Evidence for Evolution

•Fossil= any remains of life from an earlier time.

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.

Here's a general flow chart of fossil formation:

                                                                 

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

Camouflage vs. Mimicry

• Adaption for defense in which one organism blends into it’s surrounding

• Resemblance of one organism to another, this is also used as a defense.