Transcript Organic Evolution - Sewanhaka Central High School District

• AIM: How are species related?
• DO NOW: Why do scientists develop
theories? Are theories facts? Why or why
not?
Scientific theory of the origin of
life
Francisco Redi:disproved
abiogenesis
Louis Pasteur
Louis Pasteur
• Pasteurization: boils liquids to kill microbes
• He found microscopic organisms live in
the air and water surrounding us
1920’s Alexander Oparin and John
Haldane: postulated conditions of
early earth
Theory of primordial Soup
• Hypothesized the early conditions of earth
• Boiling oceans, volcanic eruptions, lightning
storms
• Atmospheric gases methane (CH4),
ammonia (NH3), hydrogen (H2), and water
(H2O).
• Energy sources electric current through
lightning storms and sun’s UV light
• Early earth’s conditions interacted to form
amino acids and small nucleic acids
1953 Stanley Miller and Harold Urey
Miller and Urey
• Actually created a closed system
simulating early earth conditions
• Observed small simple organic
compounds were formed
– Amino acids
• Supports primordial soup hypothesis
From amino acids to the protocell
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Amino acids combines to form proteins
Proteins evolved into RNA
RNA into DNA
Somehow cell membranes were
synthesized it is still unclear how
How did the first types of cells
develop?
• Small organic compounds combine to
create some types of membrane
surrounding molecules and nucleic acid
• This was called a protocell
First cells
• Prokaryotes: no
nucleus
• Most likely
archaebacteria
How then did we go from single
celled prokaryotes to
eukaryotes?
Lynn Margulus: endosymbiont
theory
• 1960’s explains how eukaryotic cells arose
• Eukaryotic cells evolved from symbiotic
relationships with prokaryotic cells
• Evidence is seen in the DNA of both
chloroplasts and mitochondria of
eukaryotes which has more similarities to
prokaryotic DNA and not eukaryotic
Alternative theory of origin of life:
Deep sea vents
• Life originated in the
hydrothermal volcanic
vents in the deep sea
• Chemosynthesis: used
the digestion of living
things to make food
• Photosynthesis uses light
• Chemosynthesis uses
molecules
Assessment
• In your own words explain the scientific
explanation of the origin of life
 AIM: What are some pieces of evidence for
evolution?
 DO NOW: In your own words explain the
scientific explanation of the origin of life.
 Homework: Textbook Read pages 423-426
questions 3 and 4 pg 430
Organic Evolution
Organic Evolution
• The central idea of biological evolution is that all life on
Earth shares a common ancestor, just as you and your
cousins share a common grandmother.
• Biological evolution, simply put, is descent with
modification.
• Small-scale evolution (changes in gene frequency in a
population from one generation to the next)
• Basically offspring displays different traits than parents
• Large-scale evolution (the descent of different species
from a common ancestor over many generations).
Organic Evolution
a) Changes in the genetic characteristics of a
population over generations
b) Genetic changes alter:
proteins produced by organism
c) Changes in proteins affect:
biochemistry, structure, appearance,
reproduction, development, behavior,
disease resistance, etc, etc.
• AIM: How do scientists determine common
ancestry?
• Do NOW: 1- take out mondays homework Text
pg 383 RC page 385 question 2
• 2- Take out Darwin’s finches handout
• 3- EXPLAIN HOW each island has a different
species of finch bird
• HOMEWORK: 387 Reading Check. Page 389
question 2
Darwin’s descent with modification
• Each generation shows a slight variation
from the prior
• Successful variations remain in the gene
pool
• Unsuccessful variations are removed
Family Tree Diagrams
a) used to show probable
evolutionary relationships
b) some interpretations
c) multiple species can
evolve from a single
ancestor
d) many species have
become extinct
Evolution
• Change over time
• Natural selection vs Artificial Selection
• Natural selection: environmental conditions
are the selecting agents
• Artificial selection: humans are the
selecting agents
Thursday 5/10/12
• AIM: how is evolution seen through
history?
• DO NOW: What do genes code for and
how are genes related to descent with
modification?
Evidence for Evolution
I. Fossils
show structural changes
II. Comparative Sciences
• result from common ancestry
• the greater the similarity, the closer the
evolutionary relationship and the more
recent the common ancestor
• III. The geological record
• IV. Biogeography (Pangea)
Comparative Studies looks for
Similarities
Between Species
1.
