Blog #14: Dissected Organisms Comparison

1. Grasshopper

     2. Frog

• Similarities

          -Both have at least one heart.

          -Both have a set of jumping legs.

• Differences

          -Grasshopper has an exoskeleton, frog has endoskeleton.

          -Grasshopper has wings, frog doesn't.

          -Grasshopper has a compound eye, frog has a normal eye.

Blog #13: What Was The Most Interesting About This Week's Dissections?

The most interesting things about this weeks dissections is definitely learning how the internal anatomy inside each animal is organized, and how each one works. I don't know why, but I really liked the crayfish dissection because of the way it looked and how we were able to take it apart.

Blog #12: What Surprised Me During the Worm Dissection?

There were quite a few things that surprised me when I did the worm dissection. The first thing that surprised me was the size of the worm alone. But the main thing that surprised me was the fact that the worm actually has individual working organs inside.

Blog #11: A Picture of Alteration of Generations and an Explanation

This picture has the same stages as the life cycle of a fern.

The Life cycle of a typical fern:

1. A sporophyte (diploid) phase produces haploid spores by meiosis.
2. A spore grows by mitosis into a gametophyte, which typically consists of a photosynthetic prothallus.
3. The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis.
4. A mobile, flagellate sperm fertilizes an egg that remains attached to the prothallus.
5. The fertilized egg is now a diploid zygote and grows by mitosis into a sporophyte (the typical "fern" plant).

Blog #10: Why is Dissection an Important Part of a Biology Curriculum?

Dissection is an important part of the Biology because it gives students a chance to see the inner workings of an animal for themselves.

Blog #9: The Different Forms of Community Interaction

• Competition- Competition occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time. An example of this is when two bears compete for a group of fish.

• Commensalism- Commensalism occurs when one member of the association benefits, while the other is neither helped or harmed. An example of this is when a clown fish uses a sea anenome as a home.

• Mutualism- Mutualism occurs when both species benefit from the relationship. An example of this is when a species of ants care for aphids, while the aphids produce a sweet liquid that the ants like to drink.

• Predation- Predation occurs when one organism captures and feeds on another. An example of this is when lions kill and eat a wild ox.

• Parasitism- Parasitism occurs when one organism lives on or inside another organism and harms it. An example of this is when wasps lay their eggs on organisms such as caterpillars.

 

Blog #8: What Have I Learned?

Throughout the third quarter, I have learned a lot. This is a list of things that I have learned about.

• DNA Mutation
• Amino Acids
• Fossils
• Evolution
• Half Lives
• Cladograms
• Ecosystems
• Organisms
• Habitats
• Population

Blog #7: Biome Comparison

Desert Biome:

• Hot in the day
• Very little precipitation. The little precipitation comes in rain.
• Tend to be near the equator.
• Plants and animals have evolved for life in the desert.

Tundra Biome:

• Very cold.
• Precipitation is in snow.
• Far from the equator.
• Ground is frozen under called permafrost.
• Plants and animals have evolved for life in the cold.

Blog #6: Which Level of a Food Pyramid is the Most Important?

I think that the plants/producers group is the most important group. It is the first group on the whole pyramid. Without it, the group above would suffer from a food shortage and die off. Therefore, causing a chain reaction all the way up to the top.

Blog #5: Are Humans Impacting the 6th Extinction Event?

Throughout Earth's history, there have been five major extinction events. Because of those events, many species either became endangered or extinct. But all of those events occurred due to a certain cause. There lately has been talk that humans may cause the next extinction event with pollution and such. I think it is completely possible that it could cause a major extinction event in the distant future with the effects of pollution. But that's not the only possibility, I think that another could also be caused by natural events such as major ocean level changes and asteroid impacts.

Blog #4: The Three Types of Selection

1. Stabilizing Selection

• Stabilizing selection is when the selective pressures select against the two extremes of a trait. Because of that a population experiences stabilizing selection. An example of this can be seen in plants. For example, one plant may be too short too thrive while another may be too tall. When combined, these too plants maintain a medium height. 

The effect of stabilizing selection on trait distribution.

     2.  Directional Selection

• Directional selection is when one extreme of the trait distribution experiences selection against it. Because of this, the population's trait distribution shifts toward the other extreme. Examples can be seen in giraffe necks. Shorter necks can't reach certain leaves, so in response, distribution of neck length shifts to those with longer necks.

The effect of directional selection on trait distribution.

     3.  Disruptive Selection

• Disruptive selection is when selection pressures act against those in the middle of the trait distribution. The result is a bimodal. An example can be seen in flowers. For example, one type of flower has variable heights and is pollinated by three different pollinators. One that prefers short plants, one that prefers medium plants, and one that prefers tall plants. If the medium sized height liking pollinator was to disappear from the area, the population would grow more short and tall plants.

The effect of disruptive selection on trait distribution.

Blog #3: What is Microevolution?

Microevolution is a change in gene frequency within a population. The four ways that that variation occurs are: selection, mutation, genetic drift, and gene flow. 

Blog #2: Why are Fossil Records Hard to Interpret?

Fossil records can be hard to interpret because of the fact that they could be deteriorated to the point where they are un-examinable.

Blog #1: Why is Evolution a Theory and not a Law?

In science a fact overwhelms a theory because a law is a widespread fact that has never ending evidence. A theory, on the other hand, is not exactly proven but is supported and believed my many scientists. Evolution is a theory because there is a bunch of evidence that supports it.

Blog #14: Semester in Review

The first semester of my sophomore year has been a busy one. Even though it has been more fun than freshman year, especially Tri-City Orchestra, it has been a lot more stressful due to my effort in trying to keep all my straight A's well..... straight.A's. Biology, for one, has had its ups and downs. My favorite activities of the semester are those that had to do with microscopes. I liked it best because I thought it was fun and very interesting. My least favorite activity of the semester is the Wiki project that we are doing right now. It is my least favorite because of the fact that it's really hard and confusing. If I could change one thing to improve the next semester, I would want to not have a project that is really confusing and uses a method that none of has have ever had experience with, like the Wiki project.

Blog #13: DNA and Crime investigation

DNA has changed how we investigate crimes in many ways. One way is that it helps clear people that have been wrongfully charged,  of their charges, and throws the correct suspect in jail. Even decades later. It is way more precise than older methods. But unfortunately there has been such a huge pile up of cases over the years, that there are not enough forensic analyzers.

Two examples of tests are:
1. Salivary Tests

2.  Blood Tests