INTRO TO CELL REPRODUCTION
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Biodiversity and Reproduction
Let's get started watching a video that took me way too long to make, to consider some things about biodiversity and how it relates to cell reproduction!
Everything we see in the market comes from a long chain of events, starting with one single cell to the full organism we're used to seeing. This process is what makes life continue. Everything alive that we see depends on this chain of events. This is why is it so important to understand how these processes work.
Think about your favourite fruit, or the fish in the market. Can you trace how it was made, from cell division to where it is now? What do you think it takes for these living things to grow to what you saw in the video?
Think about your favourite fruit, or the fish in the market. Can you trace how it was made, from cell division to where it is now? What do you think it takes for these living things to grow to what you saw in the video?
By now, you have an idea of some of the parts needed for things to divide and grow. Last week, we engaged in a cell play to help us understand the cell division process. We will be looking into each phase very closely; I hope you like this topic as much as I do!
Did you know?
In the very beginning of time, when cells started appearing, they did not divide automatically; rather, they grew and grew so big, that food from one side of the cell could not reach the other side of the cell. The cell also had a hard time moving around, particularly before movement was a thing. This precipitated a split mechanism, which made the cells divide into two, thus making it easier for both of them to survive! Scientists were able to replicate this phenomenon in a laboratory by using protocells. This focus on survival continues to dictate how everything in the world reproduces, from the tiniest virus to the biggest whale.
We mentioned bees in the video. They are super important! Without bees, such as those that pollinate this apple blossom, there would be no apples — or beets, lettuce, sunflowers, and a host of other plants that provide the world’s food. Bees help transfer pollen, initiating a series of cellular events that enable most flowering plants to reproduce and thus ensure the survival of their species.
“Given the estimates that over ¾ of flowering plant species rely or benefit from pollination services, these oft-neglected insects are critical components to maintaining ecosystem and agricultural sustainability.”
— Sheila Colla, PhD, North American Co-Coordinator of the IUCN Species Survival Commission, Bumblebee Specialist Group
“Given the estimates that over ¾ of flowering plant species rely or benefit from pollination services, these oft-neglected insects are critical components to maintaining ecosystem and agricultural sustainability.”
— Sheila Colla, PhD, North American Co-Coordinator of the IUCN Species Survival Commission, Bumblebee Specialist Group
Something to think about...
- What do bees get from the flowers they visit? What do the plants get from the bees?
- Bees are not the only pollinating animals. What other animals help plants reproduce?
- What questions do you have so far?
Why do Plants Make Fruit?
Fruit is one of the most expensive things a plant can produce. It takes energy, sugar, water, and time to grow a juicy apple or a cluster of berries. So… why bother? The answer lies in the plant’s clever strategy for reproduction. Inside every fruit is one or more seeds — the plant’s future offspring.
But seeds need to get away from their parent to survive. If they fall right beneath the tree or bush, they’ll compete for sunlight, water, and space. So plants evolved a trick: wrap the seed in something irresistible. Animals eat the fruit, enjoy the tasty reward, and unknowingly carry the seed inside their bodies. Later, after the animal has wandered far from the parent plant, the seed is released — yes, through poop — often in a little pile of natural fertilizer. Genius!!
But seeds need to get away from their parent to survive. If they fall right beneath the tree or bush, they’ll compete for sunlight, water, and space. So plants evolved a trick: wrap the seed in something irresistible. Animals eat the fruit, enjoy the tasty reward, and unknowingly carry the seed inside their bodies. Later, after the animal has wandered far from the parent plant, the seed is released — yes, through poop — often in a little pile of natural fertilizer. Genius!!
The Nature Walk
Cell theory states that all living things are made up of cells, which are derived from previously existing cells. But how much life can be found in a city? In a neighborhood? Or even -- in a single block?
Let's find out what kind of biodiversity we have around NWSS by doing a nature walk. In this walk, we will use the app Seek, by iNaturalist. It's like Pokemon Go, but with plants and animals! Every time you see a new animal or plant, stop and take a picture.
