• 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

• 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 AIM: What are some pieces of evidence for evolution?evolution?

DO NOW: In your own words explain the DO NOW: In your own words explain the scientific explanation of the origin of life.scientific explanation of the origin of life.

Homework: Textbook Read pages 423-426 Homework: Textbook Read pages 423-426 questions 3 and 4 pg 430questions 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 Evolutiona) 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 Diagramsa) 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 EvolutionI. 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. Cytology

2. Anatomy (structure)

3. Development embryology

4. 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 Structuresa) 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 Embryologya) 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:

• 1. Sedimentary Rock

• 2. Burgess shale

• 3. Ice

• 4. Tar

• 5. Amber

Types of Fossils1. Complete organisms Molds and casts

can be preserved in ice, tar or amber

2. Partial remains (ex: skeleton)

3. Imprints or trace fossilsimpressions left by organism

4. Petrified fossilsgradual 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 Positionsin 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 Fossils1. All living organisms maintain small of amounts

of radioisotopes (ex: Carbon 14)

2. After death, radioisotopes change into non-radioactive “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 beginsautotrophic 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 EnvironmentBecause 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

• 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 FrequenciesWhy 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 IsolationAncestral species is split up into separate populations by physical barriers that prevent interbreeding

Physical Barriers include:

mountains, rivers, deserts, bodies of water

#2-Adaptive RadiationIsolated 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 DriftChanges in a population resulting from random events like:

1. Founder Effectinitial 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 Isolationa) 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.

A

B

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

• 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 organellesDouble membranes

Have DNAReproduce 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 144-top 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 whicheach 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

• 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

CompetitionInherited Variation

Natural Selection

• • 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 the ancestor

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) Theory3 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 Geneticsa) The study of changes in the genetic

characteristics of entire populations

b) used to study the rate of evolution

c) Gene Frequencythe % of one particular gene out of all the genes for one particular trait in a population

d) Gene poolall of the genes for all of the

characteristics in a population

Comparing Gene FrequenciesWhy 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

2. Natural Selection(unequal survival rates)

3. Non-random mating(unequal mating opportunities)

4. Small Population Size

5. Migration (organisms enter or leave the population)

1. No Mutations or balanced rates of mutation

2. Equal survival rates for all genotypes

3. Random mating (equal mating opportunities)

4. Large population size

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 Evolution1. Gradualism

species evolve slowly and steadily(traditionalists like Darwin believe in gradualism)

2. Punctuated Equilibriumspecies 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. Coevolutionwhen the evolution of one species is strongly

influenced by the evolution of anotherExample: insects and flowering plants

2. Divergent Evolutionwhen species or populations evolve in different

directions because of adaptation to different environmentsExample: black bear and polar bear

3. Convergent Evolutionwhen 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 DDT1. 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/english_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?