evidence of evolution

What are the 5 types of evidence for evolution?

1. Homologous structures, 2. Vestigial structures, 3. DNA evidence, 4. Embryological development, 5. Fossil record.

What is the difference between homologous and analogous structures?

Homologous structures share a common origin (similar structure) but may have different functions due to divergent evolution. (Note: Analogous structures have similar functions but different evolutionary origins).

What does a vestigial structure suggest about an organism's history?

It suggests the structure was important to an ancestor but has since been reduced in size and function because natural selection selected against the trait.

Given the DNA or amino acid sequence of different animals, be able to determine which animals are more closely related to each other.

Animals that are more closely related exhibit a higher degree of similarity in their DNA or amino acid sequences.

If shown a picture of different animal embryos with similar development, what does this imply about their ancestry?

It implies that they share a common ancestor.

Why is having a fossil record useful? What are its limitations?

It is useful for giving us a fine scale of how long evolution takes and showing similarities between extinct animals and animals alive today. (Limitations are not explicitly defined in your notes, but the record is generally understood to be incomplete).

What are the two models that describe the speed of evolution?

Gradualism and Punctuated Equilibrium.

Given a picture, be able to determine if the evolutionary change is following the gradualism or punctuated equilibrium model.

Gradualism is shown by slow, steady changes over a long period. Punctuated equilibrium is shown by long periods of no change punctuated by short periods of rapid and substantial change.

Genetic drift is more likely to occur under which model: gradualism or punctuated equilibrium?

Punctuated equilibrium (because it is triggered by events like the isolation of small populations).

Homologous structure

Parts of the body that are similar in structure (same origin) but have different functions; occurs because of divergent evolution.

Vestigial structure

A structure that has been so reduced in size and function that it is no longer used, because natural selection selected against this trait.

DNA evidence

Species that share a closer evolutionary relationship will exhibit a higher degree of similarity in their DNA.

Embryological development

When embryos of different species develop in very similar ways, it signals that they have a common ancestor.

Fossil record

Preserved remains of organisms that give us a fine scale of how long evolution takes and show similarities between extinct animals and animals alive today.

Gradualism

Changes happen slowly and gradually over a long period of time, rather than suddenly or in large leaps.

Punctuated equilibrium

Species often experience long periods of time of no change, punctuated by relatively short periods of rapid and substantial change