2.
3.
4.
Cytology
Anatomy (structure)
Development embryology
Biochemistry
Cytology
a) cells with similar organelles appear in
virtually all species
b) similarities in cell structure suggest that all
organisms may have evolved from a single
ancestor
Comparative anatomy
• Compares the physical structures of
organisms within different species
– Homologous structures
– Analogous Structures
– Vestigial
Homologous Structures
a) structures in different
species that are truly
similar and develop in
the same way
b) ex: vertebrate forelimbs
c) result from common
ancestry
d) may now be used for
different purposes
Vestigial Structures (Vestiges)
a) useless structures “left over” from
ancestors
b) ex: snakes have small leg bones inherited
from their lizard ancestors
c) human vestiges include:
•
appendix
•
coccyx (tail bones)
• tonsils
Analogous structures
• Similar in function but not structure
• Gives evolutionary information about the
natural environment the organisms were
exposed to
• Does not give common ancestry
• Ex: wing of butterfly (chitin)
– Wing of bat (bones)
What is the closet common
ancestor of species I and N?
• AIM: How do scientists determine common ancestry?
• DO NOW: The study of homologous structures in mature
organisms provides evidence for the evolutionary
relationships among certain groups of organisms. Which
field of study includes this evidence of evolution?
1- comparative cytology 2- biochemistry
3- geology
4- comparative anatomy
Homework: Textbook Read pages 426-428.
Questions 10-13 page 445
Comparative Embryology
a) different species go through
similar stages of early
development
Studies the embryological
development of organisms
ComparativeBiochemistry
a) different species have many of the same
genes (DNA sequences) and produce
similar proteins
b) provide the most precise information for
determining evolutionary relationships
Comparing DNA Sequences
For A Specific Protein
Species #1: ATC CTA GCC TTT AAA
Species #2: ATC CTT GCC TAT AAA
Species #3: ATC CTA GCC TTT AAA
Species #4: ATT CTT GCG TAT AAA
1. Which two species are most closely related?
Answer: #1 and #3
2. Species #3 is _______closely related to species
#4 than it is to species #2
Answer: less
• AIM: How do fossils provide evidence for
evolution?
• DO NOW: What are homologous
structures? How do they give evidence to a
common ancestor?
Fossil Evidence for Evolution
Fossils are:
• naturally preserved
remains of dead
organisms
• show structural
changes resulting from
evolution
Fossils are found in:
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1. Sedimentary Rock
2. Burgess shale
3. Ice
4. Tar
5. Amber
Types of Fossils
1. Complete organisms Molds and casts
can be preserved in ice, tar or amber
2. Partial remains (ex: skeleton)
3. Imprints or trace fossils
impressions left by organism
4. Petrified fossils
gradual absorption of minerals turns the
remains into a stone like material
Fossil Samples
• Trace fossils
• Mold and cast
• Petrified fossils
• Replacement
• Amber
• Frozen
Fossil Formation
• Sedimentary Rock
• Burgess Shale
Friday 5/18/12
• AIM: how does the geological time scale
create a timeline for the origin of life
• DO NOW:In your own words explain how
fossils give us insight to common ancestry.
• HOMEWORK: Textbook pages 441-443
questions 1-8. WRITE OUT THE
QUESTION FOLLOWED BY THE
ANSWER
Determining The Age of Fossils
Relative dating:
1. Rock Layer Positions
in undisturbed layers of
sedimentary rock
the law of superposition
the deeper the layer,
the older the rock (& the
older & simpler the fossils)
2. Index Fossils
a) The age of these fossils is known
b) Other fossils found in same layer are the
same age
The fossils found in layer B resemble the fossils found in layer A.
This similarity suggests that
• 1-the fossils in layer B were formed before the fossils in layer
A
• 2-modern forms of life may have evolved from earlier forms of
life
• 3- vertebrate fossils are only found in sediments
• 4-the fossils in layer A must be more complex than those in
layer B
•
• Explanation: These fossils demonstrate
gradualism, the theory on the time frame of
evolution that states that species gradually
change over time. Since the fossils are
found in different layers of sedimentary
rock, the older layer contains species that
evolved into newer species with some
changes in the newer layer of rock.
