EvolutionBlog

Hello(:

I'm fully aware than learning about Evolution isn't exactly your idea of fun. As a result I havecreated this webquest to in order to make the process of learning a little bit more fun.

Hope you enjoy!

Evidence Of Evolution:

Fossil Record:

As layers and layers of sediments get deposited on top of each other, the oldest layers are on bottom and the youngest layers are on top.

The sediment can include once living organisms. The reason this can be used as evidence of evolution is because fossils in the bottom layers differ from the organisms alive today.

Homologous Structure:

Homologous Structure- simply means that there is a relationship between a pair of structures, due to having come from a common ancestor. 

Evolutionary theory explains the existence of homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. So basically species started out the similar but because of natural selection these similar species have changed over time.

DNA Analysis:

During the process of DNA analysis it was discovered that our DNA sequences are about 99.9% identical. We all have pretty much the same set of genes. The same result was found when the with the DNA of animals.

All mammals have the same genes, but those genes will differ in exact base sequence from each other. The belief is that if all mammals are very closely related that means we come from the same ancestor.

Similar Embryological Development:

Discoveries over the years have shown that many different animals appear simlilar in the embryo stage, so close in fact it's difficult to tell them apart. For example, fish embryos and human embryos both have gill slits. Later on though fish develop those slits into gills, but for humans they disappear before birth.

Similar Embryological Development simply means that because different species develop similarly, we must be related, implying we come from a common ancestor.

Geographic Distribution of Organisms:

Distribution of Organisms explains that animals in different areas come from a common ancestor even though they appear altered. The reason they appear altered is because different conditions call for different characteristics.

"Evolutionary theory predicts that islands that have similar environments, but are in different parts of the world, will not be populated with the same species. Instead, these islands should be populated with plant and animal species that are closely related to the species on the nearest mainland, even if the environment there is very different from the island. This is what is seen throughout the world."