Evolution

CHOOSE AN ANIMAL

• As a table, decide on an animal that is relatively well-known.

• What is this animal’s habitat?

• What does this animal eat?

Evolution

DESCRIBE FEATURES• What feature of the animal helps it to get

its food?

• What feature of the animal helps it to avoid predators?

• What feature of the animal helps it to attract mates?

• Is this animal nocturnal (night) or diurnal (day)?

Evolution

IS IT IN THE GENES?

Which of these features is controlled or primarily influenced by genes?

Evolution

MUTATE!• Choose one trait and mutate it in some

believable way. List this new trait in mutation 1 column next to the feature you mutated.

• Repeat the previous step 3 more times. You may mutate the same gene every time, or you can choose all different genes to mutate, or any combination.

Evolution

FINAL TRAITS

• List all features that the species currently have after the four rounds of mutation.

Evolution

ENVIRONMENTAL CHANGE

• While these mutations were occurring, a new predator moved into the ecosystem that tracks animals at night with powerful echolocation (radar that senses movement) to capture prey. No visual hunting.

Evolution

QUESTION 1Will your animal still survive with this

new predator in its environment? Explain why or why not.Consequence:Consequence: No = Extinction

Yes = Adaptation

Evolution

QUESTION 2Would your animal still mate

with the original animal if they were together in time. Explain why or why not.Consequence:Consequence: No = speciation = new species

Yes = species Variation

Evolution

What have we just done?

EVOLUTION!

Evolution

What happened to this population of organisms?

• Mutations in genes occur randomly.

• Changes in the environment may cause certain mutations to become an advantage and others to become a disadvantage.

• Advantageous mutations are passed on to offspring and over time, more offspring will have this advantage (adaptation).

Evolution

Mutation Random, Survival is not!

• There is no advance warning that an environmental change will occur, like you had no warning today.

• Mutation creating variation is random – not on purpose or to match a species need for something.

• Effect of changes in environment is not random. Those whose mutations were not an advantage died because they did not posses the right adaptations.

Evolution

WHAT DOES THIS MEAN?• Genetic variation (mutation) and changes in

the environment without advanced planning, eventually lead to the formation of new species.

• Adaptation and speciation are the two main events in evolution. As shown in this simulation, they seem to be the natural

consequence of natural events.

Evolution

Section Outline

Ideas That Shaped Darwin’s ThinkingA. An Ancient, Changing Earth

1. Hutton’s Theory of Geological Change2. Lyell’s Principles of Geology

B. Lamarck’s Theory of Evolution1. Tendency Toward Perfection2. Use and Disuse3. Inheritance of Acquired Traits4. Evaluating Lamarck’s Theory

C. Population Growth

Section 15-2

Evolution

Evolution

I. The Theory of Evolution

• A. What is a theory?

– A well supported, testable explanation of phenomena of the natural world

What is the Theory of Evolution?

Evolution

I. The Theory of Evolution

1.As environments change, species either possess the ability to adapt or they will go extinct.

2.Adaptation: an inherited trait that increases an organisms chance of survival.

Evolution -change over timeB. Evolution (biology) – changes in a population over time or descent with modification

EvolutionTypes of Adaptations

• Physical adaptations– Protective coloring

• Physiological Adaptations– Disease resistance

• Behavioral Adaptations– Social insects

Evolution

Hutton and Lyell - geologist

Hutton publishes his theory about geological forces that have and are continuing to shape the earth (Uplift, earthquakes).

Fossilized seashells are found on HIGH

mountains, and in vast layers of fossilized sediment (limestone,sandstone)

Earth must be millions of years old since mountain rise to great heights carrying organisms from ancient seas

Evolution

Uniformitarianism is the prevailing theory of geologic change.

Evolution

Sea level

Sedimentary rocks form in horizontal layers.

When part of Earth’s crust is compressed, a bend in a rock forms, tilting the rock layers.

As the surface erodes due to water, wind, waves, or glaciers, the older rock surface is exposed.

New sediment is then deposited above the exposed older rock surface.