• SPECIATION
•
develop of a new
species from a
previously existing
species
Gradualism vs Punctuated
equilibrium
• Both processes are referring to the development of
new species caused by natural selection
• In gradualism slight changes in each generation
lead to a longer, slower speciation process
• In punctuated equilibrium an extreme
environmental change caused a rapid shift in the
gene pool leading to a quick speciation process
3. Radioactive Dating of Fossils
1. All living organisms maintain small of amounts
of radioisotopes (ex: Carbon 14)
2. After death, radioisotopes change into nonradioactive “decay” products
3. Ratio of decay product to radioisotope increases
over time and can be used to estimate fossil’s
age
4. Half life: the amount of time it takes for half of
the atoms of a radioactive element to decay
If the half-life of carbon-14 is
5800 years, how old is this
specimen after 3 half lives?
5,800 yrs
11,600 yrs
17,400 yrs
Half Lives
Radioisotope
Decay Products
O
2000 grams
O
1
1000 grams
1000 grams
2
500 grams
1500 grams
3
250 grams
1750 grams
The geological time scale
• Derived from the
examination of fossils
• Explains major
geological and
biological events in
the earths history
Divides into 4 major eras
• Precambrian Era: Life
beginsautotrophic prokaryote
eukaryotes multicellular eukaryotes
• Paleozoic Era: Cambrian explosion:
ancestors of most animal groups.
• Mesozoic Era: Dinosaurs. K-T boundary
• Cenozoic Era: Mammals. Humans
Extinction
• Each era ended with mass extinction
• Extinction: all individuals within a species
dies forever!!!!
– The species is never seen again in evolutionary
history
Conclusions Based on
Fossil Record
1. Earth is about 4.5 Billion old
2. First organisms were bacteria and evolved
about 3.2 Billion years ago
3. Biodiversity (the variety of different species) has
increased
4. Organisms have become more complex
5. Most species became extinct
6. Life first evolved in the water, land organisms
evolved more recently
Adaptation to Environment
Because organisms with superior traits
produce more offspring than organisms with
inferior traits the next generation will have…
a) a higher % of superior characteristics and a
lower % of inferior characteristics and …
b) be better suited to it’s environment
• AIM: How does an entire new species
evolve from a parent species?
• DO NOW: Handout. Observe the pictures.
Explain what is happening from picture 1-5.
Which individuals survive and explain
WHY.
• Homework: page 453 Reading check
• Exam Friday
If the earth’s history (4.5 Billion
Years) was compressed into 1 day
• 12:00:01 AM - formation of the earth
• 7:00 AM – life begins (prokaryotic bacteria)
• 2:00 PM –first eukaryotic organisms
• 6:30 PM – first multicellular organisms
• 10:00 PM – first land organisms
• 11:59: 58 PM – humans evolve
• If you were trying to determine the age of a
fossil, would you rather use relative or
radiometric dating? Why or why not?
• AIM: How does an entire new species
evolve from a parent species?
• DO NOW: What are the different pieces of
evidence for evolution?
• What are the 2 mechanisms of evolution?
Review
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The fossil record
Comparative Sciences
The geological time scale
Biogeography
• How does the biogeographical location of a
species give evidence for evolution?
Biogeography
• Looks at the location of
species and their
environment
• Pangea: the
supercontinent
• Plate tectonics
• Species found in similar
climates all over the world
have similar
characterisitcs
What is speciation?
Speciation
• The evolution of two or
more species from a
common ancestor
Important example:
the Evolution of Finches on
the Galapagos islands
Peppered Moths
• Before Industrial
Revolution
• After Industrial
Revolution
2. Air pollution caused soot
to accumulate in major
cities
3. In polluted areas, light
colored moths were more
likely to be eaten by birds
4. Moths evolved from
mostly light to mostly dark
color in a short period
Comparing Gene Frequencies
Why are these gene
frequencies changing?
“A” increases chances of
survival and is more
likely to be passed on to
offspring
Assessment
Adaptations
• adaptation in biology is a trait with a
current functional role in the life history of
an organism that is maintained and evolved
by means of natural selection.
