Biology 2

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  • Created on: 05-05-16 17:37
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  • Biology 2
    • Classification
      • Classification is important because it can show how closely species are related - an evolutionary relationship. It is also important because it can show an ecological relationship too. Classification is important for conservation.
        • Evolutionary tree shows how closely related different species are.
          • Evolutionary trees show common ancestors and relationships between species.
      • Species
        • Species is a group of living organisms which can interbreed to produce fertile offspring.
        • Problems
          • Asexual reproduction- An organism makes a copy of itself-there is no interbreeding so it doesn't fit the species.
          • Hybirds - if you interbreed a male a with a female , but usually infertile.
          • Evolution- Organisms change and evolve over time, so the way that they have been classified might change.
        • In the bionomal system every species has a two part latin name. The first part refers to the genus and second to the species.
      • Kingdoms
        • Protists (Protocista)
          • Mostly muliticellular; cells have a nucleus.
        • Fungi
          • Multicellular, sapophytic feeders; have cell walls;cells have a nucleus.
        • Plants (Plantae)
          • Miulticellular, autotrophic feeders so have chloroplasts; have cell walls made of cellulose; cells have a nucleus.
        • Animals (Animalia)
          • Multicelluar; Hetrotropic feeders; no cell walls;cells have a nucleus.
          • They are divided into kingdoms: Phylum, class, order, family, genus and species.
    • Energy Transfer& Flow - Pyramid of biomass and numbers
      • Biomass is the dried mass of an organism.
        • Biomass pyramids are almost pyramid shaped because biomass is lost at each stage in a food chain.
          • To construct a pyramid of biomass you use the dry biomass of organism and it can be hard to produce accurate pyramid of biomass because some feed at more than one tropic level.
        • Pyramid of numbers shows the number of organisms at each stage in food chain. These are usually other shapes.
      • Energy Flow
        • 1) Energy from the sun is the source for nearly all life on earth.
        • 2) Plants use a small percentage of light energy from the sun to make food during photosynthesis. His energy then worked its way through the food chain as animals eat plants and each other.
        • 3) The energy lost at each stage is used for staying alive, i.e. in respiration which powers all life processes.
        • 4) Most energy is eventually lost into its surroudings as heat. This is espicially true for mammels and birds, whose bodies need to main a constant temperature.
        • 5) Materials and energy are also lost from the food chain as waste products. This happens through the process of excretion.
        • 6) Waste products and uneaten parts can become starting points for other food chains.
        • Material and energy are both lost at each stage of the food chain. Most of the biomass is lost and explains why food chains cant go higher than 5 tropic levels.
        • Efficiency= energy available next level/ previous level energy x100
      • Food chain
        • Producer, Primary consumers, Secondary Consumers
    • Interactions between organisms
      • Organisms compete to survive,
        • Inter specific Competition.
          • Where organisms compete for resources against individuals of another species.
            • Intraspecific competition often has a bigger impact because same species have exactly the same needs, so they'll compete for lots of resources.
        • Intraspecific Competition
          • Where organisms compete for resources against individuals of the same species.
            • Intraspecific competition often has a bigger impact because same species have exactly the same needs, so they'll compete for lots of resources.
      • Predator - Prey relationship
        • 1) The population of any species is usually limited by the food available.
        • 2) If the population of prey increases, then so will the population of predators.
        • 3) However, as the population of predators increase, the number of prey will decrease.
        • 4) Predator-prey cycles are usually out of phase as it takes a while to respond to changes in other population.
        • Parasites live off a host. They take what they need to survive. E.g. Tapeworm
        • Mutualism is a relationship where both organisms benefit. E.g. Oxpeckers
    • Adaptations
      • Adaptations are features that organisms have that make them better suited to their environment.
      • Specialists are organisms which are highly-adapted to survive in a specific habitat.
        • E.g. Giant pandas are highly adapted to eat just bamboo
      • Generalists are organisms that are adapted to survive in a range of different habitats,
        • E.g. black rats are able to survive in forests, cities and farmland.
      • Counter Current exchange system
        • 1) Animals like penguins have to stand on cold ice all day.
          • 2) Blood vessels going to and from the feet carry blood that flows in opposite direction.
            • 3) The vessels pass close to each other, allowing heat to transfer between them.
              • 4) Warm blood flowing in the arteries to the feet heats cold blood returning to the heart in veins.
                • This means that the feet stay cold, but it stops cold blood from cooling down the rest of the body.
      • Cold environments
        • Behavioural
          • 1) Many species migrate to warmer climates during the winter months to avoid cold conditions.
          • 2) Other species hibernate during the winter months. This saves energy.
          • 3) Some species huddle together to keep warm.
        • Anatomical
          • Have a thick coat to insulate the body and trap heat.
          • 2) Have a large compact body shape to give smaller surface area to volume ratio.
          • Counter Current exchange system
            • 1) Animals like penguins have to stand on cold ice all day.
              • 2) Blood vessels going to and from the feet carry blood that flows in opposite direction.
                • 3) The vessels pass close to each other, allowing heat to transfer between them.
                  • 4) Warm blood flowing in the arteries to the feet heats cold blood returning to the heart in veins.
                    • This means that the feet stay cold, but it stops cold blood from cooling down the rest of the body.
      • Hot Environment
        • Anatomical
          • 1) Animals that have adapted to hot places are small because large surface area to volume ratio lose heat.
          • 2) Having large ears can also increase an animals SA to Volume ratio. Large thin ears allow more blood to flow near the surface of the skin.
          • 3) Some animals store fat in one part of their body. This stops the rest of the body from being too insulated and allow heat to be lost.
        • Behavioural
          • 1) Animals that live in very hot climates often spend the day in the shade or underground to minimize the amount of heat.
