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EVOLUTIONARY THEORY
Scientific theory
• THEORY= a well tested explanation
that makes sense of a great variety of
scientific observations.
– Only become widely accepted when
they are supported by LOTS of evidence
What is Evolution? • EVOLUTION – process of
biological change
– Descendants differ from their ancestors
– Change in genetics of a species
• ADAPTATION – inherited characteristic that improves an organisms ability to survive and reproduce – Can be physical or behavioral
The Mantis Shrimp is my New Favorite Animal
So who thought of Evolution?
• BUFFON - Earth is much older than
previously thought, some fossils look
similar to living organisms
• LYELL- gradual changes in earth from
physical processes, EARTH IS OLD
Malthus
• Malthus- in 1798 he published Essay on the Principles of Population. – This piece explained that every 25 years
the human population will double unless limited by food supply.
• Organisms will overproduce but will then need to compete for resources
Lamarck
• Use it or lose it
• “Inheritance of acquired traits“
• A change in the environment causes
changes in the needs of organisms
living in that environment, which in turn
causes changes in their behavior.
• Giraffe, muscles, etc.
Darwin
• Proposed the idea of natural selection
Who is Charles Darwin?
• February 12th, 1809 – April
19th,1882
• English naturalist
• Studied the diversity of life
and proposed a broad
explanation of it.
Who was Charles Darwin?
Darwin Continued
• Modern evolutionary theory began
when Darwin presented evidence that
evolution happens and offered an
explanation of how evolution
happens.
GOOD MORNING!!!
Happy Tuesday! This morning we are going to be enjoying some Virtual Reality in the Galapagos! But
before that… we got some stuff to do!
Please do the following to prepare for class: • Get out a notes sheet ready to finish our
evolutionary theory notes
• Grab one of the packets off the front table (we won’t need these until later)
Darwin’s Ideas
• During this time period
people did not think
that living things had
changed over time.
– But Darwin saw
evidence of gradual
change.
• His first evidence was
gathered during his
global voyage aboard
the Beagle.
Darwin’s Travel
• Darwin also visited the Galapagos Islands in the Pacific Ocean. – Island contain
several different finches, which were all very similar.
– The size and shape of the bill (beak) varied.
– Each bill was specialized for a certain purpose.
• Important characteristics: each island
had unique/different organisms but all
were related to mainland organisms
• DARWIN INFERRED… mainland species
had changed after they colonized the
islands & adapted to their new
environments
HAPPY MONDAY!
Only 4 days until Spring Break!!
Today we will be looking a little deeper into evolutionary theory.
To prepare for class today, please do the following: • Get out your warm up page
• Have your Evolution vocab out and ready to be checked.
• Have a notes sheet out and ready (if you didn’t use up space on your last one… save some paper and use it up)
FOR TODAY’S WARM UP…
Please make the following table for your
warm up:
LAMARK DARWIN
HOW WOULD LAMARK & DARWIN EXPLAIN THESE TRAITS?
Owls are known as silent predators of
the night, capable of flying just inches
from their prey without being detected.
The quietness of their flight is owed to
their specialized feathers.
First, the leading edge of the owl’s wing
has feathers covered in small structures
that project out from the wing. These
serrations break up the flowing air into
smaller flows that are more stable along
the wing. Furthermore, this change in
airflow patterns also appears to reduce
the noise of the flowing air. The
wing’s serrated leading edge appears
to be most effective at reducing noise
when the wing is at a steep angle—
which would happen when the owl is
close to its prey and coming in for a
strike.
https://www.youtube.com/watch?time_continue=15&v=a68fIQzaDBY
After the Voyage of the Beagle
• Darwin returned to England to analyze his data and observations
• Published “The Origin of Species: by means of Natural Selection” – 200 pg essay in 1859
• 2 Main Points – Descent with Modification
– Natural Selection
Descent with Modification
• Species today came from ancestral
organisms
– Descendants spread out over different
habitats and environments
– Accumulated adaptations to new
environments
• Explains diversity of life on Earth
Evolution by Natural Selection
• Individuals that have traits that better suit their environment are more likely to survive.
• Darwin’s theory predicts that over time, the number of individuals that carry advantageous traits increase in a population.
Inherited shell variations make some snails less likely than others to be attacked by predators.
Wide, blunt shells increase the chances for snails to survive and pass their traits to the next generation by reproducing.
EVIDENCE FOR EVOLUTION
Fossils
• Comparing fossils can reveal
a pattern of gradual
change.
• Shows vestigial structures.
Anatomy
• Many internal similarities are best explained by
evolution.
• Homologous Structures- a characteristic that are
shared by a group of species because it is
inherited from a common ancestor.
Anatomy (Continued)
• Analogous structures – do not show evolutionary origin – Similar environment led to similar
structures and functions
• Vestigial structures – structure that has lost all or most of it’s function – Tail bone
– Appendix
Biogeography
• Darwin found that all around the world
similar animals lived in similar environments.
