Presentation on theme: "Evolution A population changes over time. Charles Darwin (1809- 1882)"— Presentation transcript:
Evolution A population changes over time
Charles Darwin ( )
Lamarck- Inheritance of Acquired Characteristics
Must be Genetic You cannot “ force” yourself to have a characteristics Ex. You cannot force yourself to be lactose tolerant Bacteria CANNOT acquire resistance to antibiotics New traits cannot be created during your lifetime Only genes can be passed on
Darwin’s Finches Biogeography- geographic distribution of life forms Galapagos Islands- Volcanic islands off the coast of South America Species were slightly different than the ones on the mainland Finches- different beaks depending on the food available Cactus eating finch-more point beak Insect eating finch- sharp ( trees) Types of seeds All descended from one mainland Finch DESCENT WITH MODIFICATION from a COMMON ANCESTOR
Blue Footed Boobie
Natural Selection Mechanism for evolutionary change 1. Inherited variations: Mutations- changes in DNA Meiosis 2. Not all individuals survive 3. Adaptations( traits that help an organism be more suited to the environment ) increase survival and reproductive success ( Fitness - reproductive success) 4. Genes for adaptations increase in each generation
The result of Natural Selection is a population adapted to the local environment
Anatomical Evidence a. Homologous Structure: Structures that are similar because they are inherited from a common ancestor
Anatomical Evidence b. Analogous Structures: features are similar in function but not in structure. They do not derive from a recent common ancestor but in response to a similar environment.
Anatomical Evidence C. Vestigial structures: no longer have function. occur because organism inherit anatomy from their ancestors. Ex. Some snakes have small hindlimbs Humans: Appendix, wisdom teeth, tail bone
THEAPPENDIX VESTIGIAL STRUCTURE
Biochemical Living organisms use DNA, and many identical enzymes (same 20 amino acids) Degree of similarity of DNA sequence or amino acid structure based on how closely related
Embryos of closely related organisms often have similar stages in development.
Causes of Microevolution 1. Mutations are the raw material for evolutionary change 2. Gene Flow- 3. Non random mating 4. Genetic Drift