Topic 5

• Adaptive radiation


  the diversification of several new species from a recent ancestral source

  eg. pentadactyl limb, darwin's finches
• Artificial selection


  the human intervention in animal or plant reproduction to ensure that certain desirable traits are represented in successive generations.
• Continuous variation


  the variation in phenotypic traits in species.

  a series of types are distributed on a continuum rather than discrete categories.
• Discontinuous variation


  the variation in phenotypic traits in which types are grouped into discrete categories with few or no intermediate phenotypes.
• Evolution


  the cumulative change in the inheritable characteristics of a population.

  a result of natural selection acting on genetic variation.
• Fossil


  a preserved remains or representation of an organism that existed in a past geological age.

  minerals seep into the tissue and harden over time.

  shows evolution and common ansestors.

  eg. mineralized bones, shells, etc., as casts, impressions, and moulds.
• Divergent evolution


  the change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species.
• Heritable characteristics


  characteristics that are capable of being passed from one generation to the next through the genes.
• Homologous structures


  anatomical structures derived from a common ancestor, but evolved to serve different purposes.

  Recent common ancestor.

  eg. pentadacty limb - wing, hand, and hoof.
• Melanism


  an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an organism, resulting from the presence of melanin.

  eg. industrial revolution moths.
• Pentadactyl limb


  a limb with five digits

  eg. human hand or foot,

  in many amphibia, reptiles, birds, and animals,

  --> all these species derived from common ancestor.
• Population


  a group of organisms of one species that interbreed and live in the same place at the same time
• Selective breeding


  the intentional breeding of organisms with desirable traits in an attempt to produce offspring with similar desirable characteristics or with improved traits.
• Species


  same characteristics and capable of mating to produce fertile offspring.
• Adaptations


  a feature of an organism that favours its survival to reproductive age.

  can be behavioural, physiological, or structural.
• Antibiotic


  a chemical produced by microbes to kill off competing microbes.
• Antibiotic Resistance


  - Usually antibiotics kill all invading cells

  - Sometimes a few are resistant

  --> survive and reproduce, out-competing the non-resistant

  - Pass on inheritable traits that make them resistant

  - Becomes difficult to treat --> new antibiotics/stronger

  - Superbugs such as MRSA in hospitals are very resistant to lots of types, so very dangerous.
• Meiosis


  reduction division involving the production of gametes.
• Mutation


  a change in DNA.
• Natural selection


  The mechanism of evolution in which various genetic types make different contributions to further generations.

  - Populations are generally stable despite large number of offspring.

  - Better adapted individuals have a competitive advantage.

  - There's heritable variation within species

  - Advantageous traits becomes more frequent over generations
• Selection pressure


  an environmental variable that acts to remove poorly adapted individuals.
• Darwin's Finches


  Adaptive radiation.

  - Galapagos Islands have 13 species of finches, but they come from 1.

  On Daphne Major

  - 1977 drought --> small seeds became rare.

  --> the finches with the largest beaks could eat the more common bigger seas.

  --> the large beaked finches survived.

  --> next generations had larger beaks.
• Peppered Moths


  - sleeps on trees at night

  - speckled grey for camouflage

  - 19th century industrial revolution meant pollution, killed light lichen on trees, so blacker moths thrived.

  - After clean air act, less polluted, lichen returned, more speckled moths and less black moths.
• Sexual reproduction


  reproduction involving the union of gametes.
• Variation


  the range of phenotypes within a population.
• Archaea


  one of the 3 domains

  - kingdoms within it: archaebacteria

  - tend to live in extreme environments

  - have RNA polymerases and ribosomes that are closer to eukaryotes.
• Hierarchy of taxa


  Did king phillip come over for good sausages?

  - Domain

  - Kingdom

  - Phylum

  - Class

  - Family

  - Genus

  - Species
• Eubacteria


  one of the 3 domains

  - has kingdoms: eubacteria

  - more diverse than archaeans.
• Vertibrate Classes


  Mammals - 4 pentadactyl limbs, lungs, internal fertilisation, live young, hairs.

  Birds - 4 pentadactyl limb (2 wings), internal fertilisation, hard egg shell, feathers, beak.

  Reptiles - 4 pentadactyl limb, lungs with folding, internal fertilisation, soft shell egg, dry impermeable skin.

  Amphibians - 4 pentadactyl limb, simple lungs, water fertilisation, soft moist permeable skin.

  Fish - fins, gills, external fertilisation, sales
• Animalia Phyla


  Porifera - sponges, no segmentation, no mouth, no anus, porous, attached to rocks, filter feeder.

  
  

  Cnideria - corals, jellyfish, radial symmetry, no segmentation, mouth, no anus, stinging cells, tentacles.

  
  

  Platylhelmintha - flatworms, bilateral symmetry, no segmentation, mouth, no anus, flattened body.

  
  

  Annelida - earthworms, leeches, bilateral symmetry, very segmented, mouth and anus, bristles sometimes.

  
  

  Mollusca - oyster, snails, octopus, bilateral symmetry, non-visible segmentation, mouth and anus, shells of CaCO3.

  
  

  Arthropoda - ant, scorpion, crab, bilateral symmetry, segmented mouth and anus, exoskeleton.

  
  

  Chordata - fish, birds, mammals, bilateral symmetry, segmented mouth and anus.
• Domains


  there are 3

  archaea

  bacteria

  eukarya.
• Eukarya


  one of the 3 domains

  - has kingdoms: plantae, animalia, fungi, protista.

  - cells are compartmentalized.
• Taxon


  a group of species which shares and evolutionary relationship.
• Dichotomous Key


  yes or no questions

  identifies unknown organisms

  
• Taxonomy


  the science of classification.
• Dog taxonomy eg.


  D - Eukarya

  K - Animalia

  P - Chordata

  C - Mammalia

  O - Carnivora

  F - Canidae

  G - Canis

  S - lupis
• Lemon tree taxonomy eg.

  D - Eukarya

  K - Plantae

  P - Angiospermata

  C - Dicoyledoneae

  O - Geraniales

  F - Rutaceae

  G - Citrus

  S - limonia
• Binomial System


  two names for an organism, written as:

  Genus, species. UNDERLINES OR ITALICS
• Viruses


  non-living biological entities that have infectious properties - non-living pathogens.
• Analogous Structures


  trait structures which are similar because of convergent evolution.

  - two separate species develop similar features, but not from a common ancestral form.

  - usually similar function but different structure.

  eg. the eye.