Biology Unit 1.b

Biology Unit 1.b

1. Adaptations

   • Artic Animals
     • Well Insulated
       • Blubber for insulation
         • Also energy source
       • Hairy coats/greasy fur
         • Keeps body heat in
         • prevents cooling
     • Camo
       • White fur - avoid predators/catch prey
     • Small Surface area compared to Volume
       • Less surface area - less heat loss
   • Desert Animals
     • Large Surface Area compared to Volume
       • Lose more body heat - don't overheat
     • Efficieny with Water
       • Small amounts of concentrated urine
     • Camo
       • Sandy Colour - avoid predators, catch prey
     • Hot conditions
       • Thin layer of body fat
       • Thin coat
       • Lose body heat
       • Camels have humps for fat
   • Desert Plants
     • Water Storage Tissues
       • water in thick stem
     • Water Absorption
       • shallow/extensive roots
     • Small surface area compared to volume
       • Spines instead of leaves so reduce water loss

2. Competition and Environmental Change

   • Plants compete
     • Light
     • Space
     • Water
     • Nutrients
   • Animals compete
     • Territory
     • Food
     • Water
     • Mates
   • Effect on Population
     • Increases
       • More prey
         • Predators survive and reproduce
     • Decreases
       • Less food
       • Disease
     • Distribution Changes
       • Temp change
   • Living Factors
     • Change in Infectious Disease
     • No. Predators
     • Food sources
     • Competitors
   • Non Living Factors
     • Change in temp
       • Satellites
       • Weather Stations
     • Change in rainfall
       • Rain Gauges
     • Change in water/air pollution
       • Dissolved Oxygen Meters
         • Concentration of dissolved oxygen in water
       • Number of Lichen
       • Less oxygen - more bacteria
       • Adapted eg; sludgeworms

3. Energy Transfer

   • Carbon Cycle
     • Plants photosynthesize, removing CO2 from atmosphere
     • Some carbon returned to atmosphere in respiration
     • Detritus Feeders/microogranisms feed on the dead and respire
     • Detritus Feeders/microorganisms feed on waste
       • Compounds in waste taken up by soil as nutrients and put back in food chain
     • Combustion releases CO2
   • Pyramids of Biomass
     • Less energy/biomass moving up a stage/trophic level
     • Biomass is the mass of living material
     • Bottom bar is the producer
       • Primary Consumer
         • Secondary Consumer
   • Energy Transfer and Decay
     • Sun is source of energy for nearly all life
     • Material and energy lost at each stage of the food chain
       • Heat
       • Movement
       • Waste material/excrement
     • Decay
       • Waste materials decayed by microorganisms
         • Microorganisms work best in warm, moist conditions
           • Compost bins
         • Elements put back in soil

4. Genes/Chromosomes/DNA

   • Nucleus contains chromosomes
     • 23 pairs of chromosomes
   • Chromosomes carry genes
   • DNA carries genetic code
   • DNA is coiled to form arms of chromsome

5. Variation

   • Environment
     • Difference caused by living conditions
     • Eg; plant grows green in sun but yellow in darkness
   • Genes
     • Characteristics determined by inherited genes
     • Pass on in Gametes
     • Combining of genes causes variation
     • Alleles
       • Different versions of same gene
   • Most characteristics determined by a mixture

6. Reproduction/Cloning/Genetic Engineering

   • Reproduction
     • Sexual
       • Fusion of male and female gametes
       • Offspring contain mixture of parents genes
         • Variation
         • Each gamete has 23 chromosomes
       • Genetically different
     • Asexual
       • Genetically Identical
       • X Chromosomes split down middle
         • 2 sets of DNA strands
           • Membrane forms round each set
             • DNA replicates itself - 2 identical cells with complete x chromosomes
       • 1 parent
   • Genetic Engineering
     • Gene cut from Chromosome
       • Using enzymes
       • Insert gene into chromosome
     • GM Crops
       • Resistance
         • Viruses, insects, herbicides
       • Pros
         • Increase yield
         • Provide Nutrients
         • Currently grown without problems
       • Cons
         • Reduce Biodiversity
         • Not safe - allergies
         • Herbicide resistance
     • Sheep
       • Milk treats human diseases
     • Genetic Disorders
       • insert working genes into sufferers
   • Cloning
     • Cuttings
       • Cuttings taken from good plants
         • Plant them to produce clones
       • Quick and Cheap
     • Tissue Culture
       • Plant cells put in growth medium with hormones
         • Grow into new plants
       • Quick, little space needed, grown all year
     • Embryo Transplants
       • Sperm and Egg cells taken
         • Egg is artificially fertilised
           • Embryo develops and splits to form clones
             • Cloned embryos implanted
       • Hundreds made a year
     • Pros/Cons
       • Reduced gene pool - fewer alleles
         • may not be allele to give resistance to disease
       • Clones not as healthy
         • Arthritis
       • Unsuccesful human attempts
       • Greater Understanding
       • Preserve Endangered Species
     • Adult Cell
       • Removing genetic material from unfertilised egg cell
         • Complete set of chromosomes from and adult body cells inserted in empty egg cell
           • Stimulated by electric shock
             • Divides, like normal embryo
             • Implanted into adult female
               • Clone of original adult body cell

7. Evolution

   • Natural Selection
     • Mutations occur in DNA
       • Better adapted to survive
         • Breed
           • Pass on mutated allele/gene
             • Eventually whole pop has mutated gene
     • Arguments against
       • Went against religioun
         • God created everything
       • Lack of evidence
       • Genes and variation hadn't been discovered yet
         • Darwin couldn't explain why
   • Lamarck
     • The more an organism used a feature, the more it would develop in it's lifetime
       • Improved characteristic would pass on
       • EG; If a rabbit ran a lot, it would grow longer legs
   • All organisms are related