In the previous activities you learned about evidence
In the previous activities, you learned about evidence to support theory of evolution. What is evolution? Evolution is the process through which species change over time. Turn to a partner and discuss some of the evidence that supports theory of evolution.
The basis for theory of evolution came from observations by Charles Darwin.
Darwin’s observations were made when he visited the Galapagos Islands, a chain of volcanic islands off the South American coast.
Darwin’s voyage provided insight on evolution.
Darwin observed differences among island species. 1. Variation is a difference in a physical trait. – Galápagos tortoises that live in areas with tall plants have long necks and legs. – Galápagos finches that live in areas with hard -shelled nuts have strong beaks.
Darwin’s Observations 2. An adaptation is a feature that allow an organism to better survive in its environment. – Species are able to adapt to their environment. – Adaptations can lead to genetic change in a population.
3. Darwin observed fossil and geologic evidence supporting an ancient Earth. • Darwin found fossils of extinct animals that resemble modern animals. • Darwin found fossil shells high up in the Andes mountains.
Darwin’s Observations • He saw land move from underwater to above sea level due to an earthquake. • Darwin extended his observations to the evolution of organisms.
Darwin’s Adventures, Observations, and Publications
One of Darwin’s most famous observations involved Finches, a type of bird. Watch the video clip of finches on the Galapagos Islands. Write down observations you make about the finches such as size, type of beak, what they eat, where they live, etc.
Darwin observed many similar looking birds with very different beaks. But how since they were all on one island?
Darwin’s observations made him wonder if the finches had evolved from similar species. Common Ancestor?
The Battle of the Beak Lab
Survival of the Finches Lab
After years of analyzing his observations, Darwin proposed that the birds were closely related finch species that were suited to different environments.
Darwin proposed that evolution could be explained through a process he called natural selection.
Natural Selection A process through which species that are best suited to their environment survive and reproduce at a higher rate than other members of the species.
Natural Selection
Natural Selection Simulation
Mechanisms of Natural Selection • • • Variations and Mutations Reproduction and Overpopulation Adaptations Competition Speciation Survival of the Fittest…Adapt of Die
One of the key ideas of natural selection is variation among species.
Within a species there are natural differences, or variations, in traits. Look at the images of the butterflies above. What causes these variations?
Many of the differences among individuals results from differences in the genetic material of organisms.
Which organisms can have a greater variation in genetic material? Why? Those who reproduce sexually have greater variation in genetic material because the organism receives genetic material from both parents.
Sometimes, a genetic variation is favored by natural selection (nature influences the variation) Successive Generations
Sometimes the genetic material itself within organisms changes, causing a new variation (mutation).
Sometimes the environment contributes to genetic variation such as the diagram to the right shows.
Variations and Natural Selection Activity
With a partner, discuss what is meant by the image below and explain why it does not happen this way.
An adaptation is any inherited trait that gives an organism an advantage in its particular environment. Turn to an elbow partner and identify a few examples of an adaptation in organisms.
Camouflage is a type of adaptation in which organisms appear to “blend” into their environment.
How does camouflage help an organism survive?
Where Am I?
Where Am I?
Where Am I?
Mimicry An adaptation where an animal or plant resembles another creature or inanimate object, either for defense or to gain other advantages. This is really a caterpillar
The King Snake resembles the Coral Snake so that predators will think it is poisonous.
Which one is using Mimicry? How do you know?
Did the King Snake and the Viceroy Butterfly decide to mimic the more dangerous animals? NO Turn to a seat partner and discuss how the King Snake and Viceroy Butterfly came to mimic the more dangerous animals.
Venom is another adaptation that has evolved over time.
Over time, venom in snakes has evolved through natural selection to be more effective.
Organisms do not “decide” or make a decision to evolve. The process of natural selection allows for organisms with more desirable traits to survive, reproduce, and pass the desired traits to their offspring over successive generations.
Speciation • Speciation is how a new kind of plant or animal species is created. • Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics. • The demands of a different environment or the characteristics of the members of the new group will differentiate the new species from their ancestors
Influence of Humans on Evolution: Moths of Manchester, England
The Peppered Moth
Peppered Moth Reading Activity
The Peppered Moth Simulation Lab
Gradualism and Punctuated Equilibrium Punctuated change takes place in spurts allowing us to see the change. The spurt can lead to long periods of no change and then another spurt will take place…EX. The Peppered Moths
Gradualism and Punctuated Equilibrium Very gradually, over a long time, the population changes. Change is slow, constant, and consistent. Ex. Human evolution
Review Time Darwin's theory consisted of two main points • diverse groups of animals evolve from one or a few common ancestors • the mechanism by which this evolution takes place is natural selection.
The Mechanisms • Organisms that adapt, mutate, reproduce with genetic variation, successfully compete with other organisms, and evolve into other species as needed will survive • Obstacles: new prey introduced, natural disasters, lack of food, overpopulation, reproductive issues, geographical isolation, and human influence
Breeding Bunnies Activity
Darwin’s Natural Selection Activity
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