Biology Blog
Biology 1 - Middlebury Union High School - Spring Semester 2018
May 14 - Kiwi Beaks and Micro-evolution
How are organisms selected for by nature? How does evolution pick the traits that will be passed on to the next generation? Today we ran a simulation that tried to answer these questions, using a surprisingly cute animal: the Kiwi bird!
Like most small birds, Kiwis use their beaks to eat seeds stored in plants. In our simulation, we used straws of different shapes and sizes to simulate beak variation in the gene pool. We then used our straws to scoop up seeds to determine the most efficient beak traits. Those who collected the least seeds after time was up died and were reborn in the most successful group.
Over the course of a few generations, the most successful beak shape had the highest population, demonstrating how a population changes in favor of successful traits.
May 9 - Evolutionary History and Fossils
For researchers studying evolutionary history, the only way to determine relationships between long extinct creatures is to examine fossils. Using the morphological characteristics of the fossils and the age of the rocks they're found in, archaeologists can accurately show how one species evolved into current species.
One example of how fossils have helped tease apart evolutionary links involves dinosaurs. By analyzing bone structures and rock formations, researchers have been able to confidentially determine that modern birds are the decedents of ancient dinosaurs.
We discussed the concept of ancestry, and what makes an ancestor. In our fossil diagrams, an ancestor was defined as the junction where speciation has occurred. Each ancestor is discovered by examining the fossil record and determining how the species found there relate to each other.
May 2 - New Unit: Biodiversity and Evolution
We began a new unit today! We're really cruising along. We've begun to move away from the small things like cells and DNA and are now focusing on the big things like organisms and populations. We started by defining the term "species". We quickly realized that even biologists out in the field don't have a specific definition for species.
Next, we examined a dichotomous key of salamanders and tried to identify the different species based on the clues we were given. We then did the process in reverse, making our own dichotomous key based on our observations of our five mammals.
Finally, we picked our own group of organisms and made dichotomous diagrams and keys for them. We had bones, fish, and insects to choose from, leading to a wide variety of different classifications.
April 30 - Heredity Assessment
We began wrapping up our genetics unit with a quick heredity assessment. We aimed to demonstrate our understanding of different kinds of inheritance by providing definitions of words like "co-dominance" and giving real life examples, like blood type.
April 20 - Blood Typing Videos
Today we made video tutorials on how to type our blood! Our videos demonstrated the steps involved in determining blood type that doctors and researchers around the world follow.
In order to make our videos, we critiqued videos made by other biologists and determined what made them successful or not. We found that text speed, conciseness, and camera stability were all important things when creating the tutorials.
Take a look at the videos we made! Compare them with the videos made by other biologists. How did we do?
Our Playlist!
April 18 - Dragon Inheritance and Blood Types
We wrapped up our dragon inheritance activity, creating a wide variety of genetic variation in our population! We also learned new inheritance words: codominance and incomplete dominance.
Codominance is when both alleles are simultaneously expressed in the heterozygote, while incomplete dominance is where one allele for a specific trait is not completely expressed over its paired allele, creating a blended trait. We applied these concepts to our dragons, creating unique coloration in the offspring.
Codominance is also at work in human blood types. The "A" and "B" alleles aren't dominant over each other, so they each get expressed in people with the AB blood type. We discussed how important understanding blood types is to our health.
Need review on Punnet Squares? Blood types? Check out the resources below!
April 12 - Starting our Genetics Unit!
Today we began our unit on genetics! This unit will introduce us to concepts like the gene and how we inherit genes from our parents, along with the idea of dominant and recessive genes.
Our goal today was to discuss how humans have 46 chromosomes and 100,000 genes inherited from our parents. These give us the traits we observe in the people around us.
We began with a simple activity: was it possible to determine who Mr. Johnstone's biological father and sister are, just by looking at their faces? As it turned out, the majority of us could spot the true relatives, even when Barrack Obama (a dead ringer for Mr J.) was thrown into the mix. This activity served to show us that siblings are more genetically identical to each other than to their parents and that humans are extremely adept at picking out facial similarities.
Next, we detected genetic variation among our classmates with different papers, dipped in either sodium Benzoate, thiourea, or PTC. Some students were able to detect all three chemicals, some only one or two, while others couldn't taste any of the chemicals. We graphed our results and found evidence of three distinct genes responsible for being able to taste each chemical.
