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31 Cards in this Set
- Front
- Back
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all organisms are classified into a number of groups, what are these groups?
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kingdom, phylum, class, order, family, genus and species
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what has enabled scientists to know much more about how closely animals are related?
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sequencing the bases in DNA, it has meant that often organisms can be reclassified
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what is a 'species'?
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a group of organisms that can interbreed to produce FERTILE offspring
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how does the binomial naming system work?
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there are two parts to the name, the first is the genus the second the species
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it is sometimes difficult to classify certain animals, give a named example and why it is hard to classify?
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ARCHAEOPTERYX - it had feathers like a bird, it also had teeth and a long, bony tail, like a reptile
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what are mules and why cant they be classed as a species?
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mules are hybrids produced when members of two species (eg horse and donkey) interbreed, they are infertile so they cannot be classed as a species
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why is it hard to classify bacteria?
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they reproduce asexually, so they cant be classified using the 'fertile offspring' idea
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what can both pyramids of number and pyramids of biomass be used to represent?
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feeding relationships between organisms in a food chain or web
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what do pyramids of biomass show?
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the dry mass of living material at each stage of a food chain
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why do pyramids of number & biomass sometimes look different?
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if producers are very large, a small parasite lives on a large animal
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why are pyramids of biomass hard to construct?
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some organisms feed on others from different trophic levels, measuring dry mass if difficult as you have to drain all the water from the animal, killing it.
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how is energy lost in a food chain apart from growth?
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respiration, egestion, excretion
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how is carbon released into and absorbed from the air?
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released by plants and animals respiring, soil bacteria acting as decomposers, burning of fossil fuels
absorbed by oceans |
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what does an ecological niche describe?
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the habitat that an organism lives in and its role in that habitat.
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what is interspecific and intraspecific competition?
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interspecific is between organisms of different species, intraspecific is between organisms of the same species
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why do both predator and prey show cyclical changes in their numbers?
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when there are lots of prey, more predators survive and so their numbers increase, the increased number of predators eat more prey so prey numbers drop meaning more predators starve and so their numbers drop and the cycle starts again
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what is mutualism and give an example of this
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when both organisms benefit as a result of their relationship. insects visit flowers and allow pollination to happen and they are rewarded with the sugary nectar.
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what are specialists and generalists give an example of each
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some organisms are very well adapted to living in specific habitats and would struggle to live anywhere else (polar bears)
others are able to live in several habitats (rats) |
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summarise the modern version of charles darwins natural selection theory
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with in any species there is variation, organisms produce more young than will survive so there is competition for limited resources, only those best adapted will survive, those that survive pass on their successful adaptations to the next generation. over time the changes produced may result in a new species
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why is natural selection hard to study?
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because it happens over thousands of years
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why didnt people agree with darwins theory and why do they now?
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at first people thought he did not have enough evidence, many people thought god had created all species.
now it explains lots of observations and it has been tested by many different scientists |
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what was jean baptiste de lamarks incorrect theory about how characteristics were passed on?
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it was called the law of acquired characteristics, for example giraffes acquired long necks for feeding and this characteristic was then passed on.
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there are many types of pollution but what are three main ones that people are concerned by?
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carbon dioxide (which may increase greenhouse effect and global warming)
CFC's which destroy the ozone layer sulfur dioxide which causes acid rain |
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what is it called when something grows at an ever increasing rate?
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exponential growth
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what does a persons 'carbon footprint' measure?
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the total greenhouse gas given off by a person or organisation within a certain time
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the presence or absence of indicator species is used to estimate levels of pollution, name 5 of these and what they show.
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mayfly larva is an insect that only lives in clean water
the waterlouse, bloodworm and mussels can live in polluted water. lichen grows on trees and rocks but only when the air is clean |
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what are direct methods of measuring pollution?
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oxygen probes can show how much oxygen is in a pond, special chemicals can indicate levels of nitrate pollution from fertilisers
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what are the advantages to the different methods of measuring pollution?
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indicator organisms are cheaper, no equipment that could go wrong
using direct methods can give more accurate results and any given time |
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why do people think conservation is important?
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protects our food supply, prevents damage to food chains, protects plants and animals that might be useful for medicine uses, protects habitats and organisms people like to visit and study
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whales have been hunted fro many years for what?
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skin is used in belts, shoes and bags
teeth used in buttons, piano keys and jewellery liver used in oil whale meat used for pet and human food bone used it fertiliser and animal feed |
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why do some scientists think they need to kill some whales?
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to find out more about how whales can survive at extreme depths, however some things eg communication and migration can only be studied if the whale is alive
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