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Evolution- “Change Over Time”. All of the changes that have occurred in living things since the beginning of life on Earth. History of the Earth. Three important points…. Evolution occurs over MANY generations Evolution occurs within POPULATIONS (NOT individuals)
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Evolution- “Change Over Time” All of the changes that have occurred in living things since the beginning of life on Earth
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
In other words… • Sometimes we see structures in two species that are similar…some of them are: • Homologous (they are similar because of a common ancestor) • Analogous (they are similar because althouth they do NOT share a recent ancestor, they live in similar environments and have adapted to them similarly)
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