Let's find out what kind of biodiversity we have around NWSS by doing a nature walk. In this walk, we will use the app Seek, by iNaturalist. It's like Pokemon Go, but with plants and animals! Every time you see a new animal or plant, stop and take a picture.
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SOME TIPS:
- LOOK CLOSELY! Sometimes tiny things are under leaves. Sometimes a tiny plant is almost invisible!
- Lift rocks and branches (be gentle!) Tiny animals like the moisture under rocks. Place the branch or rock gently ack again once you take your picture.
- The branches and the leaves of a plant are so different. Do you think they have the same DNA?
- Write down any thoughts, curiosities, and questions about cells and life aaround this area.
- Think about interconnectedness. How are the parts of a plant connected to what you observe? How is the sky connected? How are you connected?
Sustainability and Cell Division
Sustainability refers to the ability of the environment and the living things it supports to endure into the future. Imagine for a moment that all living things on Earth are no longer able to reproduce—to make more of their own kind.
Imagine you are the last bear, eating the last berry bush. Or catching the last trout that moments earlier snapped up the last crayfish. Imagine this same scenario for every organism on the planet. If this were to happen, it wouldn't be long until every lifeform disappeared.
Reproduction ensures that organisms have a source of nutrients and energy to sustain their life processes. This is why the sustainability of living things depends on the reproduction of cells.
Imagine you are the last bear, eating the last berry bush. Or catching the last trout that moments earlier snapped up the last crayfish. Imagine this same scenario for every organism on the planet. If this were to happen, it wouldn't be long until every lifeform disappeared.
Reproduction ensures that organisms have a source of nutrients and energy to sustain their life processes. This is why the sustainability of living things depends on the reproduction of cells.
Continuity of Life
You already know that every cell comes from another cell. You also probably noticed we have to divide the things inside the cell before the cell itself can split in two. This brings us to the concept of continuity.
Biologists use this word to talk about how each species continues to exist over time, from one generation to another, and how their genetic material continues to exist. Individual organisms grow, develop, and die. However, a species continues to exist into the future only if its individual members produce offspring.
We all know about the Dodo extinction. Let's review it by watching the video below.
We all know about the Dodo extinction. Let's review it by watching the video below.
Just very recently, the company that claimed to have brought back the dire wolf also has plans to bring back the Dodo.
The way they do this is by manipulating the DNA of species that are related to these extinct animals until they get something that visually looks like the animal. Do you think this counts as continuity? What are some things that could go wrong with these new creatures, and why?
Can you Mix the DNA of Two Animals?
It is very difficult to do, but this has been done in labs before. The hope is that these studies can help humans develop self-healing abilities, fight disease and improve lives in general.
Sometimes, it is hard to figure out what specific place to modify. Scientists have developed a few glow in the dark animals by bathing very early cells of that animal with genetic material of bioluminescent animals.
Sometimes, it is hard to figure out what specific place to modify. Scientists have developed a few glow in the dark animals by bathing very early cells of that animal with genetic material of bioluminescent animals.
Why do you think this has to be done early in the development of the animal?
In your table groups, connect these three concepts:
Reproduction - Sustainability - Continuity
What kinds of connections could you make?
Transferring Genetic Material
Every species has its own strategies for reproduction. Flowers, for instance, often are shaped to attract specifically one species of animal. They have colours, shapes and scents that attract animals so that they can pick up and transfer pollen to other flowers.
Many animals have courtship rituals that enable sexually mature individuals of a species to become mating pairs.
Microbes such as bacteria reproduce on their own and form offspring by dividing in two... and then dividing again... and again... and again...
Despite all of these differences, there are just two basic ways that living things reproduce: asexually or sexually.
Asexual Reproduction: reproduction that requires only one parent and produces genetically identical offspring; the parent copies itself and the offspring receives the copy of the parent's genetic material.
Sexual Reproduction: reproduction that requires two parents. Each parent contributes to half of the offspring's genetic material. As a result, these new guys will be different when comparing to each parent, and also to each other (with rare exceptions, such as twins!)
Sexual Reproduction: reproduction that requires two parents. Each parent contributes to half of the offspring's genetic material. As a result, these new guys will be different when comparing to each parent, and also to each other (with rare exceptions, such as twins!)
