Transcript Darwin - San Diego Unified School District

Slide 1 - Evolution
Change in species over.
Slide 2
People used to believe:
•Species are designed
by a divine creator (aka
God).
•Are fixed (aka
unchanging). In other
words, species have not
changed over the
years.
•False belief Earth is only
6000 years old. Earth is
actually 4.6 Billion Years
Old.
Slide 3
Charles Darwin came up with the theory of evolution!
He Lived in the 1800s.
.
Slide 4 - Darwin’s Voyage
1831 at age 22
Darwin took a
job as a
naturalist
(Person who
studies nature
such as plants
and animals) on
the English ship
HMS Beagle.
Slide 5 - Darwin’s voyage on the Beagle
He started his trip in England and sailed all over the world.
Slide 6 - Galapagos Islands
He is known for his stop in the Galapagos Islands.
He studied each Island in the chain and found species
were very similar, but unique compared to species in
South America, which is only 500 miles away.
Slide 7 - Galapagos Tortoise
Much bigger than tortoises on South America.
More food in the Islands compared to the mainland.
Slide 8 - Galapagos Iguana
Island Iguanas have claws
Mainland Iguanas don’t have claws.
Claws allow iguanas to grasp onto rocks in the ocean.
Mainland iguanas eat on land.
Slide 9 - Galapagos Finches
Galapagos finches have different beaks than mainland birds,
because they feed on different food.
Slide 10 – Species
Organisms of the same species have:
Similar traits + Reproduce + Produce fertile offspring.
Horse + Donkey = Mule
Mule cannot reproduce
Thus, Horse and Donkey a separate species even though
they can have offspring.
Slide 11
Natural Selection
What causes species to
change (aka evolve)!
Giraffes eat tree leaves.
If short giraffes can’t reach
the leaves, they will starve
and die. Only tall giraffes
will survive to reproduce.
Since they have tall genes,
their offspring will be tall
too. This is what drives
populations to change,
“Survival of the Fittest!
Slide 12
Before the Industrial Revolution
Birds eat Peppered moths.
Before industrial revolution tree had light bark.
Since dark moths stood out, they were eaten by birds.
Light moths population increase!
Dark moths population decreased!
Slide 13
After the Industrial Revolution
Soot and ash pollution from industry covered trees.
Tree bark became darker.
Dark moths no longer stood out, but white moths did!
Light moths population decreased!
Dark moths population increased!
Slide 14 - Evidence of Evolution
 Fossils
 Adaptations
 Anatomy
 Embryology
 Biochemistry
Slide 15 - Fossils
Showed that whale ancestors once lived on land.
Scientists know this because whales still have a hind-leg bone
inside of them which is meant for walking, not swimming!
The hind-leg one currently has no use in the whale!
Slide 16 - Adaptations
Any trait that increases an organisms chances for survival.
Structural
Wax-Coated Leaves
prevents evaporation
Physiological
Evolves RAPIDLY
Slide 17 - Structural Adaptations
 Mimicry
 Camouflage
Slide 18 - Mimicry
Mimic = to copy someone
When one species resembles another species.
Slide 19 - Camouflage
Matching in color with surroundings!
Slide 20 - Anatomy
 Homologous Structures
 Analogous Structures
 Vestigial Structures
Slide 21 - Homologous Structures
Homo = Same
Same structures between species.
Come from common ancestor!
Slide 22 - Analogous Structures
Bird and Bugs both fly, but wings are a different structure.
Bird Wings = Bone (mainly proteins)
Bug Wings = Chitin (mainly carbohydrates)
Slide 23
Homology Versus Analogy
Slide 24 - Vestigial Structure
A body structure in a present-day organism
that no longer serves its original purpose, but
was probably useful to an ancestor.
Whale ancestors lived on land and walked, so they needed a
hind-leg bone.
Whales still have this structure inside of them, but don’t use it
because they live in the ocean now and swim.
Slide 25 – Human Vestigial Organ
Appendix
Slide 26
Vestigial Structure Examples:
Mole Rat
Eyes
Ostrich
Wings
Slide 27 – Embryo
The first stage of development.
Slide 28 – Embryology
Compares the embryos of different species.
Scientist have found they look alike.
All have a gill pouch and anal tail.
Slide 29 - Can you tell which will
become a chicken? Cat? Bat?
Snake? Human? Possum?
All look the same.
Slide 30 – Which one is a cat? Can
you tell yet?
Slide 31 – What about now? Which
one will turn into a cat?
All these organisms evolved from the same common ancestor
Slide 33 - Biochemistry
Some organisms have similar DNA sequences.
Slide 34 - For Example:
Versus
Chimpanzee
Gorilla
Slide 35 - For Example:
Versus
Chimpanzee
Rose Bush