Download Intro to Evolution with HOMEWORK

 HAPPY TUESDAY 
Bellwork: Write down only the bolded red portion and
your answer.
Two species of mice live in a field in the middle of East
Texas. One mouse species is WHITE with BLACK
spotting. The other is BROWN with WHITE
spotting.After a year, the population of white mice has
dramatically decreased, while the population of the
brown mice has slightly increased. Why would this be
happening?
Please also have a pen or pencil and
your journal or paper ready. 
Standard: (7E)Analyze and
evaluate relationship of natural
selection to adaptation.
Essential Question: How does
evolution happen?
What is
Evolution?
Evolution: change in heritable traits of a
population across generations (over
time).
Evolution is called “the grand unifying theory of biology.”
Evolutionary theory continues to change as new data are
gathered and new ways of thinking arise.
A gene pool is the total number of genes of
every individual in an interbreeding
population.
Evolution can also be defined as a
change in the gene pool over time.
What important contribution did
Charles Darwin make to biology?
Charles Darwin: contributed more to our understanding
of evolution than anyone else.
• Darwin traveled, made observations and collected evidence that
led him to propose his revolutionary process in a book called Origin of
the Species.
Mechanisms of Evolution
(How does evolution happen?)
There are 5 factors that can affect the
frequency of a gene in the gene pool.
1.
2.
3.
4.
5.
Genetic Mutation
Non-random mating
Natural Selection
Small Population
Gene Flow
1. Genetic Mutation:
• Changes in DNA that happen due to errors in
replication, transcription, translation, or
because of environmental factors.
– The source of all new genes/traits in a population
• If mutations are passed on to offspring (over
generations), then evolution has occurred
2. Non-Random Mating
• Not all mates are created
equal.
• In many species, mates are
chosen for specific
characteristics. Many
organisms compete for mating rites.
Strong and good-looking organisms
are typically favored.
• This limits the size of the
gene pool
3. Natural Selection
• survival of the fittest
• advantageous genes are
passed on to the next
generation while harmful
genes are eliminated
• the driving force of evolution
Examples of natural selection
Why does natural selection happen?
Population size is
limited by
environmental
resources
Fitness: the ability of an organism to survive and
reproduce.
•
Fitness is the result of adaptations.
Adaptation: any inherited characteristic that
increases an organism’s chance of survival.
Successful adaptations:
- enable organisms to become better suited to
their environment
- increase an individual’s ability to survive and
reproduce.
Humans have thousands of adaptations: large brain,
opposable thumbs, excellent sensory organs, light,
strong skeleton, etc.
Bunny Simulation
If only one species is considered the "fittest", why do we still have so many
variations among species. Why do some birds have very long pointy beaks,
while other birds have short flat beaks?
Debrief Options
• Create a chart on the bunny simulation
• What are adaptations that can help the wolf
survive?
• Quickwrite answering Essential Question.
Homework: Watch “Natural Selection”
by Stated Clearly
• Write a 3 sentence summary of the concept of
natural selection
• Write a 3 sentence opinion of the concept of
natural selection
• Give one example of natural selection
Summary of Darwin’s Theory:
 Individual organisms differ and some of these variations are
heritable (passed on)
 Organisms produce more offspring than can survive and
many that do survive do not reproduce
 Because more organisms are produce than can survive, they
must compete for limited resources (food, shelter, etc)
 Each unique organism has different advantages (good) and
disadvantages (bad)
 Individuals best suited to their environment survive and
reproduce successfully
 These organisms that survive pass their heritable traits to
their offspring
Summary of Darwin’s Theory cont’d:
 Other individuals that are not suited for their
environment die or leave few offspring
 This process called natural selection causes species
to change over time
 Species alive today are descended with modification
from ancestral species (their ancestors)
 This process by which diverse species evolved from
a common ancestor unites all organisms on Earth
into a single tree of life
What to do:
1. Check you grade in the
back.
2. Figure out which of the
assignments you need to
make up.
3. Get the assignment.
4. When finished, turn it in to
you class period tray.
Basic Characteristics of Mars:
• Diverse terrain, including: mountains,
valleys, polar ice caps, deserts
• Atmosphere has clouds, thus rain
• The red color is due to blowing sand
• Has vegatation
• It is VERY cold.
IF YOU HAVE NOTHING TO MAKE UP:
• Congratulations! You won a trip
to space! You are going to Mars
to study the organisms that live
there. When you arrive you
observe 2 new species. Using the
basic characteristics of Mars,
create the two species you
encounter with adaptations that
are appropriate for life on Mars.
Write 5 sentences describing the
organisms and draw a picture of
them on Mars.