Download EVOLUTION- change in species over time

EVOLUTION- change in species over time
Jean
Baptiste de
Lamarck
Charles
Darwin
5 evidences
of evolution
3 patterns
of evolution
Homologous structures
Theory of
Acquired
Traits
aka
“use it
or lose
it”
Theory of
Natural
Selection
Coevolution
Analogous structures
Vestigial structures
aka
“survival
of the
fittest”
Convergent
evolution
Similarities in Embryology
Similarities in
Macromolecules
Divergent
evolution
EARLY EARTH:
•The Earth is roughly 4.5 billion years old.
-Q: How do we know this?
-A: radiological testing on the different layers of the Earth
•Scientists use radioactive dating to determine the „age‟ of each layer of earth
•Earth‟s atmosphere was very different compared to today‟s atmosphere
•The temperature was very hot
•There was hardly any oxygen in the air
•Due to the fact that there was NO oxygen in the air, the 1st cells on this planet were anaerobic
(because they do NOT need oxygen)
•Also the 1st cells were prokaryotic NOT eukaryotic
-Q: What are some differences between prokaryotic cells and eukaryotic cells?
PROKARYOTIC CELLS
EUKARYOTIC CELLS
FOSSILS:
•A fossil is a trace of a long DEAD organism
•2Types of fossils:
1.Moldothis type of fossil is an imprint in a rock
oshows the shape of the organism
2.CastoThis type of fossil is a mold that is now filled with minerals
oThis is a „rock-like‟ 3D structure of the organism
Cast
fossil
•In 1668 Robert Hooke said that fossils were the remains of animals & plants that were once
alive
•In 1669 Nicolaus Steno came up with the Law of Superposition
-This law states that layers of rock are deposited on top of another by wind or water
-The lowest layer of the Earth is the oldest
-The top layer of the Earth is the youngest (newest)
-Fossils in the same layer of the Earth are roughly the same age
•There are 2 ways to find the age of a fossil:
-Relative age- is NOT an actual age, it is just whether 1 fossil is older or younger than
another fossil
-Absolute age- this is an actual age of the fossil, estimated by radiological evidence
•Answer the questions based on the picture below:
Q1: Which layer is the „oldest‟ layer? ________
Q2: Which layer is the „youngest‟ layer? _______
Q3: What could you say about the fossil found in layer C compared to the fossil in layer A?
_______________________________________________________________
Review questions:
1. Explain the difference between a mold fossil and a cast fossil.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
2.Compare and contrast prokaryotic cells with eukaryotic cells. Be sure to mention at least 2
similarities and 2 differences.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
3. Explain the difference between a fossil‟s „relative age‟ and „absolute age‟.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
WHAT IS EVOLUTION?
•Evolution- the change in species over time
-Q: What is a species?
-A: 1 type of organism that can produce fertile offspring
Theories of Evolution:
•Jean Baptiste de Lamarck (1744-1829)
-Using fossil evidence, he said that similar species come from a common ancestor
-His hypothesis: Theory of Acquired Traits (“use it or lose it”)
o States that traits are NOT determined by genes (DNA)
Example: Ducks have webbed feet because they repeatedly stretch their toes,
which caused webbed toes.
So now, when this duck reproduces, its offspring will also have webbed feet
o He also said that if an organism doesn‟t use a body part, then their offspring would
have a small version of that body part
Example: A crab‟s claw- if the crab NEVER used one of his claws, then when it
reproduced, its offspring would have a small claw (or no claw)
Theory of Acquired Traits (“use it or lose it”)
Here’s another example using the GIRAFFE.
This is his explanation as to why they have a long neck.
•We know that
this is NOT true!!
•Your traits are
determined by
DNA - (your
genes)!!
http://player.discoveryeducation.com/index.cfm?guidAssetId=F1843C7D-7D9D-411C-ABD7783ABF3BD0DD&blnFromSearch=1&productcode=US
Darwin develops a non-random
theory-3:20
Charles Darwin (1809-1882)
http://player.discoveryeducation.com/index.cfm?guidAssetId=9E8
DE1D4-BCBD-422C-B307E79CA309E95C&blnFromSearch=1&productcode=US
Darwin’s discoveries- 10:08
•He also said that similar species come from a common ancestor
•His hypothesis: Theory of Natural Selection (“survival of the fittest”)
oThis states that the organism that is best suited to their environment is the one that will
reproduce more successfully than others
oSo…..their genes get passed on & on & on & on……
•How did he arrive at this?
oHe took a trip on a boat called the HMS Beagle
oHe went to the islands off the coast of Ecuador called the Galapagos Islands
oThere he studied MANY organisms, one of them was a bird called the finch
He found 13 different types of finches, all with different types of beaks
Some had BIG/THICK beaks- these finches ate hard foods like seeds & nuts
Some had SMALL/THIN beaks- these finches ate soft foods like insects & berries
Answer the questions below using the illustration from above.
Q1: Which finch would have a diet of different types of really hard food? Explain your answer.
_______________________________________________________________________________
Q2: Which finch would have a diet of softer types of food like insects, that are in small hard to
reach areas, like a small hole? Explain your answer.
_______________________________________________________________________________
_______________________________________________________________________________
Q3: Which finch would have a diet of softer types of food, like berries? Explain your answer.
_______________________________________________________________________________
Q4: Which finch would have a diet of somewhat hard types of food? Explain your answer.
_______________________________________________________________________________
•Darwin discussed how the environment may affect the population of an organism
•ADAPTATION:
 If a species becomes better suited for its environment, then it will be more likely to survive
than other species that CANNOT adapt to their environment.
