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EvolutionEvolution
GIANT MISCONCEPTIONMAN DOES NOT COME FROM APES.WE SHARE A COMMON ANCESTOR.
What is the theory of EVOLUTION?
• Scientific explanation vs. Religious explanation
• Different theories of evolution exist. In this class we will only focus on the scientific theory. You are a free thinking individual and have the right to believe in the theory of your choice!
Evolution
• Evolution is a change over a period of time.
• Evolution is the process by which modern organisms have descended from ancient organisms.
Lamarck’s Theory of Evolution• In 1809, Lamarck
proposed that by choosing to use, or not use, an organ, different organisms acquired or lost certain traits over time. These traits could be passed on to offspring; and in this process a species changed over time.
A closer look at Lamarck
• Principle of Use and Disuse – organisms can control and change their size and shape by using their bodies in different ways.
By trying to use their front limbs for flying Birds eventually changed limbs into wings.
A closer look at Lamarck continued…
• Principle of Acquired Traits – the concept that acquired characteristics could be inherited.
During its lifetimean animal somehow can change its body structure
According to Lamarck if you spend your life lifting weights your children
will have giant muscles too!
Yeah! Pump it UP
Charles Darwin – the man, the myth, the legend!
• Born in England in 1809 Darwin set sail on an adventure that would change the world of science!
• He is considered the “father of evolution”
H.M.S. Beagle
Some of Darwin’s Questions
• Why are there no rabbits in Australia when the environment is perfect for rabbits?
• Why are there no kangaroos in England?
• Why do fossils sometimes resemble species that are still alive?
GlyptodonFossil
Armadillo
Saddle back tortoise – Hood Island, Galapagos
Dome Shelled Tortoise – Isabela Island, Galapagos
Beaks of Finches
• Darwin noticed 14 different beak shapes in the finches he saw on the Galapagos
• The beaks seemed well adapted to the available food sources on the different islands.
Flightless cormorant
• Only found on two of the Galapagos islands.
• Only 800 pairs left
• Lost ability to fly
Blue Footed Booby Video
• http://media.pbs.org/ramgen/odyssey/20000713_video.rm?altplay=20000713_video.rm
Putting Darwin’s Ideas Together
• Darwin did not complete his conclusions about evolution until 29 years after he began his journey to the Galapagos
• He summarized his findings in his revolutionary book, THE ORIGIN OF SPECIES in 1859
Darwin’s Theory of Evolution
• Natural Variation - there are differences among individuals within all species
Darwin’s Theory of Evolution
• Evolution by Natural Selection–Struggle for existence
–Survival of the fittest
The Struggle for Existence
• Members of each species regularly compete for food, living space, and other necessary resources.
Stronger male lions are more likely to get food, protect their range, and have a pride of females ready and
willing to mate!
Survival of the Fittest
• Fitness – the ability of an individual to survive and reproduce in its specific environment
• Adaptation – fitness is a result of adaptation, or inherited characteristics that increase an organism’s chance of survival and increases the chance of reproducing
What happens when a species is does not have an adaptation
that is necessary to its environment?
EXTINCTION
• After the industrial revolution in Europe, soot covered many of the trees in industrial areas. Which moth do you think is most fit for the soot covered tree environment?
Peppered vs. Non-peppered
Moths
Green vs. Brown Grasshoppers
Types of adaptations
• Camouflage – ability to blend in with one’s surroundings
Countershading
Hazard colors warn predators that they are toxic!
Poisonous Coral Snake
Poisonous Berries
How do we get these adaptations?
• Adaptations occur when there is a genetic mutation in an organism’s DNA
• Sometimes the mutation is favorable, or helpful.
Darwin’s Evolution
• Common Descent – all living things share common ancestry
• Man does NOT come from apes, but man and apes share a common ancestor
Evidence of Evolution
• Fossil Record• Geographic Distribution• Homologous Structures• Vestigial Structures• Analogous Structures• Embryology• DNA evidence
The Fossil Record
• Fossils that formed in rock over the course of time are evidence that species have been gradually changing for millions of years.
Geographic Distribution
• How could finches on different islands be so different than finches from the mainland?
Homologous Structures
• Homologous Structures – different body parts from various species have different functions yet are composed of the same bones and all stem from the same embryonic cells
Homologous Structures
Vestigial Structures
• Vestigial structures / organs – a structure or organ that has no function
• May be evidence that the structure was useful to a common ancestor
Vestigial Structure in Whales
Structures that were thought to be vestigial. We now know the function of
some structures.
Analogous Structures
• Structures that share the same function but is NOT derived from a common ancestor
Embryonic Evidence
• In the early embryonic stages of development many vertebrates (animals with backbones) are so similar they are difficult to tell apart.
DNA Evidence of Evolution• Humans and Bonobos share 98.4% of the
same DNA
Cladograms-diagrams that show evolutionary relationships
SIMPLE TO COMPLEX
• In general, simple organisms evolve into more complex organisms.
Punctuated Equilibrium/Evolution
• States that evolution of species occurs very abruptly. Cladograms have abrupt right angles on branches.
Gradualism
• Cladograms show that evolution of species occurs over the course of a long period of time
Currently gradualism is the accepted theory of evolution
