200 likes | 315 Vues
Chapter 3, Lesson 3. How Do New Species Evolve?. Charles Darwin. Naturalist - studies nature His job was to collect and describe as many different species as possible 1835- His belief was that a species didn’t change. . Charles Darwin. He sailed the HMS Beagle 1831-1835
E N D
Chapter 3, Lesson 3 How Do New Species Evolve?
Charles Darwin • Naturalist- studies nature • His job was to collect and describe as many different species as possible • 1835- His belief was that a species didn’t change.
Charles Darwin • He sailed the HMS Beagle 1831-1835 • In 1835 he reached the Galapagos Islands • Stayed about 5 weeks visiting some of the islands • Islands were in natural state– few people
Charles Darwin • There he made many observations by studying: *topography *landscapes * specimens of plants, animals • His observations changed his view on species
Tortoises • Darwin was able to tell where a species came from based on its appearance -Islands with a lot of vegetation and grass *Structural adaptation - larger - rounded, dome shell - short legs/necks
Tortoises • Islands with little vegetation and grass *Structural adaptation - smaller - longer legs - smaller shell with curved up front edge
Finches • Observed 13 different species of finches • Different beaks based on the food they ate - long or short beaks
Natural Selection • Darwin spent the next 20 years studying his observations • He came up with the Theory of Natural Selection *The idea that organisms that best adapted to their environment will be the ones most likely to survive and reproduce.
Natural Selection • 4 main points to Darwin’s theory 1) Organisms usually produce more offspring than can survive. Example: frog eggs
Natural Selection 2) Competition often exists between male mammals to win a mate. The winner will reproduce and pass on their traits. Example: Antelopes fight for a mate.
Natural Selection 3) Organisms best adapted to their environment are the ones most likely to survive. If they survive they are able to reproduce and pass on traits. Example: Peppered Gray moths
Natural Selection 4) Parents pass on their traits. Offspring often looks like parents but variations may occur. Example: Shell variations
Structural Adaptations • Any body parts or coloring that helps an organism survive. • Examples: Cactus, Mole Rat, Peppered Moths
Structural Adaptations • Cactus: Spines= protection Waxy skin= retains water, little evaporation
Structural Adaptations • Mole Rat Larger teeth/claws= tunnel underground Whiskers= feel with them
Structural Adaptations • Peppered Moths -In cities where factories left soot on trees, the moths became darker to blend in.
New Species Over Time • Population- All the members of one species that live in a certain place.