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Natural Selection - A gradual cause of evolution where helpful traits are passed onto to future generations while bad traits are less likely to be passed down.

Natural Selection Student Theories

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How might your assigned trait have evolved over time?

You are going to theorize how your trait evolved. Here is the list that will be assigned throughout groups in the classroom. Each can be thought of as a separate phenomenon, but all will be viewed through the lens of Natural Selection.

Stripes on a tiger
No legs on snakes
Hard shells on bird eggs
Needles on a cactus
Long ears on a rabbit
Horn on a rhinoceros

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You are going to use the example of how giraffes evolved longer necks to model your own theory of how your trait evolved.

DO NOT internet search the answer to your trait. The giraffe example below will be used as the model for your theory. The quality of your work will be judged on your creativity, not what scientists have agreed upon.

This is your own copy of this presentation, so use and transform it into your own. Your slides are at the end of this document

This slide presentation is based upon the information found in this presentation.

The slides associated with Natural Selection are the ones that will be graded and each can earn up to 5 points so the assignment is worth 20 points.

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What is believed to be true about evolution:

Organisms have changed over time, and the ones living today are different from those that lived in the past. Furthermore, many organisms that once lived are now extinct. The world is not constant, but changing. The fossil record provided ample evidence for this view.

All organisms are derived from common ancestors by a process of branching. Over time, populations split into different species, which are related because they are descended from a common ancestor.

Change is gradual and slow, taking place over a long time (thousands to millions of years).

The mechanism of evolutionary change was called Natural Selection.

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The following BLUE slides are an example

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Theory of how giraffes got their long necks.

Organisms tend have have more offspring than can survive. Offspring often starve, are hunted, get sick, or are out competed by other giraffes. For the species to survive, two or more offspring from parents need to survive to reproduce someday. This has to continue for MANY generations.

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Theory of how giraffes got their long necks.

2. Organisms within a population differ from each other and those best suited will live to reproduce. There is variation throughout a population. In giraffes, some will have shorter necks, some will have average length necks, and some will have longer necks. These variations will happen in every population for MANY generations

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Theory of how giraffes got their long necks.

3. Offspring tend to be like their parents, including their adaptations , and the best adapted are more likely to reproduce….so giraffes with longer necks will most likely have offspring with longer necks. Longer necks appears to be an advantage over shorter necks and this trait will again be likely to be passed onto the offspring. These traits will be passed on for MANY generations to cause giraffes to be adapted to changing environments.

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Theory of how giraffes got their long necks.

4. There must be a struggle to survive and reproduce…”SURVIVAL OF THE FITTEST”. The shorter giraffes have a harder time surviving due to competing for food with the taller giraffes. They may find shorter plants to eat from but then they will be competing with other animals for food. The best suited to survive will most likely have offspring and pass on the traits that enable them to survive. When this is repeated for very long periods of time over MANY generations, species can look dramatically different from how the looked a long time ago.

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Start your presentation here

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Make your title slide here

Include names of people in your group and the name of your trait/ organism