chpt5 evolution

L.O: students will review evolution

Do Now: read and highlight

the evolution

review packet!

Things are always changing.

People are always changing

Cities are always changing

fashion changes

Even our footwear changes

Whoof!

GROWL!

Man! My dogs are barking!

Species change too!

Human beings have NO trouble believing that individuals, cities and fashions change over

time…..but for most of human history, people didn’t think that whole species could change over time.

Even today, some still don’t believe this!

Yes! Yes!

Yes! NO!

WHY?

WHY?BECAUSE OF

“TIME”!

we can SEE cities change in our lifetimes….

we can SEE fashions change in our lifetimes….I used to

like classical things.

Now I’m only into

GOTH!

we can SEE people change in our lifetimes….

Because of the time intervals needed for evolutionary change, (thousands of years,

millions of years, billions of years) for most of human history, people had no idea that species

could evolve.

For most of human history, people thought that living things were ALWAYS the same way they appear NOW!

They were wrong!

The pioneering work of Charles Darwin gave science a precise explanation of how living things evolve over a long period of time…..

AFTER Darwin, countless pieces of molecular, physical and behavioral evidence have

corroborated Darwin’s theories and proven that living things DO evolve.

Evolution is: change over time.

Earth is 4.5 billions of years old-plenty of time for evolution to

happen

Evolutionary trees:

EVOLUTIONARY TREES:• Evolutionary trees: are diagrams

that show the evolutionary pathways a group of species have followed.

• They show the ancestors.• they show the current species that

evolved FROM the ancestors.• They show the common ancestry.• They show which species are more

closely related and which are not closely related.

• They show the extinct species and the still alive species.

How to read an evolutionary tree diagram:

• Species A is the common ancestor of all the other species.(all branches lead to it)

• Species D, E and F are all extinct (their branches stop in the past).

• Species B and C are extant (still alive in the present)( their branches reach into the present)

• Species E and F are more closely related to each other than to species D. (E & F on the same branch, D is on a different branch)

Some typical evolution tree diagram questions:

Which species the common ancestor of all the other species?

A is the common ancestor of all the other species. All the branches lead back to it.

Name the 6 species that are now extinct. SUPPORT your answer.

C, D, H, L, O and P are all extinct. we know they are extinct because the tree diagrams show their

branches ending in the past.

When did species L go extinct?

~30 million years ago.

Which species are still alive? SUPPORT your answer.

J, K & M, are still alive, because the diagram shows them in the present time.

Which species is the common ancestor of J and K?

I is the common ancestor J & K branch from it.

Which species are the most closely related O & P or O AND H? SUPPORT your answer.

O & P are more related to each other because they’re on the same branch.

Which species has the most similar DNA to species J? support your answer.

Species J & K have the most similar DNA. They’re on the same branch.

The following are some evolutionary tree diagrams from past regents.

What is a “fossil”?

What is a “fossil”?

FOSSILS ARE THE REMAINS OR TRACES OF AN ORGANISM THAT WAS ONCE LIVING.

Now answer 1-27.

THE THEORY OF EVOLUTION:

Charles Darwin devised the theory of Natural Selection (the theory of evolution):

The theory of natural selection says four things:

1. There are many many variations in populations.

2. Populations always overproduce offspring.

3. Organisms compete for the limited resources

4. Organisms with an advantage tend to win competitions and have more offspring

1. There are many, many, many variations in populations of organisms

2. organisms always overproduce offspring. They have more offspring than the environment’s limited resources can support.

3. Because resources are limited, Individuals will Compete for limited

resources.

MINE! NO MINE!

MINE!NO

MINE!

OURS!

NO OURS!

Mine!

No mine!

4. Organisms with advantages win competitions and have more offspring

THE WINNER!

I took this away from another bird

just for you! Will you marry me?

You’re a good “breadwinner”.

Yes I’ll marry you!

I hope our offspring

come out just like you!

Overtime, the small changes of natural selection lead to the big changes of evolution.

EVOLUTION IN A CHANGING ENVIRONMENT:

Species walk a tightrope through life…SURROUNDED by danger!

Species try to find food…Hey Paul,

do you hear something?

You’re ALWAYS hearing

“something”. Eat some of

this delicious grass and

stop worrying so

much!

Finally some

“grub”

Yeah! I’m so hungry, I can eat a horse!

And species try NOT to BECOME

food!

Paul! Wait for me!

I’m out of

here!

Who “wasted” their money on

a bike now?

Living things are in a constant fight; competing for mates, TERRITORY, hierarchical position and hoping they don’t LOSE!

1..2..3..

Why do I see

stars?

The habitat, the niche, the

cheese and Minnie Mouse

are MINE!!!

SEXUAL REPRODUCTION: THE SOURCE OF

EARTH’S BIODIVERSITY.

Every individual born through sexual reproduction is a unique and born with

a unique mixture traits.

During CROSSING OVER ( meiosis) and GENE RECOMBINATION ( fertilization); a different & unique combination of genes (and traits) is produced every time organisms reproduce sexually.

My momma said:Sexual reproduction is

like a box of chocolates, you don’t know what

you’re gonna get.

Sexual reproduction could produce an organism that is sweeter than others….

Sexual reproduction could produce an organism with a harder shell….

Sexual reproduction could even produce an organism with a stronger immune system against new diseases!

If the organism’s traits help it to survive and produce offspring then it is “FIT”!

Survival of the fittest means the one BEST able to cope with environmental change!

Example: in “I am Legend”, these characters were “fit” because they were immune to the Crippen Virus! They

survived while all the “unfit’ died out.