Movement of Earth’s CrustSection 15-2

Sea level

Evolution

Early scientists proposed ideas about evolution.

Evolution is the biological change process by which descendants come to differ from their ancestors.

A species is a group of organisms that can reproduce and have fertile offspring.

Evolution

• There were many important naturalists in the 18th century.

– Linnaeus: classification system from kingdom to species– Buffon: species shared ancestors rather than arising

separately– E. Darwin: more-complex forms developed from less-

complex forms (Charles Darwin’s Grandfather)– Lamarck: environmental change leads to use or disuse

of a structure

Evolution

C. Jean-Baptiste Lamarck

• Argued that organisms acquire or lose certain traits during their lifetime by use or disuse AND pass them on to offspring.

Wrong!

Theory of Acquired Characteristics

Evolution

Lamarck (1809)-theory of "acquired characteristics"

Species evolve (change) by keeping traits that their parents developed.

EXAMPLE: Arnold Schwartzeneger's children will all have developed muscles

EXAMPLE: Giraffes' necks became longer and longer as they tried to reach higher leaves - longer neck could be inherited by offspring

EXAMPLE: IF your mother practiced piano and became a great player, her children will play well

Evolution

Figure 15–7 Lamarck’s Theory of Evolution

Evolution Darwin reads Malthus.

1838, Essay on Population: human population growth will eventually lead to not enough space and food for everyone. HOWEVER famine, disease and war limit population growth

Darwin applies this to all organisms. Populations in wild limited by amount of food and space too, so why do some survive and others not?

Evolution

KEY CONCEPT There were theories of biological and geologic change before Darwin.

Evolution

Theories of geologic change set the stage for Darwin’s theory.There were three theories of geologic change.

– Catastrophism: Floods, Earthquakes and Vulcanism change the shape of the earth

–Gradualism: Change occurs over a long period of time– Uniformitarianism: The laying down of sedimentary rock–layers is a uniform process continuing today.

13.1 Ecologists Study Relationships

II. Charles Darwin (1809-1882)

“. . .a theory of descent with modification through

variation and natural selection.”

Origin of Species, 1859

Evolution Ideas of Darwin’s Time• Many believed that Earth was only a few thousand

years old and neither the planet nor the species that inhabited it had changed since the beginning of time.

Evolution

Challenges to Common Beliefs

• During Darwin’s time, many fossils were being discovered which challenged the notion that life had not changed since Earth was formed.

Evolution

A. Scientific Research raised questions:

1. How do we account for fossils of species that appear to be extinct?

Evolution

What is a fossil?

• physical evidence of an organism that lived long ago.• Examples: skeletons, shells, leaves, seeds, imprints,

tracks, and even fossilized feces and vomit.• majority of fossils are remains of the hard parts of

organisms.

Evolution

How do fossils form?

• Fossils form when body parts or impressions are buried in rock before they decompose and preserved through geochemical processes.

• not usually the actual bodily remains.• extremely rare event, so most organisms not preserved

Evolution

Archaeopteryx/Modern bird

Homo Erectus

Homo Sapiens

How are extinct fossils that resemble modern species related to them??

Science Questions?

Evolution Is this a fossil link?

Evolution

Science Questions?

How do we account for the geographical distribution of animals so alike yet different?

Ostrich Emu RheaAfrica Australia S. America

Evolution Science Questions?

Why does there appear to be a progression from simple to complex fossils over time?

Why are there no or simpler species in the oldest layers?Why do vertebrates appear only in more recent layers? Why are species in closer layers more similar?

Evolution

How do we account for the evidence that the earth is billions of years old and species have come and gone, spread and changed, have dramatic similarities and amazing differences?

How are all living things so fundamentally alike, yet so diverse??

THE BIG QUESTION?

Evolution

The Answer = Evolution.

1. Living things are similar because they are related; share a common ancestor.

2. Distribution is dependent on geological forces (Plate tectonics and continental drift).

3. Living things are diverse because species have changed in different ways over time.

HOW? WHY?Evolution was an idea without a process.

Evolution

Checkpoint

1. What is Lamarck’s Theory of Acquired Characteristics?

2. How did Malthus influence Darwin?

41ANY QUESTIONS?

