Download Darwin's Theory - Santee School District

Darwin's Theory
Ch 7 sec 1
GOAL/PURPOSE
TO LEARN WHAT FACTORS
CAUSE EVOLUTION AND THE
DIVERSITY OF LIFE ON PLANET
EARTH
Darwin'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
Diversity
• 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-180478stock-footage-leaf-mimic-mantis-on-heliconiaplant-in-the-rainforest-understory.html
Species
• 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=acti
ve&client=firefox-a&hs=K5v&rls=org.mozilla:enUS:official&ie=UTF-8&oe=UTF8&prmd=ivns&source=lnms&tbm=isch&sa=X&ei=QTJjU
NLbDq7ligLC14DgDQ&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’d
ADAPTATIONS
• 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.
EVOLUTION
• 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
THEORY
• SCIENTIFIC THEORY- IS A WELL
TESTED CONCEPT THAT EXPLAINS A WIDE
RANGE OF OBSERVATIONS- EVOLUTION
• NATURAL SELECTIONINDIVIDUALS THAT ARE BETTER ADAPTED
TO THEIR ENVIRONMENT ARE MORE
LIKELY TO SURVIVE AND REPRODUCE
THAN OTHER MEMBERS OF THE SAME
SPECIES
NATURAL SELECTION
• http://www.brainpop.com/science/ecologyandbe
havior/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
SELECTION
• 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?
USE THE TEXT BOOK TO ANSWER THE FOLLOWING
QUESTIONS 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
NYE
• http://app.discoveryeducation.com/search