Developmental Biology
• Scientists compare
embryonic
development of
many animals
– They find similarities
and patterns
– Example: all
vertebrates have
tails!
Biochemistry
• Remember genes control the physical
appearance of animals, so DNA plays
a huge role in Natural Selection.
• Studying DNA can show how similar a
species is…or how different.
GOOD MORNING!
Two more days until Spring Break!!!
Today we are going to get you guys ready for
your Quarterly Exam!!!
Please do the following to prepare for class:
• Grab one of the sheets off the front table
• Have something out to write with
HELLO HELLO HELLO!!! Only ONE more day until Spring Break! We are
so close! Today we will be reviewing for your
Quarterly… but first…. VOCAB QUIZ!
Please do the following to prepare for class:
• Look over your Evolution Vocab Packet
• Have something out to write with
When you are finished…
1. Make sure your name is on it!!!!
2. Bring them up to me so I can start
grading
3. Wait quietly for everyone to finish
- ABSOLUTELY NO CELL PHONES! I SEE IT. I
TAKE IT. YOU GO TO SARS AND GET A ZERO.
KABOOM REVIEW GAME
WE WILL BE PLAYING 15 MINUTE ROUNDS TWO TIMES
Please be careful of the cards!
NATURAL SELECTION
ONLINE SIMULATION
JUST SO YOU CAN BETTER UNDERSTAND IT
GOOD MORNING PEEPS
It is a beautiful out today! Make sure you spend time enjoying it. But hope you’re brain is thinking
everything biology because today is your Quarterly Exam.
To prepare for class, please do the following:
• Take a few minutes to look back over your study guide
• Have something to write with
• Take a few deep breaths… you got this!
WHEN YOU ARE FINISHED…
1. Make sure your name AND test book number are on your answer sheet!
2. Place your test book and answer sheets on the front table.
3. Grab the worksheet on the front table
4. Grab your ASSIGNED chromebook number from the cart and return to your seat – Go to www.sciencewithhamory.weebly.com
• Go to course information; materials & documents; 4th marking period
• Find “The Beak of a Finch” video • Watch and answer pre-lab questions (you may use
headphones) • Once finished, please wait for the rest of the class!
Hola amigos! I hope you all had a wonderful weekend! Today we are going to be moving forward in evolution but of
course we will start with a review of what we learned so far.
To prepare for class, please do the following:
• Grab a notes sheet (or paper of your choice) and have something out ready to write with for notes in a hot sec.
• Grab your assigned chromebook number
• Go to www.kahoot.it
MODES OF SELECTION
Let’s Talk a Little More About This
Natural Selection thing…. Natural Selection: individuals with traits well suited for an
environment will leave more offspring than individuals
lacking the desired traits.
• This repeats over time, each new generation has a
higher proportion of individuals with this advantageous
trait.
• Could cause isolated populations to become separate
species as they adapt to new environments.
• Nature selects, not humans.
Beetles with brown genes escaped predation and survived to
reproduce more frequently than beetles with green genes, so
that more brown genes got into the next generation.
• Darwin proposed that natural selection is
the cause of evolution.
• This theory can be summarized in 4 steps:
– Overproduction- more offspring created than
can survive. Not all individuals will survive.
– Variation- exists within every population (inherited traits)
– Selection- Certain traits make individuals
more or less likely to survive and reproduce.
– Adaptation- OVER TIME, those traits that
improve survival will become more common.
Sexual Selection
• Mode of natural selection in which
some individuals out-reproduce others
of a population because they are
better at competing for mates
Click on us to
see how it
happens!
Natural Selection CER
CER Writing
• A CER (Claim, Evidence, Reasoning) is a format for writing about science. It allows you to think about your data in an organized, thorough manner. See below for a sample and the grading rubric.
• Claim: a conclusion about a problem
• Evidence: scientific data that is appropriate and sufficient to support the claim
• Reasoning: a justification that shows why the data counts as evidence to support the claim and includes appropriate scientific principles
GOOD MORNING BEAUTIFUL
PEOPLE! It’s Friday Eve! So our week is almost over! Today we are going to be looking at the genetic aspects of evolution.
To prepare for class, please do the following:
• Place your Which Beak is Better? Lab and extended research (attach them together) in the turn in bin
• Get out a section of paper for your warm ups
• Get out a notes page (or paper you would prefer to use)
• Have something to write with
WARM UP Match each image below with the correct factor of natural selection
Overproduction Variation Selection Adaptation
A. B.
C. D.
Speciation
• BOTH natural selection & sexual
selection cause the genetic
characteristics of a species to change
which sometimes leads to the
formation of a species which is known
as speciation.
Artificial Selection • Selective breeding of plants and animals to produce offspring
with genetic traits that humans value
• Breeder role of environment
• EXAMPLES: – PLANTS- bred for production, disease resistance, protein content – ANIMALS- growth rate, milk production, temperament
https://www.youtube.com/watch?v=F-XTUpLmhPc
Natural vs. Artificial Selection
NATURAL
SELECTION
ARTIFICIAL
SELECTION
Nature selects
the traits (based
on environment)
Humans select
the traits
Leads to
ADAPTATION
MICROEVOLUTION
Microevolution
• Refers to evolution as a change in the
genes of population
• To study microevolution, we must look
at the processes that change inherited
traits.
