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| Question | Answer |
| What is a species? | A group of organisms that can breed together to produce fertile offspring |
| What can adaptations do? | Increase an organisms chances of survival and successfully reproducing |
| What is the interdependence of living things? | How the loss of one organism has an effect on other organisms in a food web |
| What could happen to organisms poorly adapted to their environment? | Less likely to survive and reproduce, so could lead to extinction |
| What can make a species go extinct? | - rapid changes in the environment e.g. climate - new diseases - new predators - new competitors |
| How can humans be responsible for extinction of certain species? | Direct activity of humans e.g. shooting the animal, or indirect activity of humans e.g. placing competitors in the same habitat as the species |
| Plants absorb a _____ percentage of the Sun's energy for photosynthesis | small |
| How can energy be transferred in the ecosystem? | Animals eating |
| In a food chain, what percentage of energy is passed onto the next trophic level? | 10% |
| In a food chin, where does most of the energy go? | - passed out via heat - used for life processes e.g. movement - parts of dead organism feed on and broken down by decomposers - can be excreted and passed on to decomposers |
| What happens as less energy is transferred at each trophic level? | As you go up a trophic level, the number of organisms at each level gets smaller |
| How do all cells contain carbon? | They all contain proteins, fats and carbohydrates |
| How can carbon dioxide be removed from the atmosphere? | Photosynthesis by green plants, which uses the carbon to become part of more complex molecules like proteins, fats and carbohydrates in plants |
| How can carbon dioxide be returned to the atmosphere? | Respiration by plants, animals and microorganisms |
| How can carbon be passed from one organism to the next? | Through eating - when an animal eats a plant, carbon from the plant becomes part of the fats and proteins in the animal. Also, some animals and microorganisms feed on waste materials and dead animals which passes carbon onto these microorganisms and detritus feeders (dead matter) |
| Why do materials from living things decay? | They are digested by microorganisms, which ca be digested quicker in warm, moist conditions with lots of oxygen |
| Why do plants and animals need nitrogen? | To make proteins |
| Why can't nitrogen from the air be used by plants and animals? | It isn't reactive enough |
| What is nitrogen fixation? | Making nitrogen compounds from nitrogen in the air |
| How can lightning cause nitrogen fixation? | It splits nitrogen molecules into nitrogen atoms which react with oxygen to form nitrogen oxides. They are then washed to the ground by rain, where they form nitrates in the soil |
| What do nitrogen-fixing bacteria do? | Found in soil and some plants, and fix nitrogen gas into nitrogen compounds |
| What is the Haber process? | Nitrogen and hydrogen react to form ammonia, which is used by farmers as a fertiliser to produce nitrogen compounds in plants |
| How can nitrogen compounds be returned to the soil? | - excretion by animals - decay of dead plants and animals |
| What does denitrifying bacteria do? | Present in soil, and breaks down nitrogen compounds and releases nitrogen gas into the air |
| When did the first living things exist? | 3.5 billion years ago |
| What is the main theory for life on Earth beginning? | Replicating molecules, that were either produced by the conditions of Earth millions of years ago, or came from somewhere else (e.g. another planet) |
| What happens with replicating molecules? | Overtime, they begin to join together and become more complex and dependent on each other. The process of natural selection has led to different species |
| Who was Charles Darwin and what was his theory of evolution? | An English nationalist, who studied variations in plants and animals. His theory was that all different species have evolved from simple life forms |
| Darwin's theory of evolution occurs through natural selection, what is it? | In a species, individuals show a wide variation with different characteristics. Those with characteristics more suited to their environment are more likely to survive and reproduce, and these successful genes are passed onto offspring |
| What happens if an individual is poorly adapted to its environment? | Less likely to survive and reproduce, so genes are less likely to be passed onto offspring. These die out, and gradually overtime a species will evolve |
| What type of variation allows the change to pass onto the offspring? | Genetic variation |
| What would happen if conditions on Earth in the past were different? | Natural selection would have different results as our bodies would change to suit Earth's conditions |
| What is selective breeding? | Changes in an animal or plant due to human intervention. We choose what characteristics we want and breed a male and female with these characteristics. The offspring who show these characteristic the most are then bred, and this carries on over many generations |
| What are mutations? | Changes that can occur in genes randomly, can be caused by background radiations and chemicals e.g. cigarette smoke. The changes can sometimes be severe and make cells die or cancerous, and have such little effect the cell survives. In rare cases, the changes may be beneficial and produce new and useful characteristics |
| Why does it matter in which cells mutations occur? | If the mutations occur in normal body cells, they lost when we die. But if they occur in sex cells, the changes can be passed onto offspring |
| How can we determine if a new species has been created? | It cannot breed with the original species, but it can still have fertile offspring |
| Why do some people not agree with the theory of natural selection? | They think it is too complex for organisms so complex to be created through natural selection. Also, and religious believers think God created all living things |
| Who was Jean-Baptiste Lamark and what was his theory? | A French scientist, and he thought that if a characteristic was used more, it would become bigger and stronger (giraffes neck) , whilst characteristics that weren't used as often would eventually disappear |
| Why can't Jean-Baptiste Lamark's theory account for all observations on Earth? | If his theory was true, all organisms would become complex, and all simple organisms would disappear. Darwin's theory can account for the continued presence of simple organisms |
| Why can scientists find it hard to accept new theories? | They devote their life to their research, and therefore find it hard to accept their theory is wrong |
| What evidence is there for Darwin's theory? | Most comes from fossils, that show how organisms have changed overtime, but there are gaps as not all fossils have been found and some have been crushed by the Earth's movement. Also, his theory fits in with the understanding of genetics and mutations in bacteria |
| What is biodiversity? | The wide range of life on Earth |
| What characteristics can the classification or organisms be determined by? | - physical features - DNA |
| How can classification help scientists? | Help them make sense of the diversity on Earth and show evolutionary relationships between organisms |
| Why is maintaining biodiversity important? | We have begun to realise w idea range of species can be used to obtain potential crops and medicines available for future generations. |
| What is monoculture? | The continuous production of one crop so it can be harvested more easily as they grow at the same rate |
| What are the disadvantages of monoculture? | Farmers can use chemical pesticides which can make a species go extinct, reducing biodiversity |
| Why isn't it preferred to use biodegradable materials for packaging? | If there isn't enough oxygen in the landfill, the greenhouse gas methane can be produced contributing to global warming |
| What factors are there in reducing sustainability? | Materials and energy used in production, transport and also the amount of pollution created |
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