Review: Review: What is Biodiversity?What is Biodiversity?

The diversity of lifeThe diversity of lifeExamples: Examples: There are over There are over 10,000 10,000

speciesspecies of of birds knownbirds known in the world, in the world, 900,000900,000 different different kindskinds of living of living insectsinsects, , about about 280280 known living known living species of species of monkey and about monkey and about 7878 speciesspecies of of whaleswhales, dolphins, and porpoises. , dolphins, and porpoises.

2. What were early 2. What were early beliefs on how so many beliefs on how so many different species different species developed?developed?

Before the 1800s, most people believed Before the 1800s, most people believed that species were unchanging. that species were unchanging.

In the early 1800s, a scientist by the In the early 1800s, a scientist by the name ofname of Lamarck Lamarck suggested that species suggested that species were not constant. He believed that new were not constant. He believed that new species evolved from preexisting species evolved from preexisting species. species. This was a big deal!!!!This was a big deal!!!!

3. What were Lamarck3. What were Lamarck’’s 2 s 2 Principles?Principles?

1) The more an animal uses a body part, the 1) The more an animal uses a body part, the stronger and bigger it becomes. If the body stronger and bigger it becomes. If the body part is not used, it becomes smaller and part is not used, it becomes smaller and weaker. This is called weaker. This is called the law of use and the law of use and disuse. disuse.

2) These changes in body parts could be 2) These changes in body parts could be passed from parent to offspring. This is called passed from parent to offspring. This is called the theory of the theory of the inheritance of acquired the inheritance of acquired characteristicscharacteristics. .

Right or Wrong? Right or Wrong?

4. Who is Charles Darwin? 4. Who is Charles Darwin? A Naturalist that Sailed A Naturalist that Sailed around the world from 1831-around the world from 1831-1836 studying nature and 1836 studying nature and collecting organisms. collecting organisms.

5. What important observations 5. What important observations did Darwin Make?did Darwin Make?

1.The diversity of living species was 1.The diversity of living species was far greater than anyone had far greater than anyone had previously known!!previously known!!

2. Organisms had unique adaptations2. Organisms had unique adaptations

3. Organisms with unique adaptations 3. Organisms with unique adaptations resembled other similar organisms. resembled other similar organisms.

4. Fossils of extinct species resembled 4. Fossils of extinct species resembled many living species. many living species.

What important What important observations did Darwin observations did Darwin Make Continued?Make Continued?

5. Organisms competed for 5. Organisms competed for resources like food, shelter, and resources like food, shelter, and mates. mates.

6. These observations led him to the 6. These observations led him to the idea of natural selection and idea of natural selection and helped him develop the theory of helped him develop the theory of evolution!!evolution!!

6. What is Natural 6. What is Natural Selection?Selection?

Due to genetic differences Due to genetic differences (mutations) , some organisms will (mutations) , some organisms will have a better chance at surviving have a better chance at surviving long enough to reproduce than long enough to reproduce than others. These beneficial traits will be others. These beneficial traits will be passed down through the passed down through the generations, producing change in a generations, producing change in a species over time. species over time.

Natural Selection Natural Selection Continued:Continued: The traits that help an organism The traits that help an organism

survive in a survive in a

particular particular

environment areenvironment are

““selectedselected”” by by

pressures in that pressures in that

environment. environment.

7. What are Selection 7. What are Selection Pressures?Pressures? Limiting Factors, or environmental Limiting Factors, or environmental

variables, that make it harder for variables, that make it harder for individuals to survive.individuals to survive.

Examples: Over population of a species, Examples: Over population of a species, limited food/space, disease, extreme limited food/space, disease, extreme environmental conditions, competition for environmental conditions, competition for mating rights. mating rights.

Individuals that are better equipped to deal Individuals that are better equipped to deal with these selection pressures are the ones with these selection pressures are the ones that will live long enough to reproduce. that will live long enough to reproduce.

