Blueprint+of+Life

Blueprint of Life Please complete the table with your nominated scientist. Isabelle you can do Pasteur and Koch! oops I did Lamarck already. History of genetics

-The organisms who die as a consequence of competition due to lack of resources were not totally random, Darwin found that those organisms more suited to their environment were more likely to survive. -This resulted in the well known phrase //survival of the fittest//, where the organisms most suited to their environment had more chance of survival if the species falls upon hard times - These genomes that enabled them to survive are then passed down to offspring ||< Darwin's finches are an excellent example of the way in which species' gene pools have adapted in order for long term survival via their offspring. Their beaks have evolved over time to be best suited to their function. For example, the finches who eat grubs have a thin extended beak to poke into holes in the ground and extract the grubs. Finches who eat buds and fruit would be less successful at doing this, while their claw like beaks can grind down their food and thus give them a selective advantage in circumstances where buds are the only real food source for finches. || - chromosomes occur in distinct pairs - during meiosis, chromosomes number of a cell is halved, and only during fertilisation is the full chromosome number restored || Concluded that chromosomes are the carriers of hereditary units (i.e. genes)
 * < Scientist/s ||< Description ||< Contribution ||< Experimental Evidence ||
 * < Jean-Baptiste Lamark ||< (1809) proposed one of the first theories of evolution. His theory stated that both animals and humans evolved through a natural process, and change can about through the use of particular organs; these changes were then inherited. ||< Proposed one of the first theories of evolution. ||< Eg the giraffe has a long neck as its ancestors stretched their necks to reach food and gradually their necks got longer through use. ||
 * < Gregor Mendel ||< (1860s) examined seven characteristics found in garden peas (flower colour, flower position, seed colour, seed shape, pod shape, pod colour and stem height) he first cross fertilised two true breeding plants for one characteristic and then self fertilised or cross fertilised to produce a second generation ||< formulated principles of genetics, discovering recessive and dominant factors in the ration 3:1 (dominant : recessive) ||< when two true breeding plants were beng crossed, only the dominant factor appeared in the first generation. the recessive factor appeared in the second generation ||
 * < Darwin and Wallace ||< Charles Darwin and Alfred Wallace independantly arrived at evolution as a result of natural selection. Darwin gathered evidence after sailing on the HMS //beagle//.//The origin of species// was a book that was published that included evidence of natural selection. ||< Proposed the theory of natural selection:
 * Walter Sutton || From observations of meiosis in grasshoppers revealed that;

This idea that genes were located on chromosomes became known as the Sutton-Boveri chromosome hypothesis. || Observations of grasshopper cells during meiosis showed that the number of chromosomes is halved- only once fertilised is the full chromosome number restored. || . He studied the behaviour of the cell nucleus and chromosomes during meiosis and after fertilisation. These experiments showed that the nucleus of a sperm and egg each contribute the same amount-50% of chromosomes to the zygote-the fertilised egg-, making a connection between chromosomes and heredity || - Complete set of chromosomes is needed for normal development - Inheritance factors are found on chromosomes within the nucleus. chromosomes are the carriers of heredity - more hereditary factors than chromosomes, so many factors are determined by one chromosome || When an egg, whose nucleus has been removed was fertilised with a sperm, sea urchin larvae resulted in characteristics only of the male - also only had half the normal chromosome number and were smaller ||
 * Theodor Boveri || 1896 and 1904 carried out experiments on sea urchin egg

-looked at crosses, using Mendelian sequences, between red and white eyed flies. these results could not be accounted for dy mendelian crosses || eye colour gene on x chromosome with no corresponding gene on y. Therefore sex linked -Hereditary factors can be exchanged between individuals during meiosis -Gave greater understanding of how genes are arranged on chromosomes || - 3 crosses using punnet squares to give 3 generations
 * Thomas Hunt Morgan || -worked on fruit flies (drosphila melanogaster)

1.white eyed xred eyed = F1- 100% red eyed

2.female (Rr) x male (R) = F2- 80%red, 20% white

3.female (Rr) x male (r) = F3-50%white, 50% red ||
 * Beadle and Tatum || ====== George Beadle and Edward Tatum during ======

won the Nobel Prize in 1958.
|| Proposed the theory of "one gene one enzyme" || - X-rays on Neurospora crassa - Mutant Eyes of Drosiphila

