Evolution
Theory
• Well supported testable explanation of
phenomena that have occurred in the natural
world
Biosphere
• Part of earth in which life exists
– EX: Land, water, air
Evolution
• A change over time
• Most often used to refer to a change in a
species over time
• EX: Dinosaurs change into birds
Charles Darwin
• One of the first scientist to publish his ideas
about evolution in The Origin of Species
• He developed his theory of evolution from
observations he had made during his world
travels
Charles Darwin (cont.)
• Darwin traveled around the world on a ship
called the HMS Beagle
• He observed a wide variety of organisms, and
noted characteristics that occur in similar
species of plants and animals
Galapagos Island
• In five years of traveling on the HMS Beagle,
the Galapagos Islands proved to be the most
influential on Darwin’s ideas about evolution
Galapagos Finches
• Although the islands were close together, each
island had its own distinct animal and plant
populations
– EX: Galapagos Finches – They had different beaks
suited to the different foods they consumed
Natural Selection
• States that organisms with favorable traits
are more likely to survive, reproduce, and
pass those traits onto their offspring
Survival of the Fittest
• Also known as Natural Selection
Fitness
• An organism’s reproductive success
• Organisms with greater fitness reproduce and
pass on their traits to their offspring
Adaptation
• The process by which a population becomes
better suited to its environment which
increases chances of survival
– EX: Peppered moth AND giraffes with long necks
Mutation
• A change in DNA. This is the only way of
introducing a new trait to a species
Recombination
• Genes are rearranged during meiosis to
create unique offspring and the species is
more likely to survive a catastrophe, such as
a disease
– EX: Crossing over
Evidence of
Evolution
Fossil Record
• Older remains or fossils always lie beneath
the newer remains or fossils
• This allows us to determine the age of a fossil
in relation to the other fossils
Homologous Structure
• Similar structure BUT different function
• Evolve from a common ancestor
– EX: Whale fins and human arms
Analogous Structure
• Different structures BUT same function
• Share a similar environment
– EX: Butterfly wing and bird wing
Vestigial Structure
• Structures in species that serve no function
– EX: Leg and hip bones in whales AND appendix in
humans
Embryology
• Study of similarities between organisms
during early stages of development
– EX: Humans and fish both have gills in early
development
Artificial Selection
• Selection by humans for breeding of useful
traits
– EX: Pure breed dogs AND artificial crops