IB Biology Topic 10 evolution and the basics of natural selection

evolution

the process of genes changing over generations

the "steps" of natural selection

genetic variation
offspring who form genetic mutation as a result of their environments have adapted (survival of the fittest)
mutated offspring go to have children and pass down adaptions to offspring

how can natural selection cause evolution in a population of organisms?

Evolution relies upon the notion that mutated traits are passed on from mutated parents that have adapted to their environment and survived in a large population. This relies on the knowledge that only those with suitable characteristics survive and reproduce, promoting the frequency of an adapted trait, which is natural selection.

what are factors that cause genetic variation in a population

mutation, meiosis, sexual reproduction

what aspect of mutation causes genetic variation?

mutation in the chromosomes causes new varieties of a gene

what aspect of meiosis causes genetic variation?

crossing over in prophase 1, independent assortment in metaphse 1

what aspect of sexual reproduction causes genetic variation?

traits are mixed with each generation of offspring

describe the evolution of beak shape/size in the finches on different islands in the Galapagos

average beak size grew

explain the evolution of beak size/shape in finches on the Galapogos islands

originally finches with larger beaks were able to outcompete finshes with smaller beaks for food, increasign the beak size that way
drought in 1977 - made frequency of larger beaks grow because there were no small seeds for smaller beaked finches to feed
surviving population of the event passed down the large beak trait

melanistic industrialization

the increase in frequency of a darker melanistic variety as a result of pollution

what was the evolution of the peppered moth population in response to environmental changes in England

greater frequency of darker, melanistic variety of peppered moths in England

explain the evolution of the peppered moth population in response to environmental changes in England

originally, before industrialization, light colored moths were more frequent becuase they were better suited to camoflauge
due to high amounts of sulfur oxide soot, the environment became darker and the melanistic variety was better suited
the better suited trait grew in frequency

describe the evolution of antibiotic resistant strains of bacteria

some bacteria will develop resistance to an antibiotic and multiply rapidly thanks to binary fission

how are mutated genes exchanged between bacteria

conjugation. plasmids containing mutations are exchanges

how can misuse of antibiotics accelerate evolution of antibiotic-resistant bacteria

when antibiotics are taken in doses higher than reccomended, there is a higher likelihood of mutations becuase the bacteria sense it in greater amounts

why does evolution occur more quickly in populations of organisms that have short lifespans + reproduce quickly

more generations so traits will be passed down quicker

example of selective breeding of domesticated animals, results

great danes: for centuries, humans have chosen the largest male and the largest female dog to crossbreed, which resulted in the Great Dane breed, known as the largest breed of dogs

example of selective breeding of domesticated crops, results

Crossing of certain traits in a plant (vitamin, number of leaves, pigmentation, etc.)has resulted in different varieties of plants that have a high frequency of said trait

homologous structures

similar structures that arise from a common ancestor

adaptive radiation

when a characteristic rapidly multiplies in a population

how do homologous structures arise by adaptive radiation

The characteristics form homologous structures will diverge when adapting to the environment and multiply by adaptive radiation

example of homologous structure

bone structure of vertabrate pentadactyl limbs

analogous structure

structures that do not arise from a common ancestor, instead similar environments

convergent evolution

two organisms develop similar characteristics due to similar environments, not a similar ancestor

example of analogous structure

wings of birds and insects