Evolution

Interest Grabber

• A Trip Around the World

• While on his voyage around the world aboard the H.M.S. Beagle, Charles Darwin spent about one month observing life on the Galápagos Islands. There, he encountered some unique animals, such as finches and tortoises.

1. On a sheet of paper, list five animals that you have encountered in the past two days.

2. How do these animals differ from the finches and tortoises of the Galápagos Islands? (Examine Figures 15–3 and 15–4 in yourtextbook.)

3. Propose a hypothesis to account for the differences between the animals that you observed and the finches and tortoises of the Galápagos Islands.

Evolution

Section Outline

The Puzzle of Life’s DiversityA. Voyage of the BeagleB. Darwin’s Observations

1. Patterns of Diversity2. Living Organisms and Fossils3. The Galápagos Islands

C.The Journey Home

Section 15-1

Evolution

KEY CONCEPT Darwin’s voyage provided insight on evolution.

Evolution

Section 15-1

Figure 15–1 Darwin’s Voyage

Evolution

Charles Darwin and the Theory of Natural Selection

• Darwin's Beliefs BEFORE his voyage on the HMS Beagle

• Father wanted him to be a doctor or a minister• Earth was about 7,000 years old

• Organisms had appeared on Earth in their original

created state• Earth has remained the same except for the effects

of floods or other natural catastrophes• Studied breeding of racing pigeons and dogs : Man

chooses traits that you want in the offspring = selective breeding by man

Evolution The Voyage of the Beagle

Darwin began is famous work during the voyage of the HMS Beagle 1831, as the ship’s naturalist.

Around the world for 5 years.

read geologists, Hutton and Lyell: argued that the earth was 1) millions of years old, 2) historically shaped by the same processes of today, & 3) slow to change

Evolution

Notes from the voyage:

1. Much more diversity than we thought!

2. Species in similar environments often have similar traits or adaptations, even if different locations.

Evolution Notes from the voyage:

3. Related species vary in the same location

4. Some living species seem related to fossils.

Darwin’s Finches

Evolution

Darwin's Voyage on the HMS Beagle (1831-36)

• Discovered the fossil of glyptodon which resembled but were not identical to same animal currently living in area (armadillo).

• ** Galapagos Islands - plants and animals resembled those of the nearby South American coast instead of plants and animals of similar islands in the world –If the organisms arrived from South America and THEN the organisms changed over time : Darwin called this concept: Descent with modification (evolution)

Evolution

Darwin observed differences among island species.

• **Variation is a difference in a physical trait among the same species. (Different species = Interspecific Variation)– Galápagos tortoises that live in areas with tall plants

have long necks and legs.– Galápagos finches that live in areas with hard-shelled

nuts have strong beaks.

Evolution

Pinta IslandIntermediate shell

Pinta

Isabela IslandDome-shaped shell

Hood IslandSaddle-backed shellHoodFloreana

Santa Fe

Santa Cruz

James

Marchena

Fernandina

Isabela

Tower

**Giant Tortoises of the Galápagos Islands

Section 15-1

Evolution

• **An adaptation is a feature that allows an organism to better survive in its environment.

– Species are able to adapt to their environment.

– Adaptations can lead to genetic change in a population.

Evolution

• Darwin found fossils of extinct animals that resemble modern animals.

• Darwin found fossil shells high up in the Andes mountains.

**Darwin observed fossil and geologic evidence supporting an ancient Earth.

Evolution

• **He saw land move from underwater to above sea level due to an earthquake.

• Darwin extended his observations to the evolution of organisms.

• Sea level fossils in the Andes mountains

Evolution

What four conclusions did Darwin draw from his observations during the voyage of the Beagle?

Checkpoint

Evolution

Interest Grabber

• When Is a Flipper a Wing?

• All living things are related. Some relationships are easy to see—your pet cat may not roar like a lion, but it clearly resembles one.Other relationships are less obvious.

