Biology 2

Created by: a_nnmaria
Created on: 05-05-16 17:37

View mindmap

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

Get Revising

Biology 2

Comments

Similar Science resources: