Evidence of Evolution

Four Main Types of Evidence

1. Fossils

2. Homologous structures

3. Similar embryo development

4. Geographical distribution

Fossil Record• Fossils are evolutionary evidence

• Fossils show that ancient species share similarities with species that now live on Earth.

• Fossils records provide evidence that living things have changed over time.

Glyptodont Armadillo

Traits • Derived traits

newly evolved features, such as feathers, that do not appear in the fossils of common

ancestors.

• Ancestral traits primitive features, such as teeth and

tails, that do appear in ancestral forms.

Comparing Anatomy• Homologous structures

• Analogous structures

• Vestigial structures

Homologous structures

• Anatomically similar structures inherited from a common ancestor

• These structures can be similar in arrangement and/or function.

Analogous Structures • Structures that do not have a common

evolutionary origin but are similar in structure.

• Shows that functionally similar features can evolve independently of each other

• Ex: wing of an insect and wing of bird

Analogous Structures

Vestigial Structures • A body structure that has no function in a

present-day organism but was probably useful to an ancestor.

• This shows a change over time

EvolutionChapter 15

Comparing Embryos • Embryo: the earliest

stage of growth and development of both plants and animals

• Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult forms.

Comparing Embryos• Similar embryo development may suggest a

common ancestor

Biochemical Evidence • Common ancestry

can be seen in the complex metabolic molecules that many different organisms share.

• Comparison of the DNA or RNA of different species produce biochemical evidence for evolution

Biochemical Evidence • Comparisons of the similarities in amino acids

and other molecules across species reflect evolutionary patterns seen in comparative anatomy and in the fossil record.

Geological Distribution

• Similar animals are found in different locations around the world.

• Animals ended up evolving similar features for their environment because of their location on earth

• They look the same but live in different areas

Knowledge Check

True or False

Organisms with similar anatomy share

similar DNA sequences.

A. analogous structures

B. embryological structures

C. homologous structures

D. vestigial structures

Which features are similar in use and evolve in similar environments, but do not evolve from a common ancestor?

Knowledge Check

Knowledge Check Which of the following best explains how the fossil record provides evidence that evolution has occurred?

A It indicates the exact cause of structural and behavioral adaptations of organisms.

B It shows that the form and structure of groups of organisms have changed over time.

C It shows how the embryos of many different vertebrate species are very similar.

D It indicates that forms of life existed on Earth at least 3.5 billion years ago.

Knowledge CheckThe occurrence of the same blood protein in a group of species provides evidence that these species

a. evolved in the same habitat.

b. evolved in different habitats.

c. descended from a common ancestor.

d. descended from different ancestors.

Knowledge Check

Which is an example of a derived trait?

A. a tail

B. bones

C. feathers

D. teeth