In both asexual and sexual reproduction, the genetic material and the information it holds is passed on to the offspring. This information is contained within what is often called the molecule of life: DNA.
Every cell contains the same coded information, sometimes in a single helix, sometimes in a double helix, but the idea is the same: information is coded in long strings which are organized in different chromosomes, which together with all the other ones found in a particular nucleus, form the "recipe" of a whole organism.
DNA: The Strings that Organize All Life
An organism’s genetic material determines how it looks, functions, and in many cases, behaves. Genetic material carries these instructions in a long and complex molecule, called DNA, which is short for deoxyribonucleic acid.
Since the structure of the DNA is very small, the specific shape of the DNA has not been seen clearly; however, Watson and Crick developed the model we use today, which has been confirmed via xray experiments, molecular measuring and other lab experiments. DNA models looks like a ladder that was twisted in itself; this is why people call it a double-helix.
However, when you look at the DNA itself, the size of these molecules is so small, it is difficult to see them as clearly as the models. Below, a super coiled DNA sample, which only recently was imaged via an electron microscope.
All the DNA in the world consists of many copies of only four different chemical building blocks that are linked together, in specific and infinitely varied combinations. These building blocks are called nucleotides. The specific order in which they are linked together is called an organism’s DNA sequence. It is like a code that holds the genetic information of an organism.
The sides of the ladder are formed by sugar-phosphate combinations, which work as a backbone for the actual information strings. These sugar-phosphates are the same all the way down the ladder. Between the sugars, you need super strong bonds, which is where the phosphate comes in.
On the other hand, the bond between the bases needs to be pretty weak; little Hydrogen bridges ensure that the DNA can unravel itself during duplication or protein generation.
There are two Hydrogen bridges between Adenine and Thyamine, and three Hydrogen bridges between Guanine and Cytosine.
There are two Hydrogen bridges between Adenine and Thyamine, and three Hydrogen bridges between Guanine and Cytosine.
Notice that DNA has specific pairings:
Adenine always connects with Thyamine
Guanine always connects with Cytosine
Let's Play the DNA Game!!!
Each table should have posters with the two long strands, and missing bases. Pick a card; can you build a solution?
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Chromosomes Vs. Chromatin
On complex beings, the nucleus houses all the DNA. To fit into such small spaces, DNA molecules coil and compact into a condensed form called chromatin. When a cell is ready to reproduce, it is condensed even more into structures called chromosomes. When an organism reproduces, copies of its chromosomes, and therefore its DNA, are transferred to the offspring.
Forensics and DNA
An organism’s full DNA recipe is contained within each of its cells. That means the cells in your hands contain the full information of who you are. This is why DNA evidence has gathered a lot of attention in the forensics field, as it can prove the innocence of people who are in jail for crimes they did not commit. This can be gathered from a hair follicle, skin cells or even saliva.
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The Case of the Mismatched DNA | ||
Detective John Bolinha has recovered some new evidence on the case of the murder of Peppermint Patty. The murderer left a bloody fingerprint, and the material does not match the murder victim! Since the murdered entered the house through a broken window, it is likely they cut themselves while entering.
In a move that shocked the town, Mrs. Patty's teacher, Ms. Donovan, was arrested and put in jail for the murder. As an ex-pupil, detective Bolinha is counting on you to figure out a way to prove that Ms. Donovan is innocent!
Your task is to find matches for every DNA piece, reconstruct the DNA of the victim, and find out a way to prove that Ms. Donovan was just at the wrong place, at the wrong time.
Helpful Hints:
- Human DNA is usually exactly 23 pairs.
- Males are XY, while females are XX.
- The Y chromosome is very small.
Good luck detectives, and may the force be with you!
In a move that shocked the town, Mrs. Patty's teacher, Ms. Donovan, was arrested and put in jail for the murder. As an ex-pupil, detective Bolinha is counting on you to figure out a way to prove that Ms. Donovan is innocent!
