Chapters 14 and 15
What is science? Study of the natural world Systematic study through observation and experimentation.
What is a scientific theory? a well-supported testable explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiments.
Charles Darwin February 12,1809 April 19,1882 Naturalist Deeply Religious Studied intensely fossils and organisms from his trip
Educational Background Undergraduate degree in Theology from Christ s College, Cambridge. Had previously studied medicine Had read and studied intensely Lyell s Principles of Geology Had studied Malthus Essay on the Principles of Populations.
Voyage of the HMS Beagle 1831-1836
After Darwin s Trip Darwin kept meticulous notes during his trip. Collected many fossils and live specimens which he took back to England. He along with many others analyzed and classified the never before seen species.
Darwin s Finches Gould determined that the Galapagos finches were separated species The finches did not live anywhere else in South America. The island finches resembled the mainland finches although the island and mainland were different environments The lead to Darwin to hypothesize...
New species could occur gradually through small changes in ancestral species Using Malthus work as a building block Darwin hypothesized the theory of Natural Selection- Some competitors in the struggle for existence would be better equipped for survival than others.
On the Origin of Species Darwin compiled his research and proposed his theory. Alfred Wallace had proposed a theory almost identical to Darwin s. Both presented to the Linnean society of London. Darwin published first.
Theory of Natural Selection 4 basic principles 1) Variation in individuals in a population 2) Variations are inherited 3) Organisms usually produce more offspring than can survive on available resources. 4) Inherited variations that increase reproductive success will eventually become predominate in a population.
Things to Understand Scientifically, evolution is the cumulative changes in groups of organisms through time! Natural Selection does not mean the same thing as evolution! Natural Selection is the process by which evolution (change over time) occurs!
Populations evolve- Organisms do not Overtime, natural selection can modify a population to produce a new species. (pg. 421 in text book) 2 exceptions...
Fossil Record Provides evidence of species that lived long ago. Shows how ancient species are similar to current ones and how some species have remained unchanged for millions of years.
Trilobite Ancient Lizard
Archaeopteryx Transitional Species
Comparative Anatomy
Homologous Structures Homologous- having the same or similar structure Anatomically similar structures inherited from a common ancestor.
Analogous Structures Structures that look similar but are not inherited from a common ancestor
Vestigial Structures Vestigial- being trace; no longer functional Structures that are the reduced forms of functional structures in other organisms.
Comparative Embryology
In their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.
Similar animals in different locations were the product of different lines of descent. Geographic Distribution
Comparative Biochemistry Molecules in species with a recent common ancestor should share certain ancient amino acid sequences. Similar biochemical patterns in DNA or in amino acid sequences (proteins)
Adaptation Lies at the heart of the theory. Camouflage: morphological adaptations that allow species to blend in to their environment Mimicry: a species evolves to resemble another species.