Download Evolution - Ms. M`s Biology Class

Natural selection and adaptation quiz: You need a
sheet of notebook paper numbered 1-7.
 Get out your homework! (If you did
not complete it)
(Adaptations & Natural Selection)

 Catalyst: Quiz (10 minutes)
 Evolution and Speciation (15 minutes)
 Speciation Practice/Trashketball
(Remaining)


Mastery grades
DM: Tally Dojo points
What determines which organisms survive
and which do not?
 Do species ever change?
 How do scientists believe all of the species
that exist today were formed?
 What evidence is there to support
evolution?

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SPI 3210.5.3 Recognize the relationships among
environmental change, genetic variation, natural
selection, and the emergence of a new species.

SWBAT define species, speciation and identify
factors that result in speciation
SWBAT distinguish between convergent and
divergent evolution

Biology
Unit 3
Section 15.2

Review: What is evolution?
 Evolution is the gradual change in a
population of organisms over time
▪ The key is over a long period of time

What is one of the main ways evolution
occurs?
 One of the main ways evolution occurs is
through natural selection
 Who developed this concept?

Examples of natural selection:
 Peppered moths
 Antibiotic-resistant bacteria
 Green/brown lizards
We are going to
be talking about
Different theories.
They may conflict
with your beliefs
(and that’s okay).
Its something that
we need to cover
in order to
prepare you in
Biology.


From where do scientists suggest that all
organisms that exist today came?
Key Point 1: Many scientists believe that all
species that exist today evolved from a
common ancestor
 What is an ancestor?

Even humans?
 Even humans!
▪ From primates (chimpanzees)

Natural selection causes a population to
evolve, but it may or may not create a new
species
 Deer mice: dark brown  light brown mice
 Moths: Light moths  dark moths
▪ These examples of evolution did not create a
new species, however
REVIEW:
Key Term: A species is a group of organisms
that can mate and produce fertile offspring
 Fertile offspring means the offspring are also
able to reproduce


If a population of organisms adapts to its
environment and can no longer reproduce
with other populations, a new species has
evolved.
Key Point 2: Speciation is the development
of a new species of organisms from an
existing species
 This typically occurs over a very long period of
time

Key Point 3: Speciation can be caused by:
 Geographic isolation—a population is
separated by a physical barrier
▪ May be separated by a mountain, canyon,
river, etc. or because of flooding or other
changes in habitat
▪ Organisms no longer mate and are forced to
develop different adaptations to survive
▪ Eventually they cannot reproduce together

Reproductive isolation

Populations no longer mate or produce
fertile offspring due to different mating
seasons, different anatomies, or different
number of chromosomes in their gametes


Two populations of toads began mating
during different times of the year and no
longer reproduce. Over time, two different
species of toads have developed.
Is this a result of geographic or reproductive
isolation?


A flood forces one population of snakes to
move to another habitat. Over time, this
population evolves into a new species of
snake as it adapts to its environment.
Is this a result of geographic or reproductive
isolation?


Two different species of mountain goats have
appeared on opposite sides of the Rocky
Mountains.
Is this a result of geographic or reproductive
isolation?
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Key Point 4: When one species evolves into
two or more different species, this is
known as divergent evolution
Example: Scientists believe that various
species of cats (cheetahs, leopards, jaguars,
etc.) evolved from a common ancestral
species many years ago
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Key Point 5: When different species change
over time to become more similar due to
similar environments this is known as
convergent evolution
Example: Sharks and dolphins are different
species, but over time they have developed
similar adaptations to survive in their
environments
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
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Each species of mammal below is believed to
have evolved from a common ancestral
species
Convergent or divergent evolution?
Why?

The thorny devil and Texas horned lizard are
two different species of lizards that have
adapted over time to eat similar foods and
behave in similar ways because of similar
environments

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Convergent or divergent evolution?
Why?
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These two tortoises above belong to different
species. Scientists believe they evolved from
a common ancestor but developed different
adaptations to survive in their environments.
Convergent or divergent evolution?
9.
What is the term used to describe the
development of a new species from an
existing species?
Speciation
10.
What term is used to describe a group of
organisms that can reproduce and produce
fertile offspring?
Species
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Speciation Trashketball
I will give you a certain amount of time to
answer each question. When it is your team’s
turn, I will randomly call on someone to
answer.
Get it right = take a shot