Now answer 28- 57.

GEOGRAPHIC ISOLATION BRINGS ABOUT EVOLUTION:

Coping with a changing environment leads to evolution.

Geographic isolation

• Geographic isolation is when different members of a species become isolated (separated) by oceans or mountains etc.

• They are in different environments, having different foods, facing different dangers.

• Having to cope with different environments they may drive them to become different species.

Example: geographic isolation has turned the African and Asian elephants into different species. WHY?

DARWIN’S FINCHES:

These are the Galapagos Islands. Darwin spent a few weeks studying the isolated organisms there.

Darwin’s observations of especially the FINCHES led to his theory of natural selection (evolution).

These are Darwin’s finches.

finches on each of the different islands that were similar but had different beaks and ate different foods..

Darwin hypothesized the different types of foods on the different islands and the

geographic isolation “SELECTED” the bird with the “FITTEST” beak to survive on a

particular island.

the finches that could NOT adapt to the food on an island died out.

you WILL see this chart on the regents exam. You MUST know how to interpret it!

the outer circle shows the finch’s bill and its name.

the next two inner circles describe the type of bill.

the innermost circle shows the type of food the finch eats.

what kind of bill does the large ground finch have and what type of food does it eat?

why is the small ground finch able to share an island with the woodpecker finch?

What would happen to the warbler finch if all the animals died on its island?

Now answer 58-81.

THE CAUSES OF VARIATIONS

AND THE CAUSES OF

EVOLUTION:

Three things lead to variations and eventually to evolution:

1. Mutations2. Crossing over during meiosis3. Gene recombination

1.MUTATIONS: are changes in DNA. If the mutation happens in the gametes, it can be passed on.

father

daughter

father

son

If superheroes existed, their powers could ONLY be passed to offspring though their gametes!

father

daughter

father

son

Environmental stresses like increased exposure to radiation can lead to more mutations and increased rates evolution

Increased rate of evolution

2. Crossing over during meiosis reshuffles genes producing unique gametes.

3.GENE RECOMBINATION: during fertilization a random unique sperm cell fertilizes a random unique ovum producing a random

unique person!

Note: in asexual reproduction there is very little genetic variation (and evolution can be slower to

happen) because one parent is producing genetically identical offspring.

Note: in asexual reproduction, evolution can be slower to happen because mutations are the

ONLY source of genetic variations.

Evolutionary change:

Over time, all the gene reshufflings in sexual reproduction and gene mutations can lead to

evolutionary change.

Evolution can be a change in structure, function or behavior.

Structural change: similar body parts (similar bones) showing evolution from a common ancestor.

similar bones showing evolution from a common ancestry

similar bones showing evolution from a common ancestry

similar bones showing evolution from a common ancestry

similar bones showing evolution from a common ancestry

similar body parts showing evolution from a common ancestry

Now answer 82- 94.

Evidence of evolution

antibiotic-resistant bacteria, pesticide-resistant insects.

Some bacteria are pathogens (cause diseases)

Antibiotics are cures that kill bacteria

Most bacteria are killed by antibiotics, but some bacteria are evolving resistance.

Darwinian evolution: bacteria-style!

Genetic variations exist in the bacteria population.

The environment changes (antibiotics are introduced)

The unfit die. The fittest survive.

The fittest pass their successful genes to their offspring

The antibiotics has “forced” the non-resistant bacteria population to evolve into a drug-

resistant population!

Darwinian evolution: insect-style

Variations exist in an insect population, some are pesticide-resistant, but most are non-resistant.

The environment changes. humans spray pesticides (bug spray)….

Many of the non- resistant are unfit & die. The pesticide-resistant are fit and insects live to have babies.

After several generations, the insect population has evolved due to the pesticide spraying.

Now answer 95- 101.

Faster or slower evolution

Some people don’t believe in evolution (especially human evolution) because they

don’t see organisms changing before their eyes!IF

evolution is true,

why don’t I see

monkeys turn into people,

huh?

One could NOT see human evolution because we are very long-lived & take a long time to

reproduce! Evolution in us is slow & takes many, many, many, many, many, generations for the

changes to be apparent.

Pesticide-resistant Insects and antibiotic-resistant bacteria offer

conclusive proof of evolution.

Insects have a short reproductive cycle (many generations in a short time) bacteria reproduce every twenty minutes. One bacteria can become millions in

a few days.

We can SEE insects and especially bacteria evolve almost in front of our eyes…and this is a

threat to humans

Pesticide-resistant insects threaten our crops. Antibiotic-resistant bacteria threaten our health!

Our turn to spray YOU humans!

This is MRSA, the

Flesh-eatingBacteria. It

evolved from

“Staph” and is drug-

resistant!

Extinction: when a whole species is no longer alive.

• Species go extinct all the time.• Scientists estimate that 99% of all life that has

lived on Earth is now extinct!

Why do some species go extinct and other don’t?

Variations!

Variations help organisms to adapt to environmental changes.

• Organisms with few variations may face extinction if the environment changes.

• Organisms with many many variations have a better chance to cope with environmental changes.

Ex. Koala bears live on one continent and only eat one kind of plant. If there habitat were destroyed, they would

face extinction.

Humans eat anything, live anyway, do any job. They have so many many varieties of survival strategies.

And now your independent work: complete all the even questions in the packet.

Miss K, Mr. G or Mr. E will do the odd ones!

NOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!

NOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!NOOOOOOOOOO!!!!!!!

!!!!!!!!!!!!!!!