PRITCHARD Flashcards
What is diversity
consequence of non-random survival of randomly varying replicators
What is the difference between micro and macro evolution
MICRO = change in gene frequency MACRO = formation of new species
What are the main points of Darwin’s theory of evolution
- not all survive
- individuals vary
- differences inherited
- more individuals produced
What is the great chain of being
Hierarchy believed by Christians, covers all matter of life:
- idea of progress
- evolution goes in a direction
- complex is better
- aims for ideal form
- dead things would be at the bottom of ladder
What is Linnaeus classification
- Principle of ideal forms
- Studying the natural world enables you to know god better
- Gives binomial species definition
- Species defined by phenotype
What is intelligent design
‘An evident based scientific theory about life’s origins’
Claimed that complexity cannot have come about by natural selection and must have come from intelligent cause (e.g. watch clearly been designed to tell the time)
What is irreducible complexity
Believes that many biological systems could not have evolved for their function by natural selection, they were designed to do their job – theory rejected by scientific community.
If you take away one piece of a watch it would cease to function
Define exaptation (AKA preadaptation)
the process by which features acquire functions for which they were not originally adapted or selected e.g. feathers of a bird
Why has there been an emergence of change
Society
- industrial revolution
- dangerous both physically and politically
Fossil record
- transitional forms identified
- find animals not mentioned in bible
Scientific progress
- Galileo removed Earth from centre of universe
- discovery of microscopes revealed new worlds
Age of Earth
Sam Fancies Sam Adler
Define catastrophism
The theory that changes in the Earth’s crust during geological history have resulted chiefly from sudden violent and unusual events
Define uniformitarianism
The theory that changes in the earth’s crust during geological history have resulted from the action of continuous and uniform processes
What were the similarities and differences between Lamarck and Darwin
Similarities
- gradual process
- driven by environment
- predicts gradual change and needs long time
Differences
D: Change due to mutation
L: Change not due to chance
D: No increasing complexity
L: Increasing complexity
D: No internal desire to improve
L: Internal desire to improve
D: Only whole populations evolve
L: Individuals evolve
D: Do not inherited acquired characteristics
L: Do inherit acquired characteristics
L wrong because tattoos and scars not inherited
What did Darwin learn in the Galapagos
- succession of types
- representative types - variation and geographical isolation, ecological niche, convergent evolution
- large amount of continuous variation
- ocean islands migration and common descent
Define a biological species
A group of organisms that can interbreed and produce viable and fertile offspring
What is allopatric speciation
Physical separation
Differences between species occur over time
Reproductive isolation occurs
What is are pre and post mating isolation mechanisms
Premating - transfer of gametes prevented
Postmating - gamete development prevented
Pre:
- habitat isolation - same area, different habitat
- temporal isolation
- ethological isolation
- behavioural isolation - same area, wrong marine behaviour
- mechanical isolation - same area, wrong structure
- gametic isolation
Post:
- reduced hybrid viability - sheep mates with goat = zygote dies before birth
- reduced hybrid fertility - horses and donkey = mule however mule is sterile
- hybrid breakdown
- gametic incompatibilty
What are the 4 concepts of species
- Ecological - defines species as a group of organisms that are adapted to a specific collection of resources (a niche) in an environment
- Biological - separates species based on the degree of genetic exchange between gene pools
- Genealogical - evolutionary history and taxonomy of organisms
- Morphological - defines species based on physical characteristics and traits
What is anagensis and cladogenesis
Anagensis - species formation without branching of the evolutionary line of descent
Cladogenesis - one species splits in two
What are the 3 steps to speciation
- Gene flow between 2 populations is interrupted
- Genetic differences gradually accumulate between 2 populations (mutation, founder effect, natural selection)
- Reproductive isolation evolves as a consequence
What are the 3 types of selection
Stabilising
- two extremes around the fittest phenotype
- selection pressures different on each side
Directional
- only fit at 1 extreme
- 1 extreme becomes more favourable
Disruptive
- the mean becomes less fit, fitter at extremes (dip in middle of graph)
How is variation maintained
- Different selection in different areas/ times
- Heterozygote advantage (sickle cells gives malaria resistance)
- Frequency dependent selection
- Immigration can maintain genes against selection
- Mutation maintains variability
What are the advantages and disadvantages of sexual reproduction
A: generate variation
D:
- genetic diseases passed on
- don’t get to choose which genes are passed on, could lose good one
- expensive/ energetic and dangerous to find a mate
- males are ‘waste of space’, parthenogenic people would outstrip those who reproduce sexually because they don’t need males
What is group selection
- groups with lower extinction/ higher speciation increase
- groups with a given adaptation go extinct at a lower rate
- restraining of food intake by group allows survival
- groups that don’t restrain go extinct
What problems arise from living on land for plants
- desiccation (removal of moisture)
- separation of water source from supply
- nutrients - evaporation, until a cuticle developed water lost
