light moths were spotted easier by predators. When one developed the peppered trait it was better adapted and survived better than the white moths then population was mainly peppered when pollution decreases this reversed |
| What happens if an organism is isolated | It is likely to develop different genes to others of its species as different genes are beneficial may eventually lead to new species evolving |
| Explain the tree of life | Shows the relationship between all organisms, organisms on the same branch being genetically close to those further away, shows we all started from the same thing. |
| What did Darwin find? | On the galapagos islands he found that same species e.g. mockingbirds had different adaptations accroding to suroundings. He propposed natural selection. |
| What did Lamarck propose | animals developed traits over lifetime and passed them on. |
| What does biodiversity mean? | Variety of organisms living in an ecosystem |
| Why do we classify animals and what happens as you go down the classification list? | In order to record and monitor species across the globe accurately and universally n As you go down the list the organisms are more similar e.g at beginning its kingdom at the end its species |
| What do we mean by sustainability? | Meeting the demands of today without compromising the demands of the future |
| Why is it important to maintain ecosystems in terms of the otter example? | When otters were hunted it meant the number of sea urchins increased as otters feed on these. This meant the sea beds where fish lay eggs were destroyed thus fish stocks began to decline |
| What is intensive crop production? And what are issues with this | Involves the large scale planting of one crop - called mono culture bad because has a very negative effect on biodiversity |
| How could we improve biodiversity on farmland? (2) | Replant hedges between fields so diveristy can occur there. Create beetle banks for beetles that eat aphids (that would otherwise damage the crop) to live on. This can have financial benifits as farmers need less pesticides as wildlife feeds on hedges and beetles kill pests |
| How do we improve sustainability of products ? (3) | minimal packaging, re- using of packaging, produced with little energy, using local products to produce product (less transport footprint) |
| What is the lifecycle assessment? | tracks a products environmental impact from manufacture, transportation to distribution centres ,to usage to disposal |
| Why is biodegradable packaging good? but what is better | Means less rubbish in land fill, but releases carbon dioxide when degrades and energy in production using little or no packaging is better |
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