Biological Evolution Standard B – 5.5

What You Should Understand After This Lesson How scientific studies in the fields of anatomy, embryology, biochemistry, and paleontology have contributed scientific evidence for the theory of evolution.

Evidences of Evolution Evidence of common ancestry among species comes from many sources. Fossil Record (Paleontology) Comparative Anatomy Embryology Biochemistry (Molecular Biology)

Fossils (Paleontology) Paleontology is the study of prehistoric life. Provides valid evidence of life forms and environments along a timeline. Comparing current and ancient species shows a pattern of gradual change. Tells a story of the types of organisms that have lived on Earth.

Fossil of Horsetail from 300 million years ago.

Paleontologists work among some of the hundreds of full-sized fossils of mammals in Nebraska’s Ashfall. Nearly 12 million years ago a volcano spewed its ashes on this land burying many of the mammals. This is the only fossil bed on Earth to have full-size mammals.

Comparative Anatomy The study of the structure of organisms. Study many anatomical structures. Homologous Structures Same structure, different function Analogous Structures Same function, different structure Vestigial Structures Structures that no longer serve a purpose

Homologous Structures

Analogous Structures

Analogous Structures

Vestigial Structures

Feathers of an ostrich are considered vestigial structures. The hind legs of a whale are considered vestigial structures.

Embryology The study of embryonic development of organisms. Comparing the anatomies of embryos. An early stage of an organism: Pre-birth Pre-hatching Pre-generation

Can you tell which one is the human? The cat? The horse? The cow?

Ernst Haeckel’s Vertebrate Embryo Ontogeny Figure From left: fish, salamander, turtle, chicken, pig, cow, rabbit, human

Biochemistry Comparing the DNA and RNA of organisms to look for similarities. Studies genes and proteins to provide support for biological evolution.