Download Emily Luetschwager Science 7, Hr 7 Long Term Project Research

Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
Plant Biology:
Plant biology is the study of the life of plants. Plants are living things. They have all the
six traits of life: they have cells, they grow and develop, they have DNA, they sense and respond
to change, they reproduce, and they use energy. Plants start from seeds. Each seed contains a tiny
plant waiting to germinate. In the early life of a plant, the small seedling relies on the food stored
within itself to get energy. Once the plant develops, it gets its energy through the process of
photosynthesis. Photosynthesis is the process by which plants make food from light, water,
nutrients, and carbon dioxide. Also during photosynthesis, plants release oxygen to the air. When
the plant is first starting to grow, it pushes its roots down into the soil, that way the plant can
easily access water and minerals. In addition while the roots are getting pushed down, the stem
and the new leaves are getting pushed up to the light. The germination stage ends as soon as the
plant pushes through the surface of the ground.
Plants are producers, which means that they make their own food. Plants need several
different things to make food, those things are: chlorophyll, light, carbon dioxide, water,
nutrients and minerals. Chlorophyll is a green pigment found in the cells of plants. Chlorophyll
colors the leaves green and produces the food through the process of photosynthesis. Light,
carbon dioxide, water, nutrients and minerals are important because those are the things that the
plant gets its energy to make food from.
Plants must go through pollination in order to reproduce. Pollination starts in the flower
of a plant. The male part of the flower is called the stamen. The stamen produces the sticky
powder we know as pollen. The flower of a plant also contains a female part called the pistil. The
top of the pistil is the stigma which is often sticky. Seed will eventually be made at the bottom of
the pistil in the ovary. In order for the plant to be pollinated pollen has to be transferred from the
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
stamen to the stigma. There are two different types of pollination, self-pollination and crosspollination. Self-pollination is when pollen from a plant’s stamen is transferred to its own stigma.
Cross-pollination is when pollen from a plant’s stamen is transferred to another plant of the same
species’ stigma. This type of pollination often produces stronger plants. Pollen gets transferred
from one plant to another either by animals or by the wind. Pollen is transferred by animals by
pollen getting stuck on the animal while feeding. Then the animal goes to another flower and the
pollen comes off there. Pollen can be moved by the wind as well. Some plants have longer
stamens and pistils that way the wind can easily move the pollen. Once a flower is pollinated it
travels down the pistil and enters the ovary. The male cells (also known as pollen), fertilizes the
eggs, which then develop into seeds. The seeds become a part of a pod after the petals wilt and
fall away. One last part about plant biology is that plants do many things to help humans and
other animals out too. Plants give us food, oxygen, and shelter. Without plants nothing would be
able to live on Earth.
Genetics:
Genetics is a branch of biology that studies heredity and inherited characteristics.
Heredity is the passing on of traits from one organism to another. Heredity traits are determined
by specific genes located in a cell. Within DNA, there are many different genes that exist for
different purposes. There are genes for hair color, for height, for weight, etc. There are some
variations of a gene that relate to the same trait. These variations are called alleles. Every
organism carries two genes for each trait. One gene is from the father’s sperm and one from the
mother’s egg. One of these genes is more dominant than the other. The other allele is called a
recessive allele, and is masked by the dominate allele.
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
R.C. Punnett, the British Biologist, developed a method to show the concept of dominate
and recessive alleles. This method is called the Punnett Square. In the Punnett Square picture
graph, dominate alleles are show by a capital letter, and recessive alleles are shown by the same
letter in lowercase. So for example, if the mother has a dominate allele, T, and a recessive allele,
t, and the father has to recessive alleles, t, there are two different combinations of height that the
offspring could be. The offspring could be a Tt, a tall hybrid, or a tt, which is short. So, there is a
50% chance of the child being tall or being short. There is a difference between being a tall
hybrid and a pure tall. If the symbols line up to being TT, that means you are a pure tall. If the
symbols combine to be Tt, you would be a tall hybrid. If the symbols end up tt, you are short.
You can make a Punnett Square with two or more traits as well. These types of Punnett Squares
are an example of the Law of Independent Assortment. The Law of Independent Assortment
means that one trait doesn’t affect another. An example would be that having blonde hair doesn’t
mean you a have good eyesight, so the traits are independent of one another. Sometimes, there
aren’t recessive and dominant alleles. These alleles are called co-dominant alleles. An example
of co-dominant alleles would be skin color. If one parent is fair-skinned and the other is darkskinned, the offspring would be a mix of the two.
When an individual organism reproduces, the cells segregate through a process of
meiosis. Meiosis is similar to mitosis, but meiosis involves the sex/reproduction cells, sperm and
egg. Reproduction cells have 23 chromosomes. This is called a haploid, which means “one set”.
Now, when the cells combine they form a diploid, which means “two sets”. In the first stages of
meiosis the chromosomes are copied and they divide normally, just like in mitosis. The next step
is different from mitosis though, the chromosomes will start to cross-over. When the
chromosomes are crossing-over, some of the paired up chromosomes will switch genetics data.
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
This is how the Punnett Square is involved. The Punnett Square simply shows the switching of
the genetic data, so that both parents’ genes will be present in the offspring. Instantly after the
cells divide, they will divide again without copying the chromosomes, creating four reproduction
cells, each with 23 chromosomes. That is how genes are transferred from one organism to
another.
Plant Genetics:
Plant genetics is the study of heredity in plants, and how various plants pass on traits.