8. Natural Selection 8. Natural Selection Video: Video:

Take 5 movie notes as you Take 5 movie notes as you watch the movie clip on watch the movie clip on Natural Selection.Natural Selection.

http://www.youtube.com/watch?v=0SCjhI86grU

Find a partner Find a partner NEARBYNEARBY and discuss the following and discuss the following questions:questions:

1. Do you believe in natural 1. Do you believe in natural selection?selection?

2. Do you believe that 2. Do you believe that organisms can change organisms can change over time? over time?

9. How does Natural 9. How does Natural Selection lead to Species Selection lead to Species Fitness?Fitness? Overtime, natural selection Overtime, natural selection

results in changes in the results in changes in the inherited characteristics of a inherited characteristics of a population. population.

These changes increase a These changes increase a species fitness (survival rate)species fitness (survival rate)

10. What is 10. What is ““Survival of Survival of the Fittest?the Fittest?””

Life is a struggle in which Life is a struggle in which only those organisms best only those organisms best adapted adapted (most fit) to (most fit) to existing conditions are existing conditions are able to survive and able to survive and reproduce. reproduce.

11. How does Natural 11. How does Natural Selection explain Descent Selection explain Descent with Modification.with Modification.

Each living Each living species has species has descended descended with changes with changes from other from other species over species over time.time.

12. How does natural 12. How does natural Selection help explain Selection help explain evolution? evolution? It explains how and It explains how and why species change why species change over time.over time.

13. What is Evolution?13. What is Evolution? Evolution: gradual change over Evolution: gradual change over

timetime1.1. Geological Evolution: Geological Evolution: Continuous Continuous

change in the Earth over the last change in the Earth over the last 4.5 billion years4.5 billion years

2.2. Organic Evolution: Organic Evolution: Changes in Changes in species over time. Modern species over time. Modern Species descended from ancient Species descended from ancient species through natural selection. species through natural selection.

14. Evolution Movie14. Evolution Movie

Take 5 Movie Notes: Take 5 Movie Notes: http://www.youtube.com/watch?v=GhHOjC4oxh8

Darwins 6 main points Quiz: Darwins 6 main points Quiz:

Read the descriptions on Read the descriptions on your paper and use the your paper and use the word bank to try and fill word bank to try and fill in the correct answers:in the correct answers:Natural Selection, Speciation, Natural Selection, Speciation,

Adaptations, Variation, Adaptations, Variation, Overproduction, Competition Overproduction, Competition

15. Darwin15. Darwin’’s 6 main points:s 6 main points: 1) Overproduction: 1) Overproduction: Species produce far Species produce far

more offspring than needed to maintain more offspring than needed to maintain a population. But, because only a small a population. But, because only a small fraction survive to adulthood, fraction survive to adulthood, population numbers remain relatively population numbers remain relatively constant. constant.

2) Competition: 2) Competition: Only a small number of Only a small number of offspring survive because organisms offspring survive because organisms must compete for a limited amount of must compete for a limited amount of resources. resources.

DarwinDarwin’’s 6 Main Pointss 6 Main Points3) Variations: 3) Variations: Not all members of a Not all members of a

population are exactly the same. population are exactly the same. Some are bigger, faster, stronger, Some are bigger, faster, stronger, than others. This is due to genetic than others. This is due to genetic differences among members. differences among members.

4) Adaptations: 4) Adaptations: These genetic These genetic differences between members of a differences between members of a population provide some organisms population provide some organisms with a better chance at winning the with a better chance at winning the competitions for these limited competitions for these limited resources. resources.

DarwinDarwin’’s 6 Main Pointss 6 Main Points 5) Natural Selection: 5) Natural Selection: Nature Nature ““selectsselects””

which organisms are best suited for which organisms are best suited for survival and reproduction. Those with survival and reproduction. Those with unfavorable traits donunfavorable traits don’’t survive long t survive long enough to reproduce.enough to reproduce.

