Types of fossils
Imprints- Imprint of a leaf, feather, or organism in rock.
Molds- is a fossilized impression made in any material - a negative image of the organism
Casts- made of minerals that filled the hollows of an animal track, mollusk shell, or other parts of an organism.
Petrified- A piece of wood or bone replaced by minerals. Amber- An insect or other organism trapped in plant resin.
Sedimentary rock
A rock type formed by mud, sand, or other fine particles that settle out of a liquid.
The layer that contains the most fossils.
Examples of sedimentary rock: limestone, sandstone, and shale
Fossils are most commonly found in limestone.
Other evidence for evolution
Homologous structures- Traits that are similar in different species because the species share a common ancestor
How are the human arm, whale fin, and bat wing similar?
• All three organisms have bones for the forearm and digits.
Vestigial structures Vestigial structures-
Inherited structures that are reduced in size and are often unused.
Suggest structures that once functioned in an ancestor
Example; Pythons have vestigial hip and leg bones which indicates a legged ancestor.
Examples: Human appendix, a tiny dead-end pouch on the intestine that may play a minor role in the immune system. The Muscles that move the ear.
Analogous structures
Analogous structures-Those structures that are similar in function, but not inherited from a common ancestor.
• What are some examples of these types of structures?
Embryological development
• In early development, tails and gill slits are found in fish, rabbits, birds, and mammals.
DNA • Scientists can determine if an organism is related to another organism by comparing their DNA.
• Organisms that are close relatives have similar DNA.
• Dogs are the closest relative of bears
• Genetic evidence shows that all Primates (including us) evolved from a common ancestor