• Adaptations usually occur because a gene
mutates or changes by accident
• Structural adaptations
• Behavioral adaptations
Mimicry
Mimicry
• One species looks or acts like a different
species in order to increase survival
3 Steps in Speciation
Geographic Isolation
Adaptive Radiation
Reproductive Isolation
#1-Geographic Isolation
Ancestral species is split up into separate
populations by physical barriers that prevent
interbreeding
Physical Barriers include:
mountains, rivers, deserts, bodies of water
#2-Adaptive Radiation
Isolated populations begin to evolve in
different directions due to:
A. Natural Selection
(they adapt to different environments)
B. Genetic Drift
(random events)
Pd 7pd 2 Monday Friday
Genetic Drift
Changes in a population resulting from
random events like:
1. Founder Effect
initial differences between groups founder
population is majority
2. Different Mutations occur in each group
3. Sexual Reproduction produces different
combinations in each group
4. Accidental Deaths
Animations
Genetic drift Founder effect
Genetic drift: Founder Effect
• When a small part of a population moves to
a new locale, or when the population is
reduced to a small size because of some
environmental change,
• the genes of the "founders" are the majority
• EX: Polydactyl (6 fingers) Amish people
Genetic drift: bottleneck effect
#3-Reproductive Isolation
a) Groups have become so different that they
can no longer interbreed if reunited
b) May result from differences in anatomy,
behavior, body chemistry,mating season,
chromosome content
c) Isolated groups are now considered to be
separate species
The graph below shows changes in
the populations of two species that
interact only with each other over a
period of time. In a complete
sentence describes the two species.
B
A
Monday 5/7/12
• AIM: How does evolution work?
• DO NOW: If you were a hawk looking for food,
which of the rabbits would you dive for and why?
HOMEWORK
• Read 382-383. RC on 383. Page 385 q 2
• How does competition cause a shift in the
gene pool?
– Variation within a species causes different
methods of competition
– The individuals with successful adaptations will
survive and reproduce passing the successful
trait to offspring
List in order the scientists who
helped develop the scientific theory
of the origin of life
Origin of Life
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Primordial Soup
Amino acids and small nucleic acids
Protocell
Anaerobic prokaryote
Aerobic prokaryote
Single celled Eukaryote
Multicelled eukaryotes
How are the mitochondria and
chloroplasts similar to prokaryotes?
Large organelles
Double membranes
Have DNA
Reproduce as needed
Use oxygen
How did the earth become
biodiverse?
• Evolution is the process by which modern
organisms have descended from ancient
ancestors.
• Evolution is responsible for both the
remarkable similarities we see across all life
and the amazing diversity of that life — but
exactly how does it work?
Three Theories of Evolution
Lamarck
Darwin
Modern Synthesis
Lamarck’s Theory (Use and Disuse)
1) 1st major theory of evolution
2) Lamarck believed that:
a) evolution occurs in response to “need”
b) acquired characteristics could be passed on
ex 1) if you learn a lot, you’ll have smarter kids
ex 2) if you use an organ it will be larger in
offspring, if you don’t it will shrink
3) Experiments showed that Lamarck was wrong
Use and disuse: Giraffe necks are long
because they use them
• AIM: How did the earth become so biodiverse?
• DO NOW: 1- Regents review book read page 144top of 145. In your own words, what is organic
evolution?
2- Read pages 151-top 152. List and briefly
describe the three modifications to the theory of
evolution.
Homework:Regents Review book page 370
questions 15 and 16. page 382 question 41
Thursday 5/3/12
• AIM: What are the major concepts that
helped Darwin develop his Theory of
evolution by natural selection?
• DO NOW: Copy the side board and fill in
the boxes
• HOMEWORK:Text page 381 Reading
check and page 385 questions 1 and 2
Charles Darwin: 1809-1882
• Proposed a mechanism for
biodiversity
• From 1831 to 1836
Darwin served as
naturalist aboard the
H.M.S. Beagle
• Visited places around the
world
• Studied plants and animals
everywhere he went
The Father of Evolution
• I have called this principle, by which
each slight variation, if useful, is
preserved, by the term Natural Selection.
—Charles Darwin from "The Origin of Species“
• November 24, 1859
How did Charles Darwin develop
his Theory?
Darwin’s observations
• Specifically he paid close attention to the finch
birds on each island
• He looked at their beaks
• He determined that each finch had a different beak
shaped specifically for the food which was
available to them
• He also noticed that finches on the Galapagos
resembled finches in similar environments in other
parts of the world
Darwin’s observations
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Overproduciton
Competition
Variation
Survival of the fittest
Thursday 3/25/10
• AIM: How did Darwin develop his theory of
evolution by Natural Selection?
