Do Now: Give me two reasons why you think the population of certain species continue to grow OR are gone after a few generations?

The species that survive is do to adaption & struggle, and the species which overproduce

SWBAT- Discuss how the changing environmental conditions result in evolution

Evolution

What is Evolution?Evolution - how modern day organisms have

changed from ancient organisms.

- gradual “change over time”

Charles DarwinCollected data and

observations to create hypothesis about evolution.

Published On the Origin of Species containing his theory of evolution.

His important observations included the diversity of living things, the remains of organisms

Father of Evolution

Darwin’s ObservationsHe visited many continents while

serving on the ship H.M.S Beagle.

He noticed a great diversity (variety) in organisms (species) on these different continents.

Australia – Kangaroos

Galapagos – Giant Tortoises and Finches

What is you definition of a “species” ?

SWBAT- Discuss how the changing environmental conditions result in evolution

SpeciesSpecies – a group of organisms that can reproduce

and create offspring that can reproduce.

Who Survives?Natural Selection – those individuals who have

favorable variations (from their genes) are able to survive and reproduce successfully.

Conditions for Natural Selection

1. Overproduction – every species produces more individuals than will survive.

Ex: insects, fish, dandelions

2. Struggle for Survival – individuals within a species will compete for resources.

- Ex: environmental conditions: food, space, water, etc.

3. Adaptation (adaptive value) – any genetic trait that helps an organism survive, compete, and reproduce better than others.

- Ex: Grasshoppers with longer legs

Lions with sharper teeth

Where Do Variations Come From?

Genetic variations can only be passed on if they occur in gamete cells.

Sources of variation:

a. Mutation – change in DNA bases.

- Some are “good” and can be passed on.

b. Sexual Reproduction – crossing over of chromosomes and sexual recombination (fertilization) increases variety in offspring.

Mutations occur at random – “good” ones will become popular and passed on.

4. Survival of the Fittest – individuals who have certain variations will be able to survive if environment changes.

- Ex: Disease and resistance/immunity

5. Speciation – those individuals that survived to reproduce, may develop into a new species.

How does it happen?

Reproductive isolation – a population may become separated by a geographical barrier.

- Ex: River, mountain range, earthquake, ocean

Many new species of finches develop from isolation.

Differences in beak sizes/shapes result from different environments (food sources).

This is the definition of what “condition of natural selection ? “any genetic trait that helps an organism survive, compete, and reproduce better than others.”

Adaptation

SWBAT- Discuss how the changing environmental conditions result in evolution

Examples of Natural Selection

1. Peppered Moth Evolution

Change in moth color from white to black due to change in their environment from white to black.

Black moth color = “favorable” mutation

2. Antibiotic Resistance

Antibiotics – kill bacteria with diseases.

Through natural selection, some bacteria mutate and become resistant (not

affected) to antibiotics.

These resistant bacteria multiply (asexually) and soon become the only bacteria around.

New antibiotics must now be made.

Red Bacteria have mutation for resistance

After Treated with Antibiotic

Only Red Bacteria survive and pass on good mutation

Evidence of Evolution1. Similarities in DNA and Proteins

Proteins from 2 different species may have similar amino acid sequences.

- Ex: Humans and Chimpanzees share same protein for blood which differs by only 1-2 amino acids.

SWBAT determine the factors that effect the evolution of all living things

What are the five parts of “Conditions for Natural Selection”?

Adaption, Struggle for Survival and Overproduction, Speciation and Survival of the fittest

2. Similarities in Embryo Development

Early stages of embryos in many animals is very similar.

- Differentiation happens the same way in many organisms.

- Suggests we come from a common ancestor.

Evidence of Evolution

3. Homologous Body Structures

Similarities in forelimb bones of different animal species: wing of a bat, flipper of a whale, arm of a human.

- Bones are attached in similar places all came from a common ancestor.

Vestigial structures – organs that serve no function in an organism.

- may have been useful in the past.

- Ex: human appendix, leg bones in whale

4. Fossil Record – fossils from different layers of the earth show species have changed over time.

- The earth is approximately 4.7 billion years old.

Origin of LifeFirst organisms were single-celled (bacteria).

As time went on, more complex multicellular organisms developed.

Now, the most complex multicellular organisms (humans) have evolved.

DO NOW:

Who was know for the book “On the Origin of Species” which contained the person’s theory of evolution.

SWBAT determine the factors that effect the evolution of all living things

Extinction Extinction - Disappearance of species from the

earth.

- Species cannot adapt to changing environment.

- Natural disaster (meteor)

- Bottom - Bottom layers=layers=oldeoldest st (simplest)(simplest)

- Top layers - Top layers = = most most recent recent (more (more complex)complex)

Phylogenetic (Family) TreesFamily Tree - Simple diagram used to show

relationships and common ancestors amongst species.

A phylogenetic tree helps to explain the pattern of connection of different groups of species.

Family Tree Vs. Phylogenetic

Punctuated EquilibriumPunctuated Equilibrium – long,

stable periods of equilibrium interrupted by rapid change (due to mutations).

- Different speeds of evolution for different species.

Natural Selection