Section 15-3

Evolution

Interest Grabber continued

• 1. On a sheet of paper, construct a table that has five columns and six rows. In the columns, write the following heads: Animal Group, Example, Legs, Fins, and Tail. Then, place the following animal groups in their own row: Mammal, Bird, Fish, Amphibian, Reptile, and Insect.

• 2. Give one example for each group, and then fill in the informationfor that example. For Legs, write in the number of legs that eachanimal has. Do animals with fins have legs? Do animals with wingshave legs? If so, how many?

• 3. Can you tell from your table if a fish is more closely related to a birdor to an amphibian? Explain your answer.

Section 15-3

Evolution

Section Outline

Darwin Presents His CaseA. Publication of On the Origin of SpeciesB. Natural Variation and Artificial SelectionC. Evolution by Natural Selection

1. The Struggle for Existence2. Survival of the Fittest3. Descent With Modification

D. Evidence of Evolution1. The Fossil Record2. Geographic Distribution of Living Species3. Homologous Body Structures4. Similarities in Early Development

E. Summary of Darwin’s Theory

Section 15-3

Evolution

Origin of Species, 1859

one of the most important books of the 19th century

“..a theory of descent with modification through variation and

natural selection.”

Evolution Summary

• Darwin did not introduce the idea of evolution; rather, he proposed the theory of Natural Selection and descent with modification.

• Darwin did not claim that humans came from apes; rather, he theorized that all species may have come from earlier prototypes, perhaps from one single prototype.

• His theory has profoundly affected the way we think about science and nature.

• For over a century, his basic claims have been supported by scientific studies.

Evolution

Natural Variation

Differences among individuals of a species

Interspecific Variation

Differences among members of different species

Artificial Selection

Selection for breeding of useful traits from natural variation among different organisms

Struggle for existence

Competition between same species for food, shelter, etc.

**Fitness

Ability of an organism to survive and reproduce.

Adaptation

Inherited characteristic that increases the chance for survival

Evolution

**HeritabilityThe ability of a trait to be passed sown from one generation to the

next.Survival of the fittest

The best suited to an environment will survive and reproduceNatural Selection

The individual that can survive and reproduceDescent with modification

All organisms have descended from another organism with changes

Common descentAll living things have a common ancestor

Homologous structureStructures that have different mature forms but develop from the same embryonic tissue

Evolution

KEY DEFINITIONS**Population

Group of individuals of the SAME SPECIES, living in the SAME AREA at the SAME TIME, and able to breed with one another

EX: Humans in Idaho Falls

Evolution

change (MUTATION) that results in

a species being better suited to its environment

Variation = appearance of an inherited trait that makes

an individual different from other members of the population.

Variations in individuals may eventually lead to a NEW Species

Evolution

KEY CONCEPT Darwin proposed natural selection as a mechanism for evolution.

Evolution

**Mechanism of evolution•Species change over time because the environment changes and selects FOR individuals that are better adapted (possess favorable traits) leading to more future members having those traits.

•The traits must be heritable to be passed on to offspring.

•The traits must make the individual more successful and able to reproduce.

Natural Selection

Evolution

Variations may include:

1) Make up

2) Taste

3) Spit Venom

4) Poisonous

EXAMPLE: Desert plants have evolved a thick waxy cuticle (skin) and needlelike leaves.

HOW are these adaptations important to its survival?

13.1 Ecologists Study Relationships

A. Principles of Natural Selection

1. **Resources are limited so not all individuals survive. (Malthus)

2. Individuals are genetically variable ( have different in traits due to mutation, sexual reproduction, etc. that can be inherited).

3. Favorable traits increase chances of survival & reproduction = more offspring contributed to next generation.

4. More members in successive generations will possess the favorable trait (genes).

Evolution

Evolution

Evolution

Evolution

Darwin's Theory of Natural Selection

1) Nature selects organisms with traits

2) Individuals with traits most favorable to a specific environment reproduce and pass these traits on to their offspring >MOST favorable TRAITS INCREASE in a population over time

3) Organisms produce more offspring than the environment can support

SELECTIVE PRESSURE = competition constantly

presents challenges to a species or individual's survival

Evolution

Several key insights led to Darwin’s idea for natural selection.

