Evolution Flashcards
What were Darwin’s observations?
Organisms make lots of offspring
Populations stay fairly stable in size
Offspring are similar to parents
No 2 individuals are the same
What were Darwin’s conclusions?
There is a struggle for existence
Therefore, some must be more suited to survive and reproduce.
Speciation (5 steps)
Population shows variation due to random mutation
Population becomes isolated
Environment is different for population
Selection of best features are passed on to offspring in reproduction
The proportion of the individuals with the useful adaptation increases
How long does evolution take?
Many generations
What does speciation mean?
Organisms have become so different that they can no longer reproduce to produce fertile offspring.
Pesticide resistance example of evolution
Population shows variation (some mutated=resistant)
Pesticide applied=some pests killed
Surviving pests reproduce and pass on resistance to offspring
Pesticide is reapplied
The proportion of resistant pests increases
Antibiotic resistance example of evolution
Variations, due to mutations, in resistance means some are more susceptible.
Antibiotic is used, only most resistant survive
Bacteria reproduce, passing on resistance gene.
What are some behavioural adaptation of xerophytes?
Close stomata
Open stomata
Fold leaves
What are some physiological adaptation of xerophytes?
Rigid/folded stem in saguaro cactus
What are some anatomical adaptation of xerophytes?
Shallow and widespread roots Deep roots Fleshy stem/leaves Small leaf surface area Thick waxy cuticle Curled/folded/hairy leaves Stomata sunk in pits
Why may organisms from different taxonomic groups show similar anatomical features?
Although they have a different phylogeny they have evolved to live in similar conditions
What is the definition of variation?
The differences shown by organisms
The presence of variety
What is variation within a species called?
Intraspecific variation
What is variation between species called?
Interspecific variatation
What does heritability mean?
How much of a characteristic is inherited
What are the 5 ways to measure variation?
Mean Mode Median Range Standard deviation
What do you use to see significant differences in data?
Statistical tests
What are the 3 statistical tests?
Student’s t-test
Spearman rank correlation coefficient
Chi-squared test
What is a null hypothesis?
Statement that goes with t-test
what does H0 mean?
There is no difference between the sets of data
What is the critical value?
Acceptable difference between the sets of data
What is the statement you make after doing the student’s t-test if the null hypothesis was wrong?
The null hypothesis is incorrect as our value of __ is higher than the critical value. There is a difference between the ____________
What is the statement you make after doing the student’s t-test if the null hypothesis was correct?
The null hypothesis is correct as our value of __ is lower than the critical value. There is not a difference between the ____________
When is the degrees of freedom used?
When looking up the critical value
What is the degrees of freedom equation?
nA+nB-1
Which column do you normally use when looking up the critical value?
5% doubt column
What is the definition of phylogeny?
The evolutionary relationship between organisms
What is the definition of adaptations?
A feature that enhances the survival and long-term reproductive success
What is the definition of an anatomical adaptation?
Structural feature that aids survival/ reproductive success
What is the definition of a behavioural adaptation?
A way of behaving that aids survival/ reproductive success
What is the definition of a physiological/ biochemical adaptation?
Changes to the function of cell processes that aids survival/ reproductive success
What is an example of an anatomical adaptation?
Giraffe’s long neck
What is an example of a physiological adaptation?
Haemoglobin in in different animal = different affinity
What is an example of a behavioural adaptation?
A mating call (birds)
What is the evidence for evolution?
Fossil
DNA
Molecular
What are the examples of fossils as evidence for evolution?
Fossils of horses
Archaeopteryx - shows link between dinosaurs and birds
Armadillo and glyptodont - compare fossils to living things
What is the example of DNA as evidence for evolution?
Look at sequence and compare, similar=more closely related
What are the examples of molecules as evidence for evolution?
Prokaryotic/eukaryotic RNA polymerase
Similarities evolve from the same place
Cytochrome C
DNA polymerase
Why might different islands produce birds with different beak shapes?
Different islands = different availability of food sources for the birds.
What did Alfred Russel Wallace contribute to?
The biogeography - the study of why organisms live where they do
How has fossil evidence improved our understanding of evolution?
Very ancient fossils simple and unicellular showing life has become more complex
Fossils show gradual change (transitional fossils)
Confirms ecological links (land animals are reliant on land plants)
What name is given to structures with a common evolutionary history?
Homologous structures
What name is given to the process that creates variety from one basic structure?
Divergent evolution
Definition of genetic variation?
Difference between the genomes of individuals within a population
Definition of selection pressure?
Any environmental condition that favours the survival of some alleles over others.
What are analogous structures?
Similar structures even though the organisms aren’t closely related
What kind of evolution causes analogous structures?
Convergent evolution
