Natural Selection
What does heredity mean?
Offspring get their traits from their parents.
Name three pieces of evidence for evolution.
Embryos, DNA, fossils, geographic distribution, homologous structures, vestigial structures.
Define speciation.
When one species becomes two or more species that can no longer reproduce successfully.
What’s the difference between a law and a theory?
Not much. Both have lots of evidence. Laws are more narrow and theories are broader ideas.
What does variation mean?
All organisms in a population are different from each other due to random mutations.
How are fossils useful evidence for evolution?
We can organize fossils from oldest to most recent and see how organisms have changed over time.
Which type of speciation is this?
One species of finch was living on the island. However, there was a lot of competition for the same type of food. Over time, two species of finches evolved so that each specialized in specific types of seeds.
Competition Reduction
What is wrong with Lamarck's theory?
Changes that happen to an organism during their lifetime are not passed onto the offspring.
Organisms cannot change because they NEED or WANT to change. It happens due to random mutations.
Name two adaptations that the botfly has and how it helps it with natural selection.
Examples:
1. Barbs that prevent it from being pulled out-- survive.
2. Produce antibiotic to prevent infection-- survive
3. Eggs hatch when they sense heat from host-- reproduce.
Explain how geographic distribution is evidence for a common ancestor.
Geographic distribution shows that where organisms live today is directly related to where their ancestors lived long ago when the continents were closer together.
Which type of speciation is this?
The pygmy three-toed sloth lives on Isla Escudo de Veraguas, off the coast of Panama, where it is has evolved to have a smaller body than brown-throated sloths on the mainland. They were separated from the mainland population 8,900 years ago.
Geographic Isolation.
Why is genetic diversity important for a population of organisms?
If there is a change in the environment, genetic diversity in a population makes it more likely that at least some of the organisms will survive.
Why are mutations important for natural selection?
They create variation within a population. This variation makes it so that some organisms are better fit for their environment than others.
What are homologous structures?
Homologous bones have the same basic shape in the same place across various species, suggesting they share a common ancestor.
Which type of speciation is described in this scenario?
Two pine species grow on the Monterey peninsula. One releases pollen in February and the other releases pollen in April.
Temporal Isolation.
Why does separation lead to speciation?
Define natural selection.
Organisms that are best fit for their environment are more likely to survive and reproduce.
What are vestigial structures? How are they evidence for a common ancestor?
Vestigial structures are remains from early ancestors, but are no longer needed, suggesting that they evolves from an ancestor with that structure.
Which type of speciation is this?
Different species of crickets only respond to specific mating songs.
Behavioral Isolation
True or False. Being strong is always a helpful trait to an organism.
False. It depends on the environment.