Finally, we looked at Mr. J's son, Porter, and his unique genetic disorder. Porter has a rare disease called OTCD, where he lacks the proper gene that codes for the OTC enzyme. This enzyme is a vital part of the urine cycle, converting ammonia into less dangerous citrulline. Ammonia is a deadly neurotoxin, meaning Porter was at risk of death from the moment of his birth.
April 10 - Portfolio Work
We continued to work on our portfolios today, creating Google sites to demonstrate our understanding of the past quarter. We used images, notes, and lab reports to prove our competency in Biochemistry, Cytology, and Genetics.
Make sure to review notes, labs, assessments, and our Biology Blog!
April 4 - Cellular Respiration, Fermentation and Yeast
Fermentation is a special type of cellular respiration. We conducted an experiment to test the affect of different amounts of food on the amount of cellular respiration in our yeast cells.
Hypothesis: Giving more food (sugar) to the yeast will results in more carbon dioxide produced by the yeast.
We found it difficult to experiment with the yeast and our data was inconclusive as some groups concluded that more food does correlate with more carbon dioxide and other groups made the opposite conclusion.
April 2 - Why do living things need oxygen?
We started our quest today to understand the importance of oxygen to biological systems. We all know that "living things need oxygen". But, why?
We began our inquiry with a couple interesting videos that helped us understand how the body cells utilize oxygen and what happens when oxygen is not present.
So, we learned that oxygen is used in a very specific set of chemical reactions that help convert food into energy that is used by the cell. This is called CELLULAR RESPIRATION.
March 27 - Is photosynthesis magic!?
Of course not! But, it seems magical. Plant cells using sunlight to create their own food! We have been using the results of our photosynthesis experiment to help us understand the elements of this incredible cellular process. We discovered that the photosynthetic cells need water, carbon dioxide and light. We also proved that they produce oxygen. And, finally our data showed that a number of variables impact the chemical process of photosynthesis.
Teams experimented with variables such as light color, carbon dioxide concentration, acidity, temperature and leaf surface area.
March 19 - New Unit: Advanced Cytology
We are cruising along! We start our new unit today, Advanced Cytology. In this unit we will learn about three main topics:
- Cell Division
- Cellular Respiration
- Photosynthesis.
These are all complicated processes that are critical to understanding how cells stay alive and how organisms function.
Our first topic, cell division is partly review for many students. So, we focus on advanced inquiry into this topic which includes seeking answers to questions such as
- How long does cell division take?
- How is cell division related to cancer?
Today, we gathered data of real cells with the help of our microscopes. We calculated relative time that it takes for each stage of mitosis to occur. Interphase takes the longest, and Anaphase is the shortest!
March 12 - Wrapping up Unit 2
This week biology students are working to complete our final Unit 4 Assessment. This is a comprehensive assessment of the concepts we learned in this unit including cell structure and function, the biological hierarchy, and cells and disease.
Students will create an educational pamphlet or brochure that helps patients and their families learn about specific diseases.
March 5 - More on Cells and Disease
Here is our statement of inquiry for this unit:
Developing and using models that show the relationship between cell structure and function helps us understand diseases and disorders and develop effective treatments.
In the first part of the unit, and in our first writing assignment on cells, we focused on how disease is caused by malfunctioning cells. This is often a permanent disease, and often has a genetic origin. People are treated for the symptoms of these diseases, but it never goes away. So, for this next part of our unit, we are learning about how "temporary diseases" caused by bacterial or viral infections can affect the cells of the body and how these diseases are treated and how a person overcomes the infection with the help of the complicated human immune system.
In this part of the unit, we will focus on the immune system, but more specifically on the function of the cell membrane. Here are our first two learning objectives:
- Students will learn what the cell membrane is made of and what functions it performs.
- Students will learn how materials are transported through the cell membrane.
We are using a student-paced blended learning model for this learning. We use "hyperdocs" with links to learning resources and activities, and assessment and reflection opportunities. Students are learning how to learn on their own, and EVALUATE THEMSELVES!
Here's an example of our hyperdoc learning (scroll to see the whole document).
February 27 - Microscopes
Welcome back from our Mid Winter Break! We are continuing our quest to understand cells by learning how to effectively use our compound light microscopes. Keeping with our theme for the unit: cells and disease, we are focusing on microscope skill that a medical professional might use when viewing real cells to help diagnose disease. First we practiced our illustration skills, then we used our analytical skills to estimate the size or objects and cells in our field of view. Some cells are big and some are small. How do you measure something microscopically!?
We used some real plant pollen samples to get experience viewing objects of different sizes and measuring them.
