Download Lamarck said Organisms acquire or lose certain traits during their

UNIT 9 NOTESCLASS SET
EVOLUTION NOTES
PLEASE RETURN THIS TO ME.
Chapters 15, 16, and 17
ADAPTATION IS an inherited characteristic that
increases an organisms chance of survival.
What is the theory of
acquired traits?
Theory of acquired traits: Lamarck said
Organisms acquire or lose certain traits during their
lifetime by use or disuse.
These traits could then be passed on to offspring.
Over time this would cause change in a species
Example: The giraffe’s neck growing longer to reach
the food on taller trees.
Who is Charles Darwin and Traveled around the world on the HMS Beagle and
what did he do?
made many important observations on the Galapagos
Islands. He developed the theory of natural
selection and published The Origin of Species
What is evolution?
Evolution: is change in a population over time. As
the environment changes, species either adapt or go
extinct.
Populations Evolve, Individuals Do Not!!!!
Explain Natural Selection. Population: Members of the same species who can
reproduce a fertile offspring.
Variation: Different traits within the population
leads to different phenotypes. Some variations are
better for the current environment conditions.
Survival of the Fittest: Those adapted to the
environment can survive and pass genes to the next
generation and those who can’t adapt will die or
leave fewer offspring.
Natural selection: Species change over time because
of changes in the environment.
Example: Species compete for food, space, and
mates.
UNIT 9 NOTESCLASS SET
How does microevolution
occur?
Microevolution are small
changes between
generations.
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Mutation: Allele is changed randomly
Mutation present in offspring and may be passed to
next generation
Migration: New individuals leave to settle into a
population.
Genetic drift: By random chance, individuals mate
and increase allele frequency.
Natural selection: Survival of the fittest… When
traits make organisms better able to survive an
environment.
What evidence do we have Fossil record: are the remains of ancient life.
for macroevolution?
Older fossils are in the layers towards the bottom.
Biochemistry/Molecular Biology: Organisms share
many of the same biochemical details.
(The genetic code for protein-coding genes Amino
acid sequences.)
Homologous structures: Same Structures; Different
Functions. Whales and Humans have the same
arm/hand bone structure, but use them differently.
Analogous structures: Different Structures; Same
Function. Birds and Butterflies have wings but the
wings have different structures.
Vestigial structures: Traces of structures no longer
used by organism.
Comparative embryology: Embryos of many animals
with backbones look so similar they are hard to tell
apart.
UNIT 9 NOTESCLASS SET
What is speciation and
how does it happen?
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Speciation: Changes leading to formation of new
species.
Populations evolve and become reproductively
isolated from each other (members of two
populations cannot interbreed)
-Behavioral isolation: Capable of interbreeding, but
have different courtship rituals.
What are some patterns
of evolution?
-Geographical isolation: Populations separated by
geographic barriers (rivers, mountains, bodies of
water, etc.)
Adaptive radiation: Small group of species evolve into
different forms they have to live in different ways.
Convergent evolution: Unrelated organisms begin to
resemble each other.
Similar environmental demands
Coevolution: Two species evolve in response to
changes in each other.
Ex. A humming bird evolves with a longer beak or
tongue as the flower’s tube grows longer over time.