Plant cells have chloroplasts in them instead of mitochondria. These chloroplasts have their own
DNA, which will be passed on to the next generation. The male or female reproduction cells
have their own alleles which decide the traits of the plant. For example, a pea plant would have
an allele for flower color, either purple or white. You can figure out what color the flower would
be by using a Punnett Square. If both parents have purple flowers, the offspring would have a
purple flower. If one parent has a white flower and one ahs a purple flower, the offspring would
have a 50/50 chance of either having a purple or a white flower. So, it all depends on what the
dominant and recessive alleles are to decide the different traits of the plant.
According to the principle of individual assortment, different pairs of alleles are passed to
offspring independently of each other. This means that the color of the flower of a pea plant
won’t affect the color of the pea seeds. This basic principle was discovered by Gregor Mendel.
Mendel studied how plants reproduced and how traits were passed on from one generation to the
next. Mendel started his experiments with pea plants because they can self-fertilize and they
grow very quickly. Mendel focused on 7 characteristics of the pea to study: texture, color of the
peas, color of the outer coat of the peas, shape of full-grown pea pod, color of unripe pea-pod,
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
position of the flowers on the stem, and length of the stem. After two years of breeding the plants
to make sure they are pure-breeders, Mendel started to cross-breed the plants. He would cross the
plants with very different characteristics, for example: tall and short, yellow and purple, etc. He
then realized that most of the offspring from the tall and short plants were tall, only 1 compared
to every 3 plants was short. He noticed that many plants had similar ratios like this. He
experimented for 8 years figuring out heredity in plants. He finally completed his studies in
1863, and in 1865 he presented his idea to the Nation History Society in Brunn. Mendel then
published his results in their journal, Transactions of the Brunn National History Society.
Without Mendel’s work, we wouldn’t have found out the basic information about heredity in
plants.
Plant Breeding:
Plant breeding is the science of changing genetics in plants. It is usually done to get the
characteristics of plants to what you want them to be. Plant breeding has been practiced for
thousands of years, by many different types of people as well. Gardeners, farmers, and
professional breeders will all use plant breeding. Modern plant breeders use techniques of
molecular biology to select and insert the traits into the plant. This method is known as
Molecular Breeding or Genetic Modification.
In genetic modification, the scientists will either add a specific gene or take out a gene
using RNAi. In order to genetically modify a plant, the scientist must design a genetic construct,
which is like a blue-print telling then what genes they are going to take out and what genes they
are going to add. To accomplish this task, a promoter must drive a termination sequence to stop
the old gene and to add the new genes to the plant. Once the plants are transformed, they will
grow on antibiotics, because otherwise they will die. Most of the modern day plant breeders will
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
put a resistance to insect pests into the plant, nor a gene that could make a variety of the plant to
grow in a different season. Some other motives that scientists wish to accomplish from plant
breeding are: cold tolerance, improvement of quality, changing maturity duration, dormancy
(failure to fully develop a seed), and disease resistance.
There are some concerns with plant breeding though. Some scientists say that when you
insert certain genes into the plant, other genes may be ignored or forgotten about, which could
lower their nutritional value. Otherwise, plant breeding is a way that scientists have developed to
make a better crop and grow crops faster without getting eaten by insects.
Identification of Alternate Dwarfing System in Wheat:
The process of the alternate dwarfing system in wheat is also known as the Green
Revolution. The Green Revolution was after the 1960s, referring to the enormous increases in
grain yields. This all happened because of the introduction of new varieties of wheat and rice,
which were discovered by Norman Borlaug. Borlaug introduced dwarfing genes to wheat. These
genes gave wheat a shorter, stronger stem that helped the plant survive in the wind and rain. This
method was soon recognized and large commercial wheat farmers started to use this gene. The
wheat plant is protected by herbicides that way it doesn’t have to fight with weeds for the sun.
The genes that are associated with the dwarfing system in wheat are known as Reduced Height
(Rht) genes. These genes are either dominant or semi-dominant; assuring that the plant will have
a shorter and stronger stem. Two genes that are used in numerous commercial wheat varieties are
Rht-B1b and Rht-D1b.These two genes affect the growth of the plant making it shorter. There is
also a very severe dwarfing gene for wheat known as Rht-B1c. This gene will make the wheat
smaller than what the two genes used in commercial farming would. Overall, the method of the
Emily Luetschwager
Science 7, Hr 7
Long Term Project
Research
alternate dwarfing system of wheat helps the wheat withstand the natural elements of wind and
rain, which helps increase the wheat production, therefore, feeding more families.
The Genes Involved in the Reproduction of Soybean:
Soybean reproduces through eight stages. During the first stage the soybean begins to
start flowering. The plant will usually have at least one flower. The plant will then go into the
full flowering stage where there will be an open flower on one of the two uppermost nodes. After
the soybean gets the full flower, a pod will begin to form on one of the four highest nodes. These
beginning pods are 3/16th of an inch long. The pod will then fully grow and become 3/4th of an
inch long. After the pod is at its full length, a seed will start to develop inside of it. The next
stage is the full green seed, which fills the pod capacity. The plant will then begin its maturity
when one of the normal pods on the main stem has reached the mature pod color. Lastly, the
plant will be fully mature when 95% of the pods have reached the full mature color.
One of the genes that controls the flowering process in soybean is the gigantea gene. The
gigantea specifically controls the flowering time in the soybean plant. This gene is one of the
most important genes in the process of reproduction of the soybean plant. Without this gene, a
soybean plant wouldn’t flower at the proper time and would develop healthy beans, which would
affect many people worldwide. In summary, the gigantea gene is very important when it comes
to the reproduction of the soybean.
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