Example: Peppered moths
oBEFORE the Industrial Revolution:
Tree trunks were lighter in color,
Peppered moths- HARD to find (camouflage)
oso these moths would survive & reproduce and their population would
increase
Black moths- EASY to find
oso they would be eaten and could NOT reproduce, so their population would
decrease
ADAPTATION continued:
oAFTER the Industrial Revolution:
THE EVIRONMENT CHANGES!
Tree trunks are now DARKER in color (due
to pollution)
Peppered moths- EASY to find
oSo these moths would be eaten and
could NOT reproduce, so their
population would decrease
Black moths- HARD to find
(camouflage)
oSo these moths would survive &
reproduce and their population would
increase
BEFORE:
AFTER:
5 EVIDENCES OF EVOLUTION:
-The 5 evidences of evolution are:
http://player.discoveryeducation.com/index.cf
m?guidAssetId=E8C6C371-63AD-41D5-BF958F69D2A69B07&blnFromSearch=1&productco
de=US Support of theory of evolution- 6:37
-1. Homologous structures
2. Analogous structures
-3. Vestigial structures
4. Similarities in Embryology
-5. Similarities in Macromolecules
1. Homologous structures:
• Similar structures that come from a common ancestor
•Example- Arm of a human, cat, whale & bat – ALL have the same bones, but they‟re
different shapes & sizes!
2. Analogous structures:
•Look different but they ALL serve the same job
•Example- Wing of insect, seagull, bird, & batthe JOB is to fly
3. Vestigial structures:
•Useless structure that was once useful in an ancestor, but now is NOT used by the modern
organism
•Example- Whale’s pelvis- indicates that the „modern whale‟ came from an organism that
once walked on land- because it had a pelvis & femur
http://www.pbs
.org/wgbh/evol
ution/library/0
3/4/l_034_05.h
tml
Whale evolution- 5:09
4. Similarities in Embryology:
•In the early stages of embryonic development, ALL vertebrates are similar
(eventually that will fade as developments proceeds)
•Example- Fish, Turtle, Bird, Pig, & Human embryos
Q: What are some of
the features that
they ALL have?
A: _________________
_________________
_________________
_________________
5. Similarities in Macromolecules:
•The more similar species are to each other- the more similar their macromolecules
Q: What are some examples of macromolecules?
A: proteins, nucleic acids (DNA/ RNA)
•Example- Hemoglobin (protein found on Red Blood Cells)
Q1: What are proteins made up of?
A1: Amino Acids
Q2: What is the job of hemoglobin?
A2: to carry oxygen & carbon dioxide throughout the body
There is 1 difference between the Amino Acids of the human hemoglobin & the gorilla‟s
hemoglobin
There are 10 differences between the Amino Acids of the human hemoglobin & the lemur‟s
hemoglobin
Q3: Based on the information above, which organism’s HEMOGLOBIN is most similar
to our hemoglobin?
A3: gorilla
PATTERNS OF EVOLUTION:
There are 3 patterns of evolution:
1. Coevolution
2. Convergent Evolution
3. Divergent Evolution
1.COEVOLUTION•change in 2 or more species that are in close association with each other
Example- Flowers & Bees
Flower
• has a nice smell to attract the insect
•has a bright color so the insect can see it
Bee
•has a body that fits into the flower
•picks up pollen when its body touches the
flower.
•when it flies away to a different flower, the
pollen falls off and lands on this flower.
•the bee just fertilized these 2 flowers!!
2. CONVERGENT EVOLUTION•2 different species APPEAR to be very similar, but are NOT closely related
•This occurs when the environment selects similar phenotypes even though their ancestors
are very different.
•Example: shark & dolphin
Q1: What are some of the physical characteristics they BOTH have in common?
A1: dorsal fin, sleek body shape, pointed face, tail, fins
-Living in the ocean they need these characteristics in order to survive!
Q2: What’s the MAJOR difference between the shark & dolphin?
A2: shark is a fish; dolphin is a mammal
3. DIVERGENT EVOLUTION•When species becomes more dissimilar as a response to changing environments
•2 types of divergent evolution:
i. Adaptive Radiation- evolve from 1 species
othis happens naturally and very slowly
Example- Finches•all diverged in response to availability of different food found in their
environment
DIVERGENT EVOLUTION (continued)
ii. Artificial Selection- this does NOT happen naturally
•This happens very FAST
Example- Breeding dogs•humans select what traits they want their dog to have
•dog breeders know which 2 dogs to mate
•there are lots of different types of dogs today that were NOT around 20 years
ago!
•this type of divergent evolution happens much FASTER than what would
happen in nature
FOR EVOLUTION TO OCCUR:
•4 things are needed for evolution to occur:
1. Mutations
2. Migration
3. Genetic drift
4. Natural selection
1. Mutations- mutations are mistakes in DNA
•Not all mutations are bad, some mutations are good
•Mutations happen at a slow rate, but if exposed to mutagens (like chemicals) the rate
will be much faster
2. Migration- the moving of organisms either into or out of a population
i. Immigration- movement of organisms into a population
othis will cause the population size to increase
ii. Emigration- movement of organisms out of a population
othis will cause the population size to decrease
-this will cause a change in the gene pool of this population
Q: What is a gene pool?
A: total genetic information available in a population
3. Genetic drift- occurs in a small population
•Alleles can disappear completely over a few generations
•This means, traits can disappear from a population
4. Natural selection- aka- “survival of the fittest”
•Those that can adapt to their environment will survive and continue to pass on their genes
Gradualism- The theory that evolution happens very slowly
Speciation-
the process of species formation
•Begins with geographical isolation
•This is the physical separation of members of a population
-Q: What are some ways a population be geographically separated?
-A: river, canyon, mountains
•When a population is separated, the gene flow between them STOPS
•The 2 populations will begin to diverge because of natural selection & genetic drift
Example- Blue-headed wrasse & Cortez rainbow wrasse