Theory of Evolution Diversity of life “Change over time”

Origins of Evolutionary Thought Spontaneous generation – life can arise form nonliving material Redi and Pasteur used controlled experiments to disprove this idea Primordial Soup – Urey and Miller simulated early conditions on earth and tried to form complex organic compounds (all life is made up of organic compounds). They made amino acids Biogenesis – life only arises from existing life It has been accepted for over 100 years

ADD MORE RECENT RESEARCH RNA was formed from earth’s early atmosphere RNA and DNA make amino acids (first biological molecule) which link together to make proteins.

Origins of Evolutionary Thought Jean-Baptiste Lamarck—1809, proposed his hypothesis on the inheritance of acquired characteristics. He said that by use or disuse of organs, organisms acquired or lost traits during their lifetime. These traits could be passed to their offspring. Slowly the species would change. Ex:Parents are bodybuilders, therefore their children will be born with big muscles.

Charles Darwin Evolution was first described by Charles Darwin in his essay “Origin of Species” written in Most of his ideas about natural selection came from a much earlier voyage he took aboard the HMS Beagle, especially in the South American Galapagos Islands.

Geologic Time Scale

Spindle diagrams – show evolution of groups of organisms

How do we know this? Paleontology Fossils provide a record of evolutionary history, and show how things have changed over time. The fossil record is by no means complete, but our understanding of evolution becomes more complete as more fossils are found each year.

Fossils (continued)

Where do we find fossils? Sedimentary rock builds up over time. Paleontologists may recover the fossil at a much later time in history.

Relative Dating: As layers are added it puts fossils in their order of existence. Index fossils are easy to recognize and have known time periods so they are useful in determining how old that layer is. Ex. trilobites

Can tell which organisms are the oldest, most recent, which have survived the most amount of time, which covered the largest ecological range, which locations have eroded.

Anatomy Examining various anatomical features provides some evolutionary clues. Homologous structures Analogous structures Vestigial structures

Homologous Structures Homologous Structures—Structures with a common evolutionary origin. Homologous structures demonstrate divergent evolution—organisms that have a common ancestor and were once very similar have become different over time

Homologous Structures

Analogous Structures Analogous Structures—similar structures on very unrelated species. They don’t have a common origin (no common ancestor) but demonstrate adaptation to similar environments. Analogous structures demonstrate convergent evolution—organisms that don’t have common ancestors and were once very different have become more similar over time.

Vestigial Structures Vestigial structures—structures/organs that serve no function in the modern species but were useful to an ancestor. The existence of vestigial structures demonstrates change over time.

Vestigial Structures Blind cave salamander (still has remnants of eyes) Pelvic bones/femur in whale

Embryology

Biochemistry Biochemistry—The study of the chemistry of living things. Similarities in the DNA, RNA, and protein structures in species shows evolutionary relationships. The more similar the DNA, RNA, and protein the more closely related the organisms are.

Adaptations Adaptations amongst different organisms in different climates/environments show how species change over time to fit their environment. Ex: Camouflage, mimicry

Evolution Species change over time  they evolve Takes a long time (thousands to millions of years for the change to happen) Spontaneous mutations lead to natural selection Some organisms are more fit for survival than others

Classification Need a way to organize all of the information we have. Millions of species of living things on our planet today

6 Kingdoms of Life