Evidence of Evolution Notes

A scientific theory explains why something happens in nature and is supported by lots and lots of evidence.

Charles Darwin and many other scientists contributed to the development of this theory that explains how organisms change over generations to best thrive in the environment they live in.

A fossil is any preserved remains, impression, or trace of an organism from the past.

How Fossils Supports Theory of Evolution

• Fossils provide a snapshot of the past

• Fossils can directly show how a species has changed over time

• Oldest fossils are on the bottom layers of the Earth's crust giving us an idea of what time period they lived.

Comparative Anatomy looks at similarities/differences within structures/parts of an organism
There are 3 main categories (to be discussed on next slides):
1. Vestigial Structures
2. Homologous Structures
3. Analogous Structures

Vestigial Structures:
Structures or features that many living organisms have, but no longer serve their original purpose due to evolutionary changes.


How it supports? They are "leftovers" from a past common ancestor. Used the hypothesize relationships among species.

Homologous Structures:
Features that are similar in structure but have different functions in different organisms


How it Supports? Scientists theorize that animals with similar structures likely evolved from a common ancestor

Analogous Structures:
A structure that perform a similar function but do NOT have a similar origin.


How it supports? These types of structures evolve differently and usually in response to best suit the environment the organism lives in.

A branch if science that compares and contrasts embryos of different species and the patterns of their development.

An embryo is an early stage of development of an organisms

This line of evidence is "newer" because of recent technological advances

How Comparative Embryology Supports Theory of Evolution

• All vertebrate (organisms with a backbone) embryos develop in identical patterns to produce tissues and organs

• Similar patterns of embryological development provide evidence that organisms evolved from a common ancestor

Biogeography is the study of the distribution of organisms on Earth today and over time.

How Biogeography Supports Theory of Evolution

• Patterns of distribution of fossils (where the fossils are found) tell us how organisms evolved from ancestors

• Today, most species on the same continent are more closely related than organisms on different continents.

DNA sequences can be used to determine how closely related organisms are to each other.

Remember, all living things on Earth share the same universal code in DNA and RNA molecules

How Molecular Biology Support Theory of Evolution

• Species with similar DNA sequences share a more recent common ancestor and are more closely related

• This line of evidence is "newer" because of recent technological advances