– 5 majors processes- natural selection,
migration, mate choice, mutation, and
genetic drift.
Natural Selection
• Can cause an
increase or
decrease in
certain alleles in
a population.
Migration
• Migration is the movement of
individuals into, out of, or between
populations.
• Can change the numbers and types of
alleles in a population.
Mate Choice
• If mating is totally
random, then
offspring will gain
random traits.
• If mating is
selective/limited
then the choice of
specific traits will be
passed down.
Mutation
• Mutations can
change the
numbers and types
of alleles from one
generation to the
next.
Genetic Drift
• Genetic make up changes based on
random chance events.
• Survival may be totally unrelated to
genotype
• Ex: Bottleneck and Founder Effect
Let’s Take a Further Look at
Microevolution
Changes in A Gene Pool
Worksheet
Well hello there strangers….
So I’m sick but that’s okay because ya know what…. It’s Movie Monday!
To prepare for class, please do the following:
• Have a piece of paper for notes (sorry, y’all I’m out of notes sheets)
• Have something to write with
• Grab one of the worksheets off the front table
MACROEVOLUTION
Macroevolution
• Refers to the appearance of new species
over time.
• To study macroevolution we look at the
patterns in which new species evolve.
• Patterns of change are seen when
relationships between living and fossil
species are modeled.
– Convergent evolution, coevolution, adaptive
radiation, extinction, gradualism, and
punctuated equilibrium.
Convergent Evolution
• If evolution is directed by the environment then similar environments should evolve similar adaptations.
• Two distinct species with differing ancestries evolve to display similar physical features
Reptile Mammal Fish
Coevolution
• Organisms live in the environment with other
organisms. Sometimes they affect another’s
evolution.
• Adaptations may evolve to survive with other
organisms.
How to Grow a Planet; The
Power of Flowers
YAY MOVIE TIME!
Adaptive Radiation
• Over time, species may split into two or
more lineages.
• Occurs rapidly when a new species
enters a more desolate location.
Gradualism
• Many think that new organisms
arise/evolve through very small and
slow steps.
Punctuated Equilibrium
• Opposite of gradualism
• Species are stable for a long period of
time, then environmental changes
cause a rapid/sudden evolution of
new organism.
Extinction
• If all members of a lineage die off or
fail to reproduce, this species is known
as extinct.
• Most animals have gone extinct, only
a small percentage are around today.
TAXONOMY, PHYLOGENY, &
CLADISTICS
AKA CLASSIFICATION
Overview • Phylogeny is the evolutionary history of a
species or group of related species usually
organized into a phylogenetic tree
• Phylogenetic trees and cladograms (also
tree shaped) seek to arrange organisms
based on common ancestry
Phylogenetic Trees
• Keep in mind phylogenetic trees and
cladograms represent a hypothesis
about evolutionary relationships and
are ever-changing based on new
evidence
Tree Structure • Each branch point
represents the divergence of two species
• Sister taxa are groups that share an immediate common ancestor
• A rooted tree includes a branch to represent the last common ancestor of all taxa in the tree
• A polytomy is a branch from which more than two groups emerge
What we CAN & CANNOT
Learn…
• Phylogenetic trees DO show patterns of descent
• Phylogenetic trees DO NOT indicate when species evolved or how much genetic change occurred in a lineage
• It shouldn’t be assumed that a taxon evolved from the taxon next to it
What is the difference between a
phylogenetic tree and a cladogram?
• Many biologists use these terms interchangeably
• Both are based on ancestral relationships
• In phylogenetic trees branch lengths can represent the amount of genetic change or are proportional to time
• In cladograms the branch lengths are usually considered to be arbitrary
How To Read A Cladogram • These relatives share a common ancestor at the root of the
tree.
• Note that this diagram is also a timeline. The older organism is at the bottom of the tree.
• Branches on the tree represent speciation
• The event that caused speciation is shown as a fork on the tree.
How To Read A Cladogram
• A CLADE places species into groups that includes an ancestral species and all of its descendants.
• If you cut a branch of the tree you could remove all the organisms that make up a clade
The “Old” Way…
• Taxonomy: The old way of classifying organisms
• In the 18th century, Carolus Linnaeus published a system of taxonomy based on resemblances
The “Old” Way…
• Two key features of his system remain
useful today: two-part names for
species (e.g. Vulpes vulpes) and
hierarchical classification
Taxonomy Rules
• Go in order of largest groups to specific groups – Domain, Kingdom, Phylum, Class, Order,
Family, Genus, Species • Dear King Phillip Came Over For Good Spaghetti
• Binomial nomenclature – Scientific names only! No common names
• Made up of Genus & Species name
• Genus is ALWAYS capitilized
• Species name is ALWAYS lowercase
• Write in italics… if you can’t = underline it!