Evolution is the process by which Populations accumulate inherited changes over time.
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Transcript of Evolution is the process by which Populations accumulate inherited changes over time.
Evolution is the process
by which Populationsaccumulate
inherited changes over time.
Includes three major ideas:
Theory of Evolution
All organisms developed from a single life form that lived on Earth billions of years ago.
All organisms share common ancestors.
All species arise from other species.
Scientist have found evidence that allorganisms on earth share a commonancestor…all organisms are related.
Similar bone structure in the
upper arm suggests these animals have a
common ancestor.
Common Ancestor
Mutations Natural
Selection
Two processes are necessary for populations to change over time.
Mutations are sudden changes in the DNA of a gene. These changes can be passed on from parent to offspring.
Some mutations are helpful. Some mutations are harmful. Some are neither helpful or harmful.
Mercury-Poisoning Mutation
Harmful: Albinism is an inherited mutation.
Albinos lack protective skin pigments therefore are prone to skin cancer and do not see well in
bright light.
Helpful: such as a mutation that causes
bright color patterns in flower petals…all the
better to attract pollinating insects.
Mutation
Finches from the Galápagos Islands
H.M.S. Beagle
Five year voyage of H.M.S. Beagle (1831-
1836)
In 1831 Charles Darwin (22 years old) voyaged on the HMS Beagle
to the Galapagos Islands where he made many observationsabout the different species of plants and animals.He was most interested in the birds that livedin the different Islands. In 1859 he wrote a bookcalled “On the Origin of Species”. In it Darwinpresented his theory of evolution by natural selection.
Charles Darwin
“Survival of the Fittest” Traits are selected Traits must be passed from one generation to the
next Changes occur in response to the environment
Natural selection is a process in which organisms
that are better able to survive and reproduce in an environment are more likely to pass their
traits on to future generations.
Natural Selection
An adaptation is a characteristic or trait that helps an organism survive in its environment.
Adaptation plays a major role in natural selection.
An adaptation makes an organism more suited to its environment, and therefore more likely to survive and pass on its traits to the next generation.
Adaptation
Some adaptations are body parts. Other adaptations are behaviors.
A tiger’s teeth are adapted for tearing and chewing. A tiger’s fur
helps it blend into tall grasses.
Feathers are adaptations used for flight. A bird’s beak is adapted to
the food it eats. What type of food do you think this bird eats?
Adaptations
Leaves of green plants are adapted to absorb sunlight. Flowers are
adaptations that attract insects that can help a plant reproduce. How do
you think a plant’s stem helps it survive?
A cactus is adapted to life in a desert. Its thick stems store water. A waxy coating on the
plant reduces water loss.
Adaptations Cont.
A sea turtle retreats into its shell when it senses danger. What are
some other adaptations of sea turtles?
A dandelion’s seeds are easily dispersed
by the wind. How do you think this adaptation help the plant’s species?
How do you think this insect adapted to
living in or near trees?
Adaptations Cont.
Peppered MothsThe European peppered moth often rests on the trunk of trees and is found in two colors: one light and one dark. Before 1850, most peppered moths were light. After 1850, industry created pollution that blackened the tree trunks. Light moths became rare, while the once-rare dark peppered moths became more common.
Which moths are better adapted to the tree that they are on?
Adaptations of Peppered Moths
The light variety of the peppered moth
on a birch tree trunk.
The dark variety of the peppered moth
on a birch tree trunk.
Unpolluted Birch Forest
The light variety of the peppered moth on a soot-blackened tree
trunk.
The dark variety of the peppered moth on a soot-blackened tree
trunk.
Polluted Birch Forest
Evolution Mini Assessment Review
__________ is the process by which populations accumulate inherited __________ over __________.
Evolution changestime
Three Major Ideas of the Theory of Evolution:
Organisms developed from a single life form that lived on Earth billions of years ago.
Organisms share common ancestors. Species arise from other species.
Two processes are necessary for populations to change over time:1. __________ 2. ___________
MutationsNatural Selection
__________ are sudden changes in the ______________ of a gene. These changes can be passed on from parent to offspring.
MutationsDNA
Evolution Mini Assessment Review
Evolution Mini Assessment Review
__________ in 1859 wrote a book called “On the Origin of Species”, it was about __________ by __________ selection.
Charles Darwinevolutionnatural
__________ is a process in which organisms that are better able to survive and reproduce in an __________ are more likely to pass __________ traits on to future generations.
Natural selectionenvironmentfavorable (good traits)
Evolution Mini Assessment Review
An __________ is a characteristic or trait that helps an organism survive in its environment.
Adaptation
A species can become __________ if its environment changes to quickly.
extinct