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By: Mr. Godinez
• Evolution: process by which modern organisms have
descended from ancient organisms, by change over
time
GRAVITY
• Theory: is a well-supported testable explanation
of phenomena that have occurred in the natural
world
• Species: a group of
individuals that can
potentially interbreed
• Species Population: a
discrete group of
potentially interbreeding
organisms in the same
species in a given locality
Evolution by Natural Selection
• Struggle for existence: members of each species
compete regularly to obtain food, living space, and
other necessities of life.
• Fitness: ability of an individual to survive and
reproduce in its specific environment
• Adaptation: any inherited characteristic that increase
an organism change of survival
• Survival of the fittest: individuals that are better
suited for their environment-with adaptations that
enable fitness-survive and reproduce most
successfully.
• Natural selection: results in the changes in the
inherited characterits of a population. These changes
increase a species fitness in its environment.
Historic Context
•1785-James Hutton
• Estimates earth to be millions of years old-Earth is OLD
•1798-Thomas Malthus
• Principles of Population-idea that earth cannot support a
lot of humans- Limited Resources  Competition
•1809-Jean-Baptiste Lamarck
• Inheritance of acquired traits-mechanism for how
organisms change- Allowed for Idea to be Challenged
Historic Context
•1831-Charles Darwin
• Voyage on Beagle-gathers evidence leading to his theory
of evolution- Observation of species diversity/variation
•1858-Alfred Wallace
• Comes to a similar discovery of evolution through
natural selection- Competition to publish theory First
•1959-Charles Darwin
• Published the Origin of Species
Lamarck’s Evolution Hypothesis
• Lamarck proposed that
• By selective use or disuse of organs, organisms
acquired or lost certain traits during their lifetime.
• Traits could then be passed on to their offspring.
• Over time, this process led to change in a species
Darwin’s Evolution Hypothesis
• Darwin proposed that
• Environment selects for traits, that would result in
the survival of organisms
• Organisms acquired or lost certain traits through
generations.
• Traits could then be passed on to their offspring.
• Over time, this process led to change in a species
Defining Evolution
Evolution is a consequence of the interaction of four factors:
1. The potential for a species to increase in number
2. The genetic variation of individuals in a species due to
mutation and sexual reproduction
3. Competition for an environment’s limited supply of the
resources that individuals need in order to survive and
reproduce
4. The resulting proliferation of those organisms that are
better able to survive and reproduce in that environment.
Artificial Selection
• Artificial selection: nature provided that variation, and
humans selected those variations that they found
useful.
• Led to domestication of animals and crops(plants)
• Descent with modification: species today look different from
ancestors. Each living species had descended, with changes, from
other species over time.
• Common descent, all species-living and extinct-were derived from
common acnetors.