March 2012 Archives

Assignment #3

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     Puberty is the process of physical changes by which a child's body matures into an adult body capable of sexual reproduction to enable fertilization.  It is initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the sexual organs.
     Coming-of-age ceremonies are held when a child or youth becomes recognized as an adult for the first time. These rituals were and are found in almost all aboriginal societies. In modern times, the transition into adulthood often happens without a formal, public celebration. Judaism: Girls reach the status of Bat Mitzvah on their 12th birthday. Boys achieve Bar Mitzvah on their 13th birthday. They are then recognized as adults and are personally responsible to follow the Jewish commandments and laws. Australia, New Zealand and many other countries: A a party called "The Twenty First" is often held to celebrate a youth having come of age. It is held on their 21st birthday.
     During this period, also in response to rising levels of estrogen, the lower half of the pelvis and thus hips widen (providing a larger birth canal). Fat tissue increases to a greater percentage of the body composition than in males, especially in the typical female distribution of breasts, hips, buttocks, thighs, upper arms, and pubis. Progressive differences in fat distribution as well as sex differences in local skeletal growth contribute to the typical female body shape by the end of puberty. On average, at 10 years, girls have 6% more body fat than boys.
     By the end of puberty, adult men have heavier bones and nearly twice as much skeletal muscle. Some of the bone growth (e.g. shoulder width and jaw) is disproportionately greater, resulting in noticeably different male and female skeletal shapes.

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 Gregor Mendel Studied:

1. flower color is purple or white 2. flower position is axil or terminal 3. stem length is long or short 4. seed shape is round or wrinkled 5. seed color is yellow or green 6. pod shape is inflated or constricted 7. pod color is yellow or green.



One of two principles of heredity first formulated by Gregor Mendel, founded on his experiments with pea plants and stating that the members of a pair of homologous chromosomes segregate during meiosis and are distributed to different gametes.

One of two principles of heredity first formulated by Gregor Mendel, founded on his experiments with pea plants and stating that the members of a pair of homologous chromosomes segregate during meiosis and are distributed to different gametes.

Heredity and Genetics

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Heredity is the passing on of characteristics from one generation to the next. It is the reason why offspring look like their parentsThe process of heredity occurs among all living things including animals, plants, bacteria, protists and fungi. Through heredity, living things inherit traits from their parents. Traits are physical characteristics.



Genes are strung together to form long chains of DNA in structures known as chromosomes. Genes are composed of deoxyribonucleic acid (DNA ). DNA replicates by separating into two single strands, each of which serves as a template for a new strand.

Chromosome, the microscopic, threadlike part of the cell that carries hereditary information in the form of genes. Mendel disproved the blood theory. He showed (1) that heredity is transmitted through factors (now called genes) that do not blend but segregate, (2) that parents transmit only one-half of the genes they have to each child, and they transmit different sets of genes to different children, and (3) that, although brothers and sisters receive their heredities from the same parents, they do not receive the same heredities (an exception is identical twins).

Science 90 Assignment 1

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0720-gregor-mendel_full_600.jpg Gregor Mendel

  1. Mendel was able to selectively cross-pollinate purebred plants with particular traits and observe the outcome over many generations. This was the basis for his conclusions about the nature of genetic inheritance.
  2. Mendel was famous for working with pea plants. He breeded different kinds of pea plants to get certain kinds of colors of peas.
  3. Mendel's findings allowed other scientists to simplify the emergence of traits to mathematical probability  
  4. Mendel found that the inheritance of each trait is determined by "units" or "factors" that are passed on to descendents unchanged these units are now called genes
  5.  Mendel's work was largely ignored until sixteen years after his death
  6.  None of Mendel's experimental notebooks have survived. It is thought the notebooks were burned by the monks after Mendel's death.
  7.  Mendel studied mathematics, physics, ethics, philosophy and pedagogics at Olomouc University in 1841
  8.  These two principles of inheritance, along with the understanding of unit inheritance and dominance, were the beginnings of our modern science of genetics.
  9. Mendel noticed that the plants' traits did not blend together: a pea plant with yellow pods cross-pollinated with one with green pods plant did not result in yellowish-green pods, as would have been expected 
  10. Mendel died in 1884, and just sixteen years later his work was rediscovered independently by scientists Hugo de Vries and Carl Correns.


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