Species Change Over Time

Lamarck Darwin

Who thought this? There is VARIATION within a

species DARWIN

Organisms can make a change to themselves and pass that onto their offspring LAMARCK

Change within a population, not an individual DARWIN

Natural Selection DARWIN

Acquired Characteristics LAMARCK

Organisms change over time. BOTH

Species cannot go extinct Lamarck

Whose idea is still believed by the scientific community today Darwin

Adaptations Over Time

Chapter 12 Pages 334-341

Review of Important Terms to Know

Traits-characteristics of a species that are passed from parent to offspring.

Offspring- the scientific name for “babies” of an organism

SpeciesSpecies- a group

similar organisms that can mate with each other and produce fertile offspring

Fertile- the ability to reproduce

~8.7 Million Species Worldwide!

Animals: 7.77 million Fungi: 0.61 million Plants: 0.30 million Protozoa: 0.04 million Chromists: 0.03

million

VariationVariation- any

inherited difference between members of the same species

Ex: albino squirrel, the ability for baby turtles to swim faster, a longer neck, wider nostrils, thicker fur…

Forsten’s Tortoise

What Causes Variation? SEXUAL REPRODUCTION Variations result from

permanent changes in an organism’s genes.

The permanent changes in the genes are called MUTATIONS.

American Alligator with a pigment mutation

Mutations…Good or Bad???

Mutations can be either beneficial, harmful or neutral.

Some gene changes produce LARGE variations. Ex: Albino squirrel

Some gene changes produce small variations Ex: shape of human

hairlines

“People don't realize it, but everyone has about 60 genetic mutations in their body at any given time. (Tudge, Colin)”

King Cheetah Pattern Mutation “A genetic mutation

changes a spotted cheetah pattern to a striped king cheetah pattern.”

Adaptation Adaptation- a variation

(or trait) that helps an organism survive & reproduce

Adaptations can be behavioral or physical.

AdaptationsBEHAVIORAL

The way an organism acts or behaves

Migration Hibernation Communication Mating dances

PHYSICAL Body structures

Camouflage Shapes of beaks Fur Blubber Color or Markings Webbed-feet Body coverings

4 Principles of Natural Selection

Darwin’s Theory of Natural Selection

Natural Selection- individuals that are better adapted to their environment are more likely to survive & reproduce than other members of the same species

Also known as “Survival of the Fittest”

Overproduction 1) Overproduction-

producing more offspring than can survive

Overproduction

Competition2) Competition-

individuals compete for food, nesting sites, territory, & other resources that affect their ability to reproduce

Variation3) Variations- a

difference between members of same species that may help it survive and reproduce

Some are born with an advantage over the others!

Ex: beak shape, eyesight, height, speed…

Selection 4) Selection- over time,

the environment “selects” organisms w/ helpful traits to be parents of next generation

Ex: Just as the changing forest affected the peppered moths.

.

WRAP UP

Over a long period of time, natural selection can lead to the evolving of a new species. Helpful variations remain & unfavorable ones disappear

Factors that Affect Natural Selection

1) Overproduction- producing more offspring than can survive

2) Competition- offspring compete for food & other resources

3) Variations- a difference between members of same species that may help it survive

4) Selection- over time, the environment “selects” organisms w/ helpful traits to be parents of next generation

Do Now: Bear Trio! In your journal answer

the following questions.

What differences do you notice among the three bears?

What did Darwin call these differences?

What causes these differences among organisms?

Line Graphs Which day were the most

cookies sold? What is the title of

graph? What day were 20

cookies sold? About how many cookies

were sold on Tuesday?