6) Speciation: 6) Speciation: Overtime, only those Overtime, only those species with favorable traits will survive species with favorable traits will survive long enough to reproduce. They will pass long enough to reproduce. They will pass these traits on to their offspring, who are these traits on to their offspring, who are will probably have the same favorable will probably have the same favorable traits. Hence, a species emerges. traits. Hence, a species emerges.

What is Artificial What is Artificial Selection?Selection?

nature provides variation, humans select nature provides variation, humans select variations that are useful. variations that are useful.

Example - a farmer breeds only his best Example - a farmer breeds only his best livestocklivestock

13. Evidence of Evolution13. Evidence of Evolution

1.1. Fossil RecordFossil Record

2.2. Geographic Distribution of Living Geographic Distribution of Living SpeciesSpecies

3.3. Homologous Body structuresHomologous Body structures

4.4. Similarities in Embryology Similarities in Embryology

Evidence of Evidence of EvolutionEvolution

Fossil Record provides evidence Fossil Record provides evidence that living things have evolvedthat living things have evolved

Fossils show the history of life on Fossils show the history of life on earth and how different earth and how different groups of organisms have groups of organisms have changed over timechanged over time

Relative Relative vs. vs. Absolute Absolute DatingDating

Relative Relative DatingDating

Can determine a fossiCan determine a fossill’’s relative ages relative age

Performed by Performed by estimating fossil age estimating fossil age compared with that of compared with that of other fossilsother fossils

Drawbacks – provides Drawbacks – provides no info about age in no info about age in yearsyears

Absolute Absolute datingdating

Can determine the Can determine the absolute age in absolute age in numbersnumbers

Is performed by Is performed by radioactive dating – radioactive dating – based on the amount of based on the amount of remaining radioactive remaining radioactive isotopes remainisotopes remain

Drawbacks - part of the Drawbacks - part of the fossil is destroyed fossil is destroyed during the testduring the test

Carbon-14 DatingCarbon-14 Dating

Fossil Formation SGFossil Formation SG

Primate FossilsPrimate Fossils

Australopithecus Homo erectus Homo sapien

Primate Primate Brain Brain CapacityCapacity

Primate Bone structurePrimate Bone structure

Human RelativesHuman Relatives

AustralopithecusAustralopithecusafarensisafarensis

Homo habilis = handy humanHomo habilis = handy human1.5 to 2 mya1.5 to 2 mya

Homo erectusHomo erectus1.6 mya1.6 mya

bipedal

Neanderthals35,000 to 100,000 ya

Cro-Magnon35,000 to 40,000 ya

Modern Homo sapien(fully modern fossils 100,000 ya)

13. Evidence of 13. Evidence of EvolutionEvolution

2.2. Geographic Geographic Distribution of Living Distribution of Living SpeciesSpecies

Similar animals in Similar animals in different locations different locations were the product of were the product of different lines of different lines of descentdescent

13. Evidence 13. Evidence of of EvolutionEvolution

Homologous Body Homologous Body StructuresStructures

Structures that have Structures that have different mature different mature forms but develop forms but develop from the same from the same embryonic tissuesembryonic tissues

e.g. Wing of bat, e.g. Wing of bat, human arm, leg of human arm, leg of turtleturtle

Turtle

Alligator

Bird

Homologous Body Homologous Body StructuresStructures

Vestigial OrgansVestigial Organs

traces of homologous organs in other traces of homologous organs in other speciesspecies

Organ that serves no useful functionOrgan that serves no useful functione.g. Appendixe.g. Appendix

13. Evidence of 13. Evidence of EvolutionEvolution

Similarities in Similarities in EmbryologyEmbryology

In their early In their early stages of stages of development, development, chickens, turtles chickens, turtles and rats look and rats look similar, providing similar, providing evidence that evidence that they shared a they shared a common common ancestry.ancestry.

Embryological developmentEmbryological development