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7/30/2019 Chapter 11 - Lessons 1,2,3
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Chapter 11
Lesson 1 Evidence of Evolution What is evolution? Evolution is change over time.
The scientific theory of evolution explains howliving things descend from earlier organisms.
It helps us understand the history of life on Earth.
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What evidence supports evolution?
Fossils Similarities on DNA and protein structure
Similarities of body structure
Similarities in Early Development
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Fossils Fossils help scientist infer about the shape and
function of ancient organisms' body structures.
They support the theory that living organisms
evolved from earlier simpler organisms.
The Fossil Record (the millions of fossils collected
by scientists and organized by date) gives clues of
how and when a new species evolved and how
organisms may be related
Species a group of similar organisms that can mate
with each other and reproduce fertile offspring.
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Similarities in DNA and protein
Structure Scientists infer that species inherited many of
the same genes from a common ancestor.
The more similar the DNA sequence the moreclosely related the species are.
The order of amino acids in proteins can also
show how closely related two species may be.
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Similarities in Body Structures Organisms that share the same basic body
plan are assumed to have come from acommon ancestor.
Vertebrates have a backbone.
Invertebrates do not have a backbone.
Homologous structures structures shared by species are attributed to a
common ancestor.
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Similarities in early Development
Scientist also infer evolutionary relationshipsby comparing early development of organisms.
Organisms with common ancestry look similar
during the early stages of development.
(See next slide.)
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Lesson 2 Darwins Theory
Discovery Streaming
Natural Selection
The world of birds Eating like a bird
Gizmo Activities
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What is Natural Selection? Natural selection is the PROCESS by which
individuals that are better adapted to theenvironment are more likely to survive and
reproduce than other members of the same
specie. Adaptation - trait that increases the organisms
ability to survive and reproduce.
Variation - differences between individuals of
the same species.
Trait genetic characteristic.
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Environmental change + Adaptation = Natural
Selection.
The case of the Moth during the industrial
revolution.
The case of antibiotic resistant bacteria and super
bugs.
White Lizard
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Lesson 3 Biodiversity and
Extinction
How do new species form?
A new species can form when a group of
individuals remain isolated from the rest of its
species long enough to evolve different traitsthat prevent reproduction.
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What factors affect biodiversity? Biodiversity the number of different species in an area.
Factors that affect biodiversity in an ecosystem are as
follows:
Area the larger the area the more biodiversity.
Climate tropical rainforests are the most diverse
ecosystems.
Genetic Diversity species with diverse gene pools are
better able to adapt and survive. changes in theenvironment.
Niche Diversity a diverse habitat supports a larger
number of species than a uniformed habitat.
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Why do species go extinct?
Extinction when all members of a species
disappear on Earth.
Process of extinction Threaten species in danger to become endangered.
Endangered species in danger to become extinct.
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Extinction and Human Activities Extinction is a natural process that usually
happens gradually.
Extinction rates have increased do to human
activities.
Pollution
Contamination
Destruction of habitats Invasive species
Hunting
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