More Info @: __http://www.emc.maricopa.edu/faculty /farabee/biobk/biobookprotsyn.html__ || about its chemical and physical nature , but Watson believed that its function could not be understood fully until its structure was known. Crick and Watson used the results from previous studies a nd X-ray diffraction data from Maurice Wilkins and Rosalind Franklin to help them determine DNA's molecular structure. By 1953 they had built a model which incorporated all known features of DNA, and proposed the double helix structure which is commonly referred to as the Watson-Crick model of DNA. || Created the well known model of the structure of DNA. || X-ray crystallographers || Do you know??? disease and which ones caused disease by the use of his postulates. || His postulates meant that people were able determine which organisms caused which diseases. || Experimented on Anthrax and Tuberculosis to work out his postulates. 1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy animals 2. The microorganism must be isolated from a diseased organism and grown in pure culture 3. The cultured microorganism should cause disease when introduced into a healthy organism 4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent. ||
 * Watson and Crick || Studies of DNA had revealed much
 * Franklin and Wilkins || Emilia ||  ||   ||
 * Eldridge and Gould || Punctuated equilibrium – species undergo rapid change followed by stasis or little change with speciation occurring almost instantaneously. || Gave evidence to support the theory of punctuated equilibrium (cf gradual evolution Darwin). || Some elements of the fossil record supports this (missing links in record). cf gradual evolution as seen in horse hooves and teeth. ||
 * Pasteur || Louis Pasteur made invaluable contributions to the understanding of infectious disease. He refuted the theory of spontaneous generation and proposed the germ theory of disease (the theory that proposes microorganisms are the cause of many diseases.) Pasteur uncovered the relationship between microorganisms and disease. || He disproved the theory of spontaneous generation (widely held at that time - the belief that life can arise from non-living matter) and showed micro-organisms came from pre-existing micro-organisms. || To support this theory, he carried out his famous 'swan-necked flask' experiments, which involved boiling meat broth in flasks that had long-drawn-out necks that were not sealed. As they cooled, the air was drawn in from the outside, and any microorganisms present in the air did not reach the broth as they were trapped in the narrow neck and curve of the glass. No bacterial or fungal growth was observed in these flasks, however, bacterial growth was observed in the flasks which did not have the 'swan-necks', and were therefore exposed to the air. ||
 * Koch || He was able to show that an organism caused
 * 5.1 Impact of reproductive technologies on genetic composition** also read and summarise p218-223
 * 5.1 Impact of reproductive technologies on genetic composition** also read and summarise p218-223

Humans have domesticated crops and animals over the years and in doing so have artificially selected preferred characteristics e.g. high milk yield in cows or high grain yield in wheat. Individuals with less desirable characteristics are not allowed to reproduce. In this way, humans have altered the genetic composition of populations.

Other reproductive technologies have been developed to speed up these changes.

__Artificial insemination__ is the fusion of sperm and ova without the normal mating process e.g. sperm from a bull that is a good meat producer may be used to inseminate hundreds of cows. Sperm can be frozen and transported over large distances and can be placed in the females’ body when she is physically receptive. Initially this could be seen as increasing genetic diversity, as semen form anew bull is introduced into the population. However, over time, this process can reduce genetic diversity because the union of sperm and ova is no longer random. There would be a greater percentage of genes from the one bull in the population.

__Artificial pollination__ The genetic composition of a population can be rapidly changed to suit the breeder. Pollen from the stamen of one plant can be dusted by hand onto the stigmas of another.

__Cloning__ Cloning produces individuals that are genetically identical. Simple methods include taking cuttings so that breeders can make copies of plants with desirable characteristics. Tissue culture is a more complex cloning method where a few cells of an organism are grown in a culture medium to produce mature organisms that are genetically identical. Nuclear transfer involves the transfer of a nucleus from a cell of one animal into an egg cell of another organism that had its nucleus removed. An electric current causes the nucleus and cell to fuse. The egg is incubated and the embryo implanted into a different sheep (a surrogate mother). The offspring is genetically identical to the organism that provided the original nucleus. This website will help you with Part B question 2. Also see biotechnology website on links page http://www.newscientist.com/article/dn3393-dolly-the-sheep-dies-young.html Websites BOL media type="youtube" key="iCL6d0OwKt8" height="325" width="629"
 * 5.4 Read pages 223-225 and nswer the questions on page 225.**