Darwin's TheoryDarwin's Theory

Ch 7 sec 1Ch 7 sec 1

GOAL/PURPOSEGOAL/PURPOSE

TO LEARN WHAT FACTORS TO LEARN WHAT FACTORS CAUSE EVOLUTION AND THE CAUSE EVOLUTION AND THE

DIVERSITY OF LIFE ON PLANET DIVERSITY OF LIFE ON PLANET EARTHEARTH

Darwin's ObservationsDarwin's Observations

• Who was Charles Darwin?• http://www.brainpop.com/science/famouss

cientists/charlesdarwin/• KEY- Darwin’s important observations

included the – • the diversity of organisms• the remains of ancient organisms• the characteristics of organisms on the

Galapagos Islands

DiversityDiversity

• Diversity- The number and variety of species present in an area and their spatial distribution.

• KEY- Darwin was amazed by the tremendous diversity of the living organisms that he saw. Ex insects that looked like plants and vice versa.

• http://footage.shutterstock.com/clip-180478-stock-footage-leaf-mimic-mantis-on-heliconia-plant-in-the-rainforest-understory.html

SpeciesSpecies

• Species- ARE group of similar organisms that can mate with each other and produce fertile offspring

• http://www.google.com/search?q=liger&hl=en&safe=active&client=firefox-a&hs=K5v&rls=org.mozilla:en-US:official&ie=UTF-8&oe=UTF-8&prmd=ivns&source=lnms&tbm=isch&sa=X&ei=QTJjUNLbDq7ligLC14DgDQ&ved=0CAcQ_AUoAQ

• How many different species do you think have been identified on earth?• Key- The National Science Foundation’s “Tree of Life” project

estimates that there could be anywhere from 5 million to as many as 100 million species on the planet, but science has only identified about 1.5 million.

• FOSSILS- are the preserved remains or traces of an organism that lived in the past

• `

Fossils cont’dFossils cont’d

ADAPTATIONSADAPTATIONS

• ADAPTATIONS- ARE A TRAIT THAT HELPS AN ORGANISM SURVIVE AND REPRODUCE IN ITS ENVIRONMENT

• KEY- DARWIN REASONED THAT PLANTS OR ANIMALS ARRIVED ON THE GALAPAGOS ISLANDS FACED ENVIRONMENTAL FACTORS THAT WERE DIFFERENT FROM THOSE ON THE MAINLAND.

EVOLUTIONEVOLUTION

• KEY- DARWIN HYPOTHESIZED, THAT SPECIES GRADUALLY CHANGED OVER MANY GENERATIONS AND BECAME BETTER ADAPTED TO THE NEW ENVIRONMENT.

• EVOLUTION- IS THE GRADUAL CHANGE IN A SPECIES OVER TIME

EVOLUTION AS A SCIENTIFIC EVOLUTION AS A SCIENTIFIC THEORYTHEORY

• SCIENTIFIC THEORY- IS A WELL TESTED CONCEPT THAT EXPLAINS A WIDE RANGE OF OBSERVATIONS- EVOLUTION

• NATURAL SELECTION- INDIVIDUALS THAT ARE BETTER ADAPTED TO THEIR ENVIRONMENT ARE MORE LIKELY TO SURVIVE AND REPRODUCE THAN OTHER MEMBERS OF THE SAME SPECIES

NATURAL SELECTIONNATURAL SELECTION

• http://www.brainpop.com/science/ecologyandbehavior/naturalselection/

• VARIATIONS- ARE DIFFERENCES BETWEEN INDIVIDUALS OF THE SAME SPECIES OTHERWISE CALLED “GENETIC VARIATIONS”.

• EX- CERTAIN INSECTS MAY BE ABLE TO EAT FOODS THAT OTHER INSECTS OF THE SAME SPECIES AVOID. THEY HAVE AN ADVANTAGE

COMPETITION AND COMPETITION AND SELECTIONSELECTION

• KEY- DARWIN PROPOSED THAT, OVER A LONG TIME, NATURAL SELECTION CAN LEAD TO CHANGE.

• KEY- HELPFUL VARIATIONS MAY GRADUALLY ACCUMULATE IN A SPECIES, WHILE UNFAVORABLE ONES MAY DISAPPEAR.

Why?Why?

USE THE TEXT BOOK TO ANSWER THE FOLLOWING USE THE TEXT BOOK TO ANSWER THE FOLLOWING QUESTIONS WRITE THE Q AND AQUESTIONS WRITE THE Q AND A

• 1. WHAT IS AN ADAPTATION? WHAT WERE THE DIFFERENCES IN THE FINCHES BEAKS?

• 2. WHAT IS SELECTIVE BREEDING?• 3. WHAT IS A VARIATION? GIVE AN

EXAMPLE.• 4. WHAT IS NATURAL SELECTION? GIVE

AND EXAMPLE• 5. DESCRIBE HOW TURTLES SURVIVE

USING COMPETITION AND SELECTION

GREAT DISCOVERIES WITH BILL GREAT DISCOVERIES WITH BILL NYENYE

• http://app.discoveryeducation.com/search