Liz Schultheis Tomomi Suwa A change in a trait of a population over time generations eg H air color Disease resistance Chemical compound Tail length Frequency Beak Depth Large Ground Finch ID: 1047211
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1. Evolving to InvadeMarcia AngleLiz SchultheisTomomi Suwa
2. A change in a trait of a population over time (generations).e.g. Hair colorDisease resistanceChemical compoundTail length FrequencyBeak DepthLarge Ground FinchGeospiza magnirostrisWhat is evolution?
3. For evolution by natural selection to occur we need…Variation in the traitThe trait has a genetic basis – is passed on to offspringSome individual produce more offspring than others (i.e. Natural Selection)# offspringBeak SizeIndividual birdsEvolution of increased beak size!
4. Where does variation come from? MutationRecombinationMigration
5. Evolution by Natural Selectionevolution.berkeley.eduEvolution of body color!Trait: body colorSelection agent: birds
6. At what level does evolution occur?IndividualPopulation (a group of interbreeding individuals)Species (a group of potentially interbreeding individuals – usually includes many populations)
7. IndividualPopulation (a group of interbreeding individuals)Species (a group of potentially interbreeding individuals – usually includes many populations)At what level does evolution occur?
8. What is an invasive species?Introduced from another country by peopleGrows and takes over an areaCan harm native speciesCost people a lot of time and money
9. “Nothing in biology makes sense except in the light of evolution.” -Theodosius Dobzhansky (1973)
10. Think back to the elements necessary for evolution to occur:VariationTrait is genetic and passed down from parents to offspringSelection on the trait. Survival and ability to reproduce depends on trait value.Discussion: how will evolution affect a new invasive species?
11. There might be low genetic variation at firstBut multiple introduction increases genetic variationInvaders experience new selection in introduced rangeInvaders evolve to adapt to a new environmentDiscussion: how will evolution affect a new invasive species?
12. Game: understanding evolution in a new invasive speciesOur species – purple loosetrifeIndividual plants have seeds with different numbers of barbs, which predators can use to collect the seeds
13. Trait Variation
14. Game:109876543210 1 2 3 4 5 Number of individuals in population Trait Value (# of Velcro pieces) Graph ___ ___
15. Selection on TraitSeed predator 1
16. Game: Evolution in the native range1 A1 B1 DAverage trait =2.521 C3
17. Selection on TraitSeed predator 2
18. 2 A2 B2 DAverage trait =3.422 CGame: Evolution in the invasive range2
19. Low genetic variation at first in invasive rangeMultiple introductions increased genetic variationInvader experienced new type of selection in introduced range (from different type of predator)Invader evolved and adapted to a new environmentHow did evolution affect our invasive species?