          • 2) Animals can also reduce their heat gain by being active at night.
          • 3) Animals can increase heat loss by bathing in water. As the water evaporates it transfers heat from the skin.
        • Desert
          • Animal
            • 1) have specialised kidneys that produce concentrated urine.
              • 2) have no sweat glands preventing them from losing water.
                • 3) Spend time in underground burrows where the air conditions are moisture.
          • Plant
            • 1) have a rounded shape to minimize water loss.
              • 2) have a thick waxy layer to prevent water loss
                • 3) store water in their stems to survive in times of extreme drought.
    • Evolution
      • Darwin
        • Theory of Natural selection
          • 1) Darwin knew that organisms in species show wide variation. He also knew that organisms have to compete for resources.
          • 2) Darwin concluded that the organisms are best adapted would be more successful competitors.
          • 3) The successful organisms are likely to reproduce and pass on their adaptation.
          • 4) The organisms that are less well adapted would be less likely to survive and reproduce.
          • 5) Overtime, successful adaptations become more common in the population and they species change.
        • Not believe Darwin's theory for 3 reasons:
          • 1) Went against religious beliefs how how life on earth formed.
          • 2) Couldn't explain why new, useful characteristics appeared.
          • 3) There wasn't enough evidence to convince other scientists.
        • Now they accept:
          • The theory had been debated and tested independently by scientists.
          • Offers a plausible explanation for so many observations.
      • Lamarck
        • Lamarck argued that if the characteristic was used a lot by an animal then it would become more developed He reckoned acquired characteristics could be passed onto the animals offspring.
        • However, people eventually concluded that acquired characteristics do not have a genetic basis- so they can't be passed on.
    • Human Impact on the environment
      • Human population increases when the birth rate is higher than the death rate. This puts pressure on the environment.
      • Increasing amounts of pollution are causing...
        • Global warming
          • Fossil fuels are coal, oil and gas.
          • When they're burned, they release carbon dioxide which is greenhouse gas. Global temperature  until  when trapped heat and this causes global warming.
          • Scientists have predicted that if global temperatures continue to go up, sea levels will rise and weather systems will become unpredictable.
        • Acid Rain
          • 1) When fossil fuels and waste are burnt release gas called sulfur dioxide.
          • 2) Sulfur dioxide reacts with water in the atmosphere to form sulfuric acid which falls as acid rain.
          • 3) Acid rain damages soils and kills trees.
          • 4) Acid rain causes lakes to become more acidic. This has effect on the ecosystem.
          • 5) Acid rain damages limestone, ruining buildings and stone statues.
      • Ozone Depletion
        • CFC's used to be used for aerosols, fridges, air-conditioning units.
        • They break down ozone in the upper atmosphere.
        • This allows more harmful UV rays to reach the Earth's surface.
        • Being exposed to more UV rays increases the risk of skin cancer. Australia has high levels of skin cancer because it is under ozone hole.
        • The increase in the UV rays might also kill plankton in the sea-this could have a massive effect on the sea ecosystem.
      • Indicator species can be used to show pollution.
        • Some species can only survive in unpolluted conditions, so if you find lots of them, you know its a clean area.
          • Lichens are used to monitor air quality.
            • Mayfly larvae monitor water quality.
        • Other species have adapted to live in polluted conditions, so if you see a lot, then you know there's a problem.
          • Water lice indicate water pollution.
        • Ways of measuring pollution
          • See if  species is present or absent from an area.
          • Count the number of indicator species in an area allowing measurements from different areas.
          • Sensitive instruments can measure the concentrations of chemical pollutants.
          • Satellite data to indicate pollutant level.
      • Advantages and Disadvantages  with measuring methods.
        • Living Methods
          • Advantages - Using living methods is relatively quick, cheap and easy way of saying whether an area is polluted.
          • Disadvantages- Factors other than pollution can influence the survival of indicator species so living methods are not reliable.
        • Non-living methods
          • Advantages- Directly measuring the pollutants gives reliable, numerical data thats easy to compare.
          • Disadvantages- Non living methods often require more expensive equipment and trained workers than methods using indicator species.
    • Sustainable Developement
      • Sustainable development means providing for the needs of the increasing population without harming the environment.
      • As the human population gets bigger...
        • we need to produce more food-so we'll need to continue farming.
        • We use up more energy. At the moment the vast majority of energy come from burning fossil fuels.
        • We're producing more waste-it all needs to be disposed and at the moment it's polluting the earth.
      • Examples
        • Fishing quotas have been introduced to prevent some types of fish to be come extinct.
        • To make production of wood and paper sustainable there are laws insisting logging companies.
      • Education is important. I people are aware of a problem they are more likely to help. Sustainable development helps endangered species by considering the impacts on their habitats.
      • Conservation programme benefit wildlife &humans
        • Protecting human food supply
          • Over fishing has greatly reduced fish stocks in the oceans. Ensure future generation have fish to eat.
        • Ensuring minimal damage to food chains
          • If one species becomes extinct it will affect the organisms that feed on and are eaten by that species so the whole food chain will be affected.
        • Cultural Aspects
          • Individual species may be important in a nations or an areas heritage.
        • Providing future medicines
          • Many of the medicines we use today come from plants. Undiscovered plant species may contain new medicine chemicals.
        • Conservation programme are designed to help save endangered plants and animals. They involve things like protecting habitats and captive breeding.
        • Evaluation
          • Genetic Variation
            • Genetic variation to survive the appearance of new diseases.
          • Viability of populations
            • They should be able to reproduce.
          • Available habitats
            • plenty suitable habitats to live in.
          • Interaction between species
            • they interact as they would in natural environment

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