Evolution In a population

How do populations evolve over time?

As Individuals are selected by natural selection genetic makeup of the population changes over time. Each generation has increased fitness as favorable traits become more common. Natural selection is not the only thing that can change a population. There are 5 sources of evolution. Mutation, Gene flow, Non random mating, Genetic drift, and Natural selection

What is the Hardy-Weinberg equilibrium?

The Hardy-Weinberg equilibrium describes a non evolving population that preserves allele frequencies. Why do we use the Hardy-Weinberg equilibrium if it doesn’t occur in nature? It allows us to have a baseline to compare populations with. We can use it to test genotype frequency and we can test to see how that population compares with the Hardy-Weinberg equilibrium.

Descent with Modification

Learned about the story leading up to Darwin’s theory of evolution. How is it that for so long so many people assumed everything was just created how it was at that time currently. How long did it take Darwin to fully come up with his theory? Are the methods of classification that scientists used back then still used today?

In terms of understanding evolution. This story helps to create a clearer picture of how evolution actually occurs overtime and how our understanding of it has changed overtime.

Natural Selection

My Biggest take away from this week was that in many circumstances species in isolated environments often evolved from one common species, for example the finches we learned about. One species evolved into 13 due to natural selection because of very diversified environments and food sources. I wish I knew more about how these changes actually came about. What specifically causes such extreme deviations in terms of physical attributes and traits. But that relates more to DNA coding and genes as a whole. I know that these different traits are caused by mutations, but what specifically causes those mutations. How is it that the genes of one animal can be so different than that of the generation before.  Another important aspect that I learned about natural selection and evolution as a whole is that it doesn’t have to take millions of years for a species to evolve. As demonstrated by the finches, they were able to be selected in a single generation after a single endangering event. The species became a more predominately large beaked group after the smaller beaked birds had a food shortage and then became a smaller beaked group after their food became more abundant and the larger beaked birds less abundant.

Tendrils are specialized stems that have a threadlike shape. Tendrils are used by climbing plants for support. They are found on Grapevines, squash, sweet pea plants and various other vines.

A woody plant produces wood for its structure. Woody stems have more strength and are typically found on trees, shrubs, and lianas.

A herbaceous stem is a stem that has no woody stem above ground. These plants do not live year round they tend to be annuals, perennials, and biennials.

Seed dispersal is when seeds are moved or transported away from the parent plant. This helps the species spread and thrive. Because plants themselves cannot move the rely on outside factors to help them spread.

Radial symmetry is symmetry around a central axis. If the organism were split in half it would become two identical halves. Seen here with this flowers pedals.

Pollen is a yellow powdery substance that is released by the male plant reproductive organ. The pollen fertilizes the female ovule. Pollen is typically transported by insects, wind , or other animals.

Female pine cones act as a trees female reproductive organ. Female pinecones are lower on the trees than male ones so that when pollen is released it reaches the female pinecone more easily. Female pinecones have loose scales to help catch the pollen.