10.5 Evolutionary Biology Today

These flashcards cover the key concepts of evolutionary biology today, including fossil evidence, molecular evidence, and the unification of biological fields through evolution.

What is the definition of paleontology?

The study of fossils or extinct organisms, which provides direct, physical evidence of how life forms have changed and diversified over billions of years.

What are two reasons why the fossil record is considered incomplete?

1. Most living things do not form into fossils after they die. 2. Fossils have not been looked for in many areas of the world.

What is an example of a transitional fossil mentioned in the text?

Basilosaurus isis

Why are transitional fossils important to evolutionary biology?

They demonstrate the evolution of traits within groups as well as the common ancestors between groups.

What is the basis of DNA sequence analysis in evolutionary theory?

The more related two organisms are, the more similar their DNA will be; sequences of nucleotides in a gene change over time due to mutations.

What are pseudogenes and how do they contribute to evolutionary theory?

They are DNA sequences that no longer function but are still carried with functional DNA; similarities between pseudogenes reflect a common ancestor.

What is the function of homeobox genes?

They control the development of specific structures and indicate a very distant common ancestor.

Evidence of homeobox gene clusters has been found in organisms that lived as far back as how many years?

$600$ million years ago

What is molecular fingerprinting?

A technique that compares proteins to reveal similarities among cell types across different organisms.

What two things combine to make up modern evolutionary theory?

The theory of natural selection and genetics.

Based on molecular evidence, what is the closest living land animal related to whales?

The hippopotamus

What is meant by the phrase "Evolution unites all fields of biology?"

Basic principles of evolution are used in diverse fields such as medicine, geology, geography, chemistry, and ecology.

Describe the physical characteristics of the whale ancestor Pakicetus.

It was skinny and found it easier to walk on land.

How is the whale ancestor Ambulocetus natans described?

It had hands that made it easier to swim and possessed stronger arms.

What is the "modern synthesis" of evolutionary theory?

The theory of natural selection supported by genetic evidence.

Why is Basilosaurus isis considered a transitional fossil?

It had a whalelike body but the limbs of a land animal.