• Homework: RRB page 373 question 22. Page 369
questions 13 and 14
DO NOW:the cactus
warbler & wood pecker finch
All live on one island.
Which of these finches is least
likely to compete with the
Other two?
Darwin’s Theory (Natural Selection)
Overproduction
Struggle for Existence
Competition
Inherited Variation
Natural Selection
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Survival of the fittest
Adaptation to Environment
Overproduction
• Species produce many more offspring than
environment can support
• Population size is limited by:
space, food supply, disease, predators, etc.
Struggle for Existence
• Overproduction of offspring creates
competition for survival between the
members of the species
Survival of the fittest
• Fitness: refers to physical or behavioral
characteristic that helps survival
• The most fit individuals are those capable of
getting the food, shelter, females etc.
Friday 5/4/12
• AIM: how does nature choose fitness?
• DO NOW: In your own words, explain how
competition causes survival of the fittest.
• Overproduction causes competition
– There are too many individuals
– The environment cannot maintain
• Individual variation causes different methods of
survival
– The variation with the greatest chance of survival is
said to be the fittest
– These individuals survive and reproduce passing the
fit trait to their offspring
– Over a period of time this shifts the observed
phenotype in the population (evolution)
– NATURE CHOOSES FITNESS
It is important to note
• If Nature drastically changes, the definition
of fitness may change
– Ex: Himalayan Rabbits
Inherited Variations
• All populations have variations
that can be passed to offspring
• New variations can arise spontaneously and
may be harmful or beneficial
• Weakness in Darwin’s Theory:
failure to account for the sources of
variation
Natural Selection
(Survival of the Fittest)
• In the “struggle for existence” between
members of a species, the ones with the
best “adaptations” for their particular
environment (the “fittest”) are most likely
to survive and reproduce
• “Adaptations” are inherited characteristics
which improve the chances of survival
and / or reproduction
Darwin was afraid of the skepticism
• Because of the strong religious beliefs of his
time Darwin did not want to use the word
“evolution”
• He called his observations Descent with
modification
– Current day species descended from ancestral
species
– Natural selection is the mechanism for descent with
modification (changes in observed characterisitcs in
a species over a period of time)
• The more characteristics in common, the closer
Click on: Watch Darwin Video
• Darwin | American Museum of Natural
History
Theory of Evolution by Natural
Selection
• In a varied population, Nature chooses
which traits are best fit for survival.
• As Nature changes, new variants become fit
so over a long period of time there is a shift
in observed characteristics of the population
Why was Darwin’s Theory of
Natural selection incomplete?
Darwin had no idea how variation
occurred
• Gregor Mendel, Hugo deVries and Thomus
Hunt Morgan were all geneticists who
helped figure out the source of variation.
• Genetic Recombination: crossing over
during gamete formation
• Genetic Mutation: random changes in gene
Selecting agents
• Factors that choose fitness
– Ex: temperature, predators, pH, habitat, water
availability
Evolution
• Natural selection
– Nature is the
determining factor
• Artificial selection
– Humans are the
selecting factors
Modern (Synthetic) Theory
3 Components
#1. Darwin’s Theory of Natural Selection
( he was correct, but his explanations
were incomplete)
#2. An Explanation of the Sources of
Inherited Variations
Genetic recombination (meiosis) and mutation
#3. Population Genetics
Sources of Inherited Variation
#1 Mutations
a) random changes in genes
b) generally harmful and recessive
c) if most mutations are harmful, how can
they contribute to improvements in a
species?
d) natural selection preserves good
mutations while eliminating harmful
ones
#2 Genetic Recombination
a) Homologous chromosomes swap
information during Prophase 1 of meiosis
b) refers to inherited variations resulting
from sexual reproduction
b) sexual reproduction creates variety
through:
meiosis, fertilization & crossing over
Genetic Variety and Extinction
• The greater the genetic variety within a
species the greater the chance that some can
survive in a changed environment.
• If the environment changes, the definition of
fitness may change
• Ex: Peppered moths in Manchester England
Peppered Moths
• Before Industrial
Revolution
• After Industrial
Revolution
Mechanisms for evolution
• Punctuated
equilibrium
• Gradualism
Go to evidence for evolution
• AIM: How is evolution in action in current
day species?
