DNA Structure Day

Today we took a quiz on the Journey of Man video, then we went over the structure of DNA.

Our white board looked like this by the end of class: 

As you can see, we drew the double helix  and labeled hydrogen bonds, nitrogen bonds, ATGC, and nucleotides.

Jump into the Gene Pool

Chapter 6 of Survival of the Sickest was about evolution that occurs inside our body, rather than the more popular view of outside evolution. 

It discussed how less than 3% of the DNA in our body is used to make proteins, and the rest (non coding DNA) comes from parasites that actually assist in shaping our evolution. 

Internal evolution is caused by slight mutations that, although most of the time are harmful, can sometimes result in beneficial adaptations for the body and then can be passed down through natural selection. Mutations are not random: they occur when the sequences of DNA change slightly, when the body is under stress. Jumping genes come in and delete or replicate genes to adapt to the stress, and this is when the sequences get changed and mutations occur. Our body changes its genes in hopes of beneficial mutations. Viruses, which make up some of the noncoding DNA, assist this mutations by grabbing onto areas in which the body believes are more likely for beneficial mutations. Once a beneficial mutation occurs, the body passes on the mutation through natural selection so that its offspring can have a higher survival and reproduction rate. 

Thus, through non-random mutations and the assistance of parasites, our body is able to evolve internally. 

Journey of Man Day 2

Today, we finished journey of man.

Just because the main guy totally looked like Luke Walton.

Homework:

1. The significance of Gregor Mendel is that he swept away the confusion of blending inheritance by breeding pea plants and seeing that both forms of a trait could reappear undiluted in future generations

And the alternative forms of the trait, though not appearing, were still not blended away in the offspring. Mendel gave us what we know about dominant and recessive genes.

2. Francis Crick and James D. Watson created the structure for DNA.

It looks like this:

3. The five different types of DNA mutation are substitution of one letter for another, deletion of a letter, duplication of a letter, insertion of a letter, and inversion or translocation of a letter (letter is in different order). An example of substitution would be instead of the sequence ATAGCA it would instead be CTAGCA. An example of deletion would be instead of ATAGCA it would be ATAGC. An example of duplication would be instead of ATAGCA, it would instead be ATAGGCA. an example of insertion would be instead of ATAGCA, it would be ATAGCAG. An example of inversion or translocation would be instead of ATAGCA, it would be ATACGA. 

4. Evo-devo is a subspecialty within evolutionary biology that concentrates on studying the effects of changes in important developmental genes and their roles in evolution.

5. A connection between human migration and lactose tolerance is that East Africa contains a strong percentage of people who are lactose tolerant, while in the rest of the world it is a minority. This means that early humans in East Africa were lactose tolerant because they were a milk-dominated society, but as they migrated to different parts of the world less became lactose tolerant because the trait was unneeded in less milk based societies.

Journey of Man Day

Today, we reviewed our test and what we learned from the homework assignment the night before, then we watched a video regarding the "Journey of Man," and how we got to where we are today.

Response to Article 1, "Does Race Exist?"

Nowadays, it is often preached that race should be ignored because we are all humans at heart, that just because our skin color is different doesn't mean we don't function the same way. Recent findings have supported this theory and have given it meaning in the biological world. 

Upon reading "Does Race Exist," I have learned that the concept of race is invalid in comparing humans and our ancestors. When we think of race, we think of physical appearance such as dark skin, or light skin, curly hair, or straight hair, brown eyes, or blue eyes. Although race does sometimes account for different resistants to disease, these physical differences are essentially meaningless in providing evidence for where we came from. People are affected by numerous variations and mutations and although two people may have similar appearances, they could come from completely different environments and have completely different ancestors. Because people look similar does not mean that they are genetically similar. Also, in contrast, people may seem genetically dissimilar because natural selection has exaggerated the differences in appearance, making them more similar underneath than on the surface. Thus, scientists must look at genetic makeup to determine where we came from.

