Download Intro to Evolution

HAPPY THURSDAY
Journals out!
Bellwork (left side): Quickwrite –
in 43 words explain why this would be happening?
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.
Turn in Family Tree Projects in the back of the room. Due today for up to a
70. Make sure name, date and period number are clearly written on them.
Due Dates
• Natural Selection Video guide: Due today
• Family Tree: today for a 70, tomorrow for a 50
• Notecards: due Monday (word, definition,
picture)
Journals out, you diploids!
Page:_____
Title: Intro to Evolution
EQ: How do natural selection and
adaptations work to increase
diversity within a species?
B.7C - Analyze and evaluate how natural
selection produces change in populations, not
individuals.
B.7E - Analyze and evaluate the relationship of
natural selection to adaptation and to the
development of diversity in and among species.
What is
Evolution?
Evolution: change in the traits of a population
over time
Evolution is “the grand unifying theory of biology.”
Evolutionary theory continues to change as new data
are gathered and new ways of thinking arise.
Gene pool: 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.
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
Darwin published the results of his work in a
book called On the Origin of Species.
Mechanisms of Evolution
(How does evolution happen?)
There are 5 factors that can cause
evolution to happen and 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:
• DNA 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 not
selected at random. They are
chosen for specific
characteristics..
•This limits the size of the gene
pool because only the genes of
the mating individuals are
passed to the next generation.
3. Natural selection:
individuals with characteristics not well suited to
their environment either die or leave few offspring.
It is not seen directly, but only observed as changes
in a population over a long time.
3. Natural Selection
• advantageous genes are passed on to the next
generation while harmful or unfavorable genes
are eliminated from the gene pool
• survival of the fittest
*the driving force of evolution
Examples of natural selection
Why does natural selection happen?
1. Environmental resources:
limits the size of populations
2. Fitness: the ability of an organism
to survive and reproduce.
3. 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.
Closure: True or False?
T
1. Natural selection is one of several
evolutionary processes
T 2. Species living today continue to evolve
F 3. Individual organisms can evolve
T 4. Evolution can occur rapidly
T 5. Species can choose to evolve what they need
to survive through natural selection
F 6. Evolution is a process that makes organisms
perfectly adapted to their environments
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.