Genetics And Evolution Test Revision Flashcards
(18 cards)
What are homologous structures and how are they used as evidence for evolution
Body parts similar in structure, with different functions, suggesting the organisms shared a common ancestor.
Through divergent evolution and natural selection shaping the use of the structures, they adopt different functions.
What are analogous structures and how do they provide evidence for evolution
Different structure, similar function body parts that show how natural selection has caused convergent evolution. Provide evidence that evolution is driven by emotional pressures.
What are vestigial structures and how do they provide evidence for evolution
Body parts that once held function in an ancestor but are no longer used. Demonstrates that organisms have changed over time, display common ancestry, and how a lack of selective pressures contribute to the formation of certain traits.
How are fossils evidence for evolution
Show changes over time in response to different environments, reveal transitional forms, show structures that suggest common ancestry, and rock layers can reveal the order in which species appeared and changed.
What is Darwin’s theory of evolution
Species change over time through natural selection. Individuals with traits that aided survival were better suited to their environments and could better survive thrive and reproduce
Lamar is theory of evolution
That organisms acquired characteristics over their lifetime that were then passed on to offspring.
What is natural selection
The process in which organisms with traits more suitable to their environments could better survive thrive and reproduce, passing on these advantageous traits to their offspring, leading to the evolution of populations over time
What are selective pressures
Environmental factors that influence which traits are more favourable and likely to be passed on
What is genetic variation
The differences in dna sequences of individuals within a population
Why is genetic variation essential for evolution
Provides raw material for natural selection to act upon, as natural selection needs variation. It allows some individuals to pass on their beneficial genes to the next generation, if the environmental selection pressures change.
What is the competition in natural selection
The struggle amoung organisms for limited resources, where individuals with advantageous traits are more likely to survive.
Types of evolution
Divergent: a species evolves into many distinct species
Convergent: the evolution of similar traits in similar environments even if not closely related
Parallel: when species evolve similar traits independently
Coevolution: when changes in one species drives change in another. Predator and prey
What is speciation
The evolutionary process where a population evolves into many distinct species, usually due to reproductive isolation.
Steps in speciation
- Variation
- Isolation- species prevented from interbreeding, limits gene flow, creates differences not present in other species
- Selection
Sources of genetic variation
Mutations- a change in dna sequencing, occurs randomly or bc of radiation or chemicals
Recombination- the formation of gametes, where the mixing of alleles during meiosis can create unique gene combinations within a sperm or egg before fertilisation
Fertilisation- the combination of 2 sets of dna during fertilisation to create a genetically unique individual
Other types of evident to support evolution
Genetics- comparing dna sequences of organisms to provide evidence of a species relationship to a common ancestor.
Geographical distribution-