As explained in "Journey of Man," evolution is created through variations of genes that  are then passed down from generation to generation and then those genes are then variated some more down the line. Some variations do not occur within genes, and do not directly affect a particular trait. These variations, known as polymorphisms, are variations in the building blocks of DNA, which scientists study to show individual variations in traits and genetic diseases. Upon studying polymorphisms, scientists are able to see the these variations come from natural selection. As variations that allow species to survive and reproduce better are passed on, the DNA strands of the next generations differ from their ancestors and thus make the search for our ancestors more difficult.

Another tool of polymorphisms that scientists use are Alus, or similar pieces of DNA. Once an Alu is placed, it remains there for eons and is passed onto the following generations, giving scientists another tool to track down our ancestors. For example, if two people have the same Alu then they are descendants of a common ancestor. Scientists have been able to break the myth of race using Alus. By comparing Alus from different populations and sorting people off of their Alu similarity, there was little parallel between Alu similarity and race. When scientists studied different populations based on their Alu differences, they were able to draw connections from all the populations to two places, thus proving that genetic differences can be studied to discover geographical origin, or at least obtain a small sense of it.

Genetic variations account for different defenses against diseases. For example, people that lack the CCR5 polymorphism are less susceptible to HIV-1 because it hooks onto the CCR5 in order to enter our system. We have been able to see that polymorphisms affect different populations differently. For example, a common polymorphism found in Europeans delays a certain type of disease while the same polymorphism accelerates the disease in Africans. Therefore, but studying different details of genetic differences, scientists have been able to separate different populations into different classifications and are that much closer to discovering our human origin. 

Test Day

The test was fairly straightforward, and it was graded very quickly along with our Paleo projects.

Yeah...

Allele Frequency Lab Day

Today, we learned how to find allele frequencies and do Hardy-Weinberg Problems, like the one below:

Hardy-Weinberg problems are all about the equation, p^2 + 2pq + q^2. In this equation, p^2 is the homozygous dominant gene, meaning the same dominant gene twice, 2pq is the heterozygous gene, meaning one dominant one recessive gene, and q^2 is the homozygous recessive gene, meaning 2 recessive genes. Homozygous dominant and heterozygous genes will always show the dominant trait. The only way the recessive gene can appear is through the homozygous recessive gene. This is why the recessive gene always stayed alive in the tiger lab, but couldn't appear often enough to drastically affect the tiger population. 

The Bengal tiger lab: 

We then took home a cladogram and evolution quiz:

Parents Day

Today, we first gave parents a taste of the labs we do in class by collecting data for 48 hours for the brine shrimp lab. 

Brine shrimp after they hatch.

Next, we did an experiment with masculine and feminine faces. Morphed faces were shown on the board and it was our job to put which we thought was more attractive.

We found that masculine faces were chosen because a strong, work-horse mate was desired and feminine faces were chosen because a caring, nurturing mate was desired.

I got half and half for my male category and mostly feminine for my female category, meaning that I like a mix for male and I want a very nurturing and good parent female for a mate.

Left feminine right masculine.

Shrimp Egg Lab

In class today, we started by sorting snail shells and discussing various differences we saw between the shells, such as shape, size, or design. We concurred that these differences happen due to mutations and different species. Lastly, we hypothesized why some shells had 2 shells and it turns out the second hole is from predators sticking their tongue in and eating the snail. 

We then moved onto a natural selection lab.

Shrimp Egg Lab

First, we filled 5 beakers with different percentages of NaCl dissolved into each. Next, we placed double sided tape on 5 microscopic viewing slates. 

Then, we placed mini shrimp eggs on each (around 20) and placed the slates into each beaker. 

Lastly, we placed the solutions from each beaker into a separate container, and close the lid shut. We now have to wait 24 hours to test the results...

Paleo Project Announcement Day

Today, we reviewed evolution in relation to plants and disease, particularly in fava beans.

Then, we took a short quiz.

The majority of the class was spent picking and working on our Paleo Project.

PROJECT

James and I chose to research early kangaroos.

We have learned that early kangaroos were more like dogs, with 4 legs, claws, and sharp teeth. Here is a picture of a Nambaroo gillespieae:

We also discovered that these kangaroos evolved from possum-like tree-dwelling marsupials in Australia, similar to the one in these pictures:

This is what our research has consisted of so far.

We are continuing to discover new clues regarding kangaroo evolution every day.