evolution of organisms Flashcards
what is natural selection
nature favours individuals reproductive success in populations
what is evolution
theory that describes changes in species over time and their shared ancestors
sf ( changes in genetics of species)
what is a theory
explanatory model that accounts for a very large body of evidence
what is step 1 of natural selection
there is variety in a population,
what are the reasons there is variety in a population?
meiosis, crossing over, sexual reproduction, mutations
what is step two of natural selection
more offspring are produced than can survive ( only best suited can survive)
what is step 3 of natural selection
there is struggle for survival ( competition, diseases, natural disasters)
what is the fourth step in natural selection
organisms that are the fittest survive, the unfit die and do not reproduce
What is the fifth step in natural selection
The population changes over time, if isolated they may develop into different species
What is the sixth step in natural selection
Natural changes in the environment cause changes in the way that organisms survive - change in behaviour lead to physical changes
What does the term fitness mean
Suitability for survival in the environment
What does the term success mean
Ongoing potential for survival.
Adaptation
Physical feature of an organism that contributes to its survival
Viability
Able to survive and have offspring
What is a Genotype
Particular alleles represented in an individual for a trait (what it is)
What is a phenotype
Physical conditions caused by the activity of genes ( what shows)
What is a Genome
Genetic makeup of a species
What is a gene pool
All the alleles of population together expressed as a fraction of the total of each gene type
What is a Mutation
Change in the genetic code of an allele
What are the types of mutations
Neutral mutations, harmful mutations, beneficial mutations
What is speciation
The formation of new species
What are species
All members of a population that can interbreed
What is allopatric speciation
Formation of new species as results of evolutionary changes following geographic isolation
What is Sympatric speciation
New species evolved from within large populations. Sudden or gradual
What is reproductive isolating mechanism
Behavioural, structural or biochemical trait that prevents reproduction
What is directional selection
Favours individuals with more EXTREME VARIATION of a trait (giraffe necks)
What is stabilizing selection
Favours The AVERAGE PHENOTYPE within a population
What is disruptive selection
Favours individuals with variations at OPPOSITE EXTREMES of a trait
Sexual selection
Favouring a trait that specifically I handed mating excess
What is artificial selection
Controlled captive breeding process (dogs)
What is accidental selection
Human activity has introduced features disrupting the environment
What is genetic drift
Changes to allele frequency as a result of chance
What is genetic bottleneck effect
Dramatic reduction in population resulting in loss of genetic diversity
What is the founder effect
Some separate from original population and make their own
What is adaptive radiation
Rapid evolution a single species into many new species
What is divergent evolution
Large scale evolution of a group into many different forms
Competition between species is minimized
Species continue to evolve until resources are used increase in biodiversity
What is convergent evolution
Evolution of similar traits in distantly related species
Sharks and dolphin
What is coevolution
One species evolves in response to another species evolving
What is the theory of gradualism
attributes large evolutionary changes in species to accumulation of many small and ongoing changes and processes
What is the theory of punctuate equilibrium
Attributes the most evolutionary changes to relatively rapid spurts of change followed by long periods of little or no change
What are fossils
Ancient remains impressions or traces of an organism
