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Evolutionary Relaitonships

Minoshka Bocarro Biology Victorian Certificate of Education (VCE) English

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Patterns of Evolution
- Divergent
  - Adaptive radiation
    - rapid divergence
  - Speciation
    - Allopatric speciation
      - Move into new environment
        Geographic isolation
        Diff selection pressures
        Reproductive islation
    - Sympatric speciation
      - Mechanical isolation
        Structural diff
      - Behavioural isolation
        Diff in behaviour of similarspecies
      - Ecological isolation
        Habitat selection - niche
      - Hybrid
        Sterility
        Infertile
        Inviability
        Die early on
      - Polyploidy
        Sudden speciation through reproductive isolation
      - Within niche preferences
    - Reproductive isolation
      - Prevention of interbreeding
    - Gradual
      - Geo isolate
        Races
        Species
    - Rapid
      - Founder pop
        Small
  - Diff. species from common ancestor
- Convergent
  - Parallel
    - Related species
  - Unrelated
  - Independently develop similar features
    - Similar selection pressures
- Races
  - Genetic diff.
    - Geographic range
      - Maintain distinctiveness but interbreeding occurs
Evolution
- Gene Pool
  - Changing frequency of alleles
    - Over time
    - Survival
    - Abundance
    - Population
      - Group of same species living in same area
- Modern Theory
  - Selection
    - Acts on existing variation
    - Natural Selection
      - Natural environment exerts selection pressures
        Struggle to survive
        Dependent on fitness value
        Higher -> advantageous traits
        Increased likelihood of survival
        Offspring receive alleles for advantages trait
        If express in phenotype
        Higher liklihood for survival
        Frequency Increases
        Greater proportion of advantageous
        Heterozygote advantage in sickle cells
        Best suited to environment in comparison with other phenotypes
        Compete
        Food
        Living Space
        Mating Partners
        Avoid predation
        Avoid disease
        Abiotic & Biotic in external and internal environments
      - Over time
    - Adaptation
      - Inheritable suitable characteristics to an environment allowing to survive & reproduce
  - Small population
    - Chance events have greater effect
      - Genetic drift
        Chance effects
        Change in gene pool
        Bottleneck
        Catastrophic event causes pop size to dramatically reduce
        Reduce Gene pool
        Natural disaster
        Founder effect
        Low number
        Sample (unrepresentative)
        Collonise new area
        Limits variation
        Missing alleles
        Frequency = 0
        Fixed alleles only
        Frequency = 1
  - Non-random mating
    - Sexual reproduction
      - Certain alleles in a pop increase in frequency
        Produces descendant pop
      - Independent assortment
      - Pass on genes
      - Excess of potential offspring ensure more will survial
    - Sexual selection
  - Variation
    - Polymorphism
      - Shuffles existing Variation
        Genetic recombination
        Crossing over
      - Germline Mutation
        Changes in base sequence of DNA that change amino acid sequence and thus proteins. Can be inherited
      - Many forms of a trait
    - See in
      - Structural
      - Behavioural
      - Biochemical
      - Physiological
      - Developmental
  - Gene Flow
    - Migration
      - Rate of Migration
    - Introduce new alleles into a pop.
      - Changes allele frequency within pop
      - Loses alleles if unrepresentative sample
- Hardy-Weinberg equilibrium
  - Random Mating
  - No selection
  - Large pop
    - Reduce chance effects or genetic drift
  - No mutations
  - No gene flow
  - No evolution to occur
- Microevolution
  - Elements of Modern Theory
- Macroevolution
  - Speciation
Evidence of Evolution
- Fossil record
  - Direct evidence of past life
  - Preserved remains, traces or impressions in rocks
  - Info on simple structure, extinct species and divergence
  - Formation
    - Hard parts
    - Immediately burried
    - Sedementation
      - Covered with sediments and compressed
    - Frozen over
  - Types
    - Mineralisation
      - Replacing fossil with minerals
    - Impression fossil
      - Organism dissolved away leaving imprint
    - Trapped in amber
    - Preservation in volcanic ash and quicksand
    - Trace fossils
  - Relative dating
    - Stratigraphy
      - Using strata to compare relative age if above or below layer
    - Index fossils
      - Distinctive and abundant. Wide geo. distribution for only a short period. Rocks of known age
  - Absolute dating
    - Radioactive elements decay
    - Radio carbon dating
      - 14C isotope to 14N isotope
      - All living organisms have set carbon
      - Short half life
    - Potassium to argon and uranium to lead
    - Thermoluminescence
      - emission of light from mineral when heated proportional to radiation absorbed
        Length of time since object was heated
  - Geological Time Scale
    - Cenozoic
      - Current
    - Mesozoic
      - Repitles
        Cretaceous extinction
- Biogeography
  - Geographic distribution of organisms
    - Continental drift
      - Gondwana
        Similar species spread over hemisphere
      - Plate tectonics
- Comparative Morphology
  - Homologous
    - Analogous
      - No common ancestor
      - Appear similar
        Perform similar function
        Independently evolved from environmental pressures
    - Fundemental similarity
    - Evolutionary relationship
      - Common ancestor
    - Perform diff. functions
      - Diff selection pressure
  - Comparative embryology
    - Same pattern during embryonic development
      - Features common develop early
        Longer look alike, more closely resemble
    - Biogenetic law
  - Vestigial structure
    - Left over from past
      - No apparent function at present
        Resemble structures found in other organisms and ancestors
        Not harmful thus no selection pressure against
  - Sim and diff in structure
- Molcular Evidence
  - Amino acid sequence
    - Evolutionary history
      - Reflect changes in DNA
        Degenerate
  - DNA-DNA hybridisation
    - Overall genetic similarity
      - The more similarity, more H-bonds formed, stronger it is, the more heat it takes to separate, the closer to separation temp
        Degree of diff from 87 degrees is 1 % diff
  - Gene sequencing
    - Order of nucleotides
      - Chloroplast= highly conserved
      - Nuclear - Vary in size
      - DNA coding rRNA - repetitive DNA sequences, highly conserved, useful diff organisms compared
  - Molecular homology
  - Universal
Determining Evolutionary Relationship
- Comparitive Genomics
  - Using techniques for molecular analysis to study and compare entire genome of diff organisms
- Comparison
  - Mitochondrial DNA
    - Small length
    - More discrete gentic change
    - No recombination
    - more copies avaliable
    - Mutates at high rate in humans and other animals
      - Useful in recently diverged organisms 20 mill
  - Molecular clocks
    - Rate of mutation used to tell divergence
      - Unreliable- fossil dates and diff rate of genes
- Phylogeny
  - Extinction
    - Pseudoextinction
      - Disappearance of ancestral form but daughter form continues
    - Inability to cope with particular enviroment
    - Mass extinction
    - Background
  - show evolutionary relationships from common ancestor
    - Rooted
      - Similarity of organism
      - Node
        Time of divergence
        Common ancestors
    - Unrooted
      - Only relationships

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Description: Victorian Certificate of Education (VCE) Biology (Unit 4 AOS 2 - Evolution) Mind Map on Evolutionary Relaitonships, created by Minoshka Bocarro on 08/09/2016.
Created by: Minoshka Bocarro
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Evolutionary Relaitonships

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