Your task is to find matches for every DNA piece, reconstruct the DNA of the victim, and find out a way to prove that Ms. Donovan was just at the wrong place, at the wrong time.
Helpful Hints:
- Human DNA is usually exactly 23 pairs.
- Males are XY, while females are XX.
- The Y chromosome is very small.
Good luck detectives, and may the force be with you!
Open-Inquiry Project
Agricultural activities in B.C. include cattle ranching, dairy farming, poultry raising, and fish farming, as well as growing tree farming, poultry raising, and many types of ornamental fruits, vegetables, berries, grapes, and many types of ornamental flowers and shrubs. This success is completely dependent on continual reproduction of the plants and animals involved and following good practices for maintaining these natural resources.
In this investigation, you will research the role of reproduction in the sustainable development of an agricultural resource of your choice.
The chart below lists examples of agricultural products grown or raised in B.C. Choose one of these to investigate.
In this investigation, you will research the role of reproduction in the sustainable development of an agricultural resource of your choice.
The chart below lists examples of agricultural products grown or raised in B.C. Choose one of these to investigate.
FIRST STEP
Write out questions you have that could guide your research. Here are some examples to get you started:
- How is reproduction involved in developing and maintaining the crop or animal that you chose? What are some technologies that are used to help?
- How can Traditional Ecological Knowledge be applied to sustainable farming techniques?
- What, if any, issues are there? (Issues related to agriculture are often environmental and/or ethical, for example.)
SECOND STEP
Develop a research plan that you will follow. Other considerations include the following:
- What types of resources will have the most relevant information?
- Will you need to find print resources or use only online information?
- What resources are reliable? What makes a resource reliable?
- In what way can you use figures, graphs, and photographs to convey some of the information?
- Show Mrs. J the questions you have, and your plan of action, before speding time working on your project.
Third Step
Create up to three Powerpoint slides to share your findings.
On the fourth slide, consider the following:
The agriculture industry is more than just growing and raising plants and animals. It is also made up of all the people who contribute to the safe production, processing, and transportation of food products to consumers.
a) Come up with a list of 10 careers or jobs that are related to helping meet these needs.
b) What does this list tell you about the importance of the agriculture industry to the social and economic well-being of B.C.?
On the fourth slide, consider the following:
The agriculture industry is more than just growing and raising plants and animals. It is also made up of all the people who contribute to the safe production, processing, and transportation of food products to consumers.
a) Come up with a list of 10 careers or jobs that are related to helping meet these needs.
b) What does this list tell you about the importance of the agriculture industry to the social and economic well-being of B.C.?
LAB 3 - Extract DNA
from banana!
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Follow the instructions, checking the boxes as you go. Then, fill in the reflections!
How is your Comprehension?
Read each description below. Decide if it is an example of asexual reproduction or sexual reproduction.
a) A bacterial cell divides to form two new independent bacterial cells. (S / A?)
b) A female salmon lays thousands of eggs that will be fertilized by a male salmon. (S / A?)
c) A structure will form on the body wall of a Hydra, shown below. This structure will grow to a miniature adult form that breaks away to be an independent organism. (S / A?)
a) A bacterial cell divides to form two new independent bacterial cells. (S / A?)
b) A female salmon lays thousands of eggs that will be fertilized by a male salmon. (S / A?)
c) A structure will form on the body wall of a Hydra, shown below. This structure will grow to a miniature adult form that breaks away to be an independent organism. (S / A?)
The image below shows how scientists are using ear-shaped devices and a patient’s cells to develop an implant that can replace a human ear. Researchers hope this type of technology can be used to replace a variety of tissues and organs in people.
a) How does understanding cell reproduction allow scientists to generate organs and tissues in the laboratory?
b) Why do you think using a person’s own cell to make a new organ or tissue for them will increase the chance that their body will accept the transplant?
a) How does understanding cell reproduction allow scientists to generate organs and tissues in the laboratory?
b) Why do you think using a person’s own cell to make a new organ or tissue for them will increase the chance that their body will accept the transplant?
Which do you think plays a bigger role in the wide variety (diversity) of life on Earth: asexual or sexual reproduction? Explain why you think so.
