organic evolution exam 2 study guide
solutions
For allele frequencies to change there has to be: - ANSWER-variation (there have to be different
alleles)
Variation in a population comes from : - ANSWER-Mutation
Gene Flow
Once genetic variation has been established, what causes the allele frequ...
Dark-colored moths flourished because of their ability to hide on the darkened trees.
They left more offspring
Stabilizing Selection - ANSWER✔✔-Individuals with extreme phenotypes die or fail to reproduce
resulting in populations of individuals with intermediate phenotypes.
Most common in stable, unchanging environments where selection has remained the same for years.
disruptive selection - ANSWER✔✔-extreme phenotypes become more frequent from generation to
generation because they survive to reproduce while individuals with intermediate phenotypes die or fail
to reproduce.Diversifying selection results in polymorphism (two or more different forms are common).
ex.)taurus scarab beetles-one shows head spines the other does not Males with elaborate horns or
antlers may attract more mates but die younger because they are costly to grow, make the animal
clumsy and more obvious to predators. Males without elaborate horns or antlers attract fewer mates but
live longer.
Example of Tracking Natural Selection Affecting Quantitative Traits - ANSWER✔✔-Use survivorship or
number of offspring as an approximate measure
ex) beak of finch-
Step 1: Capture weigh, measure, and identify hundreds of the birds and record their diets of seeds
Step 2: For the seeds the finches eat, measure seed size and seed hardness
Page 4/53
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Emillect. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.49. You're not tied to anything after your purchase.