• Darwin noticed a lot of variation in domesticated plants and animals.

• Artificial selection is the process by which humans select traits through breeding. Hybridization had changed plants from their original shape and size.

neck feathers

crop

tail feathers

Evolution

• There are four main principles to the theory of natural selection.– variation

Natural selection explains how evolution can occur.

– overproduction– adaptation– descent with modification

Evolution

• **Fitness is the measure of survival ability and ability to produce more offspring.

ADAPTATION OVERPRODUCTION

VARIATION

Evolution

Survival of the Fittest Microevolution = small change (mutations)

that occurs in an organism may lead to NEW SPECIES

Examples:

brocolli, cabbage, brussel sprouts, and cauliflower are same species but developed through selective breeding

Hawaiian silversword

When the individuals of two populations can no longer

interbreed, the two populations are considered to be

different species.

Evolution

• Natural selection can act only on traits that already exist.• Structures take on new functions in addition to their

original function.

Natural selection acts on existing variation.

wrist bone

five digits

Evolution

Darwin proposed that species present on earth had come from a common ancestor, & through a series of selected adaptations over millions of years, had diverged into the species present today.

Descent With Modification

Evolution

A. New species arise from previous species through a series of adaptations selected for over time (also called Macroevolution)

B. Species share common ancestry

Descent With Modification

Australopithecus Homo erectus Homo sapien

Evolution

Checkpoint

1. What are the four conditions of natural selection?

2. What the struggle for existence?

3. What is survival of the fittest?

4. Does natural selection give organisms what they need to survive?

80ANY QUESTIONS?

Evolution

KEY CONCEPT Evidence of common ancestry among species comes from many sources.

Evolution

Evidence for evolution in Darwin’s time came from several sources.

• Fossils provide evidence of evolution.

• **Fossils in older layers are more primitive than those in the upper layers.

Evolution

Beaver

NORTH AMERICA

Muskrat

Capybara SOUTH AMERICA

Coypu

Figure 15–14 Geographic Distributionof Living Species

Beaver

Muskrat

Beaver andMuskrat

Coypu

Capybara

Coypu andCapybara

Evolution

• **The study of geography provides evidence of evolution.

– island species most closely resemble nearest mainland species

– populations can show variation from one island to another

Evolution

• **Embryology provides evidence of evolution.

Larva

Adult barnacleAdult crab

– identical larvae, different adult body forms– similar embryos, diverse organisms

Evolution

• The study of anatomy provides evidence of evolution.

Human hand Bat wingMole foot

– **Homologous structures are similar in structure but different in function.

– Homologous structures are evidence of a common ancestor.

Evolution

**Comparative Anatomy

Humerus

Forearm

Carpals

Digits

Evolution

Turtle Alligator Bird Mammals

Typical primitive fish

Figure 15–15 Homologous Body Structures

Evolution

Human hand

Bat wing

Mole foot

Fly wing

– Analogous structures are not evidence of a common ancestor.

• The study of anatomy provides evidence of evolution.

– **Analogous structures have a similar function.

Evolution

Concept MapSection 15-3

includes

Evidence of Evolution

Physical remains of organisms

Common ancestral species

Similar genes Similar genes

which is composed of which indicates which implies which implies

The fossil recordGeographic

distribution of living species

Homologous body structures

Similaritiesin early

development

Evolution

Macroevolution big change among species over time:leads to large scale evolutionary changes.Example: replacement of dinosaurs by mammalsExtinction species disappears forever (climate,natural disaster, man)Summary of Modern Theory of Evolution: Mutation

leads to new species , which over time, leads to natural selection, the replacement of species by other species.

Vestigial organOrgan that serves no function in an organism

Evolution

• **Vestigial structures are remnants of organs or structures that had a function in an early ancestor.

• Ostrich wings are examples of vestigial structures.

Structural patterns are clues to the history of a species.

Evolution

KEY CONCEPT New technology is furthering our understanding of evolution.

Evolution

Fossils provide a record of evolution.

• Paleontology is the study of fossils or extinct organisms.

Evolution

• Paleontology provides evidence to support evolution.