Evolution- “Change Over Time” All of the changes that have occurred in living things since the beginning of life on Earth
700 million years ago… MULTICELLULAR ORGANISMS!
Three important points… • Evolution occurs over MANY generations • Evolution occurs within POPULATIONS (NOT individuals) • Evolution involves genetic changes in a SPECIES • (Members of a species interbreed to produce healthy, fertile offspring)
FOSSIL EVIDENCE-Provides TRANSITIONAL LINKS Archaeopteryx- links reptiles and birds Therapsids- mammal-like reptiles
Anatomical Evidence HOMOLOGOUS STRUCTURES structures that are similar because they were inherited from a COMMON ANCESTOR ANALOGOUS STRUCTURES similar in function, but NOT inherited from a common ancestor NOTE: similar structure, but NOT always function! NOTE: similar FUNCTION, but not STRUCTURE
More Anatomical Evidence:Vestigial Structures Vestigial Structures are undeveloped structures that were functional in some ancestor, but are no longer needed in that organism.
BIOGEOGRAPHICAL EVIDENCE • When we study the distribution of plants and animals on the planet, we notice: • Animals evolved differently in each of the biogeographical regions • We see evidence that as the continents drifted, organisms were separated and evolved.
BIOCHEMICAL EVIDENCE • Almost all living things use the same biochemical molecules • DNA, Protein, ATP • Vast diversity came about by only slight differences in the same genes • The more closely “related” the organisms are, the more similar their DNA
Other Evidence… • 1. Mimicry and Camoflauge • 2. Antibiotic Resistance