We estimated the sunflower pollen at 25 micrometers and the lily pollen at a whopping 80 micrometers! Pollen grains are made of 1-3 cells, all of which are involved in fertilizing the plant egg cell. Each plant species has a unique pollen shape and structure. They are beautiful under the microscope!
February 15 - New Unit!
This week we started our new unit! Cytology, the study of cells. Now this isn't your average study of cells. We are focusing on being critical thinkers during this unit, so instead of re-learning and focusing on cell structure and organelles, we will focus on some of cell structure as it is related to human diseases and disorders. Understanding human disorders at the cellular level is exactly what real doctors and researchers are doing to help people afflicted by symptoms of these conditions.
We developed a model of the human heart organ to help us understand the cell hierarchy and why body parts must be built from numerous different types of cells and tissues. The heart just wouldn't do what it does if it didn't have cells that did specific functions.
Also, we watched a video about a human disorder called Progeria. This disorder is a result of malfunctioning cell nucleus. These damaged nuclei cause cell DNA to be damaged quickly, and cause people with this disorder to age very quickly. Here is more info on Progeria.
February 8 - Lipids and Carbohydrates
Today we started with an exercise to identify relationships between the biomolecules we've been studying. Students were told to pick two of the biomolecules (proteins, carbohydrates, lipids, or nucleic acids) and write a simple sentence that described a relationship between the two substances.
Here are a few of the responses:
- Lipids and carbohydrates are related because they both have an energy function, one storing energy (lipids) and the other providing a source of energy (carbohydrates).
- Proteins and nucleic acids are related because the information stored in the DNA includes the code to make the proteins a cell needs.
- Nucleic acids and carbohydrates are related because sugars are carbohydrates and part of the DNA molecule includes Deoxyribose, which is a type of sugar.
- Proteins and carbohydrates are related because proteins such as Insulin help regulate how a cell obtains and uses its sugars (carbohydrate).
These are great responses and show that the students have a strong skill in identifying relationships.
Then, we spend our remaining time testing various biological substances for the presence of Glucose (a simple carbohydrate). Here are some photos and our results.
February 6 - More Biochemistry: Carbohydrates
So far we've been learning about Nucleic Acids such as DNA and also learning about proteins. Today we began learning about two other important "Biomolecules": carbohydrates and lipids. We built molecular models out of our plastic chemistry kits and examined the differences between simple sugars such as Glucose and larger molecules such as Starch. We learned that sugar gives you "energy now" because it is digested and processed by cells quickly, but Starch gives you "energy later" because it takes time to break down the larger complex starch molecule into its sugar building blocks for the cells to use.
February 2 - Study of DNA
We continue our quest to understand cell biochemistry by studying DNA! We watched an intriguing video about mosquitoes that are being genetically modified to help stop the spread of insect borne diseases in South America. Then, we used the DNA Learning Sequence "hyperdoc" to help us learn about the specifics of DNA and help us understand the answer to two main questions which are:
- How do the researchers really change the DNA of the mosquitoes?
- How why does changing the DNA change the actual organism?
We also extracted our own DNA!
January 31 - Enzymes Assessment
Today we wrapped up our study of enzymes with a small assessment (see below).
January 28 - Enzyme Lab Analysis
We continued to learn more about enzymes today. We analyzed our experimental results from our lab which demonstrated the function of the "Peroxidase" enzyme in both the potato cells and the yeast cells (see data below). Students showed that they know how to create valid conclusions and use biological knowledge to propose reasoning for our results.
January 26 - Potato Biochemistry
We are investigating the chemicals inside potato cells. Specifically, we are exposing potato cells to hydrogen peroxide and observing the chemical reaction between the peroxide and an enzyme inside the potato cells called "Peroxidase". This enzyme breaks down hydrogen peroxide into water and oxygen gas. The oxygen bubbles are fascinating to watch!
This is our first unit, Biochemistry. Enzymes are proteins and proteins are just one kind of chemical that can be found inside cells. Proteins are important to biology and so are other "biochemicals" that we will study later.
We watched some instructional videos to help us learn about how enzymes work.
January 24, 2018 - Welcome!
Today is day two of biology class. Welcome! I will post to the Biology Blog about twice a week to keep everyone updated. If you are a student out absent or a parent who wishes to keep updated on our class, I hope this blog will be helpful. A link to our syllabus can be found above. ~ Mr. Johnstone (cjohnstone@acsdvt.org)