• DO NOW: In your own words explain the
greatest chance of variation within a species
• In your own words explain how fossils
give us insight to common ancestry.
Microevolution vs
Macroevolution
Micorevolution
• Looks at change in gene
pool of a population
• Shows a shift in the
observed traits within a
specific population
Macroevoultion
• Looks at the major
changes within the entire
history of life
• Studies the origin of life or
new species developments
• Mostly seen in the fossil
record
Population Genetics
a) The study of changes in the genetic
characteristics of entire populations
b) used to study the rate of evolution
c) Gene Frequency
the % of one particular gene out of all
the genes for one particular trait in a
population
d) Gene pool
all of the genes for all of the characteristics in
a population
Comparing Gene Frequencies
Why are these gene
frequencies changing?
“A” increases chances of
survival and is more
likely to be passed on to
offspring
Conditions that Conditions that
alter gene %
stabilize gene%
1. Mutations
1. No Mutations or balanced
rates of mutation
2. Natural Selection
2. Equal survival rates for
(unequal survival rates)
all genotypes
3. Non-random mating
(unequal mating
opportunities)
3. Random mating (equal
mating opportunities)
4. Small Population Size 4. Large population size
5. Migration (organisms
enter or leave the
population)
5. No migration
Factors that Affect the Rate of
Evolution
#1 Rate of Environmental Change **
if rate of environmental change increases, rate of
evolution must increase
#2 Time Between Generations
as TBG increases, capacity for rapid
evolution decreases
#3 Method of Reproduction
sexual reproduction increases capacity for
rapid evolution
#4 Competition Within Species
as competition increases, evolution rate increases
Two Theories About the Rate of Evolution
1. Gradualism
species evolve slowly and steadily
(traditionalists like Darwin believe in gradualism)
2. Punctuated Equilibrium
species may remain relatively stable for many
generations and then change dramatically in a
short period
Both theories may be correct:
some species have evolved gradually while
others may have evolved in abrupt spurts
Which type of evolution rate is
represented in each graph?
1. Coevolution
when the evolution of one species is strongly
influenced by the evolution of another
Example: insects and flowering plants
2. Divergent Evolution
when species or populations evolve in different
directions because of adaptation to different
environments
Example: black bear and polar bear
3. Convergent Evolution
when unrelated species evolve similar characteristics
because they are adapting to similar environments
Example: polar bear and artic fox
Which pattern
of evolution is
shown by each
picture?
• AIM: How is evolution in effect today?
• DO NOW: List at least 2 things that would
cause a shift in the gene frequency.
Artificial Selection
When humans have a strong influence on the
evolution of another species
Humans choose fitness
shift gene frequency and may cause
speciation
Selective breeding
• Humans choose organisms with desired
characteristics and breed them
Ex: #1-Antibiotic Resistance in Bacteria
1) when penicillin was first used it killed over 99%
of bacteria exposed to it
2) some bacteria contain a gene which makes
them resistant to penicillin
3) resistant bacteria survive use of penicillin and
pass their resistance on to offspring
4) many bacteria are now resistant to penicillin and
other antibiotics
5) antibiotics have been overused
Ex.#2- Industrial Melanism in Urban
Moths
1. Before industrialization,
most city moths were
light in color because
dark moths were more
easily seen by bird
predators
Ex.#3-Resistance to DDT
1. When first used, this insecticide killed
almost all exposed insects
2. A small % of insects were genetically
resistant and survived use of DDT
3. Resistant insects reproduced passing on
their resistance to offspring
4. DDT resistance is now widespread
What has caused an increase in
DDT resistant mosquitoes?
HIV drug resistance
• http://www.biocreations.com/animations/en
glish_HIV/main.swf
Human Immunodeficiency Virus
• Once it enters the body, it infects White
blood cells
• It uses the white blood cell to make more
viruses
• The new viruses then infect more cells
• Certain medications can prevent the HIV
virus from replicating so it cannot infect any
new cells
Resistance
• HIV is a very sophisticated virus
• It has mutated (changed) and created
variation that are resistant to medicine
• AIM: How do scientists classify species?
• DO NOW: If you were a scientist exploring
unchartered land and you came across 2
new “animals” how would you determine
their relatedness?