Steps To Be Followed during a Scientific Discovery

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Hypotheses-Testable statements that potentially explain specific phenomena observed in the nature world. Theory-A set of hypotheses that have been rigorously tested and validated, leading to their establishment as generally accepted explanation of specific phenomena The steps of scientific method.1 indentifying the problem based on some earlier observations. 2 starting the hypothesis 3 collecting the data ( observations) 4 testing the hypothesis: rejection or acceptance. A good hypothesis( narrow specific testable falsifiable.Usually contains a prediction.) Why biologist view evolution as a theory And a fact( evolution as a fact- various lab animals , from fruit flies and bacteria to nematode worms and zebrafish can be observed to evolve after exposure to mutagens or interference with their genes.) Charles Darwin’s Major contributions: he wasn’t the first to conceptualize natural selection but he showed how it operated in nature; he also advanced the related idea that all organisms had descended from a common ancestor. Evolution: heritable change in allele frequencies in a population over time. 4 major forces of evolutionary change are: 1 natural selection(could operate only on variation that already existed in a population. 2mutation (a random change in a gene or chromosome, creating a new trait that may be anemia advantageous deleterious, or neutral in its effects on organism. 3.gene flow admixture or exchange of alleles between two populations. 4.genetic drift (The random change in allele frequency from one generation to the next with greater effect in small populations. ( 1.pole bear 2fruit flies 3 sickle-cell 4 fish.) Meiosis play a significant role in evolution ( it’s a source of individual genetic variation without that variation, natural selection can’t take place) How individual variation comes – random assortment (4 possible combinations AB Ab aB ab.) Crossing-over (The process by which partially wrap around each and exchange genetic information during meiosis) mutation(). DNA functions 1serve as a template for transcription 2 serve as a template for DNA replication 3 participate in control of gene expression. Aids resistance positive too many hairs of human negative fruit flies neutral mutation. Dna structured ( in 3 letter “words” made up of the chemicals ATCG which pair up in a predictable pattern. A&t c&g) molecular structure. NA is basically a long molecule that contains coded instructions for the cells. How it works for RNA. The now-exposed bases in the DNA molecule serve as a single template for ribonucleic acid RNA. Only one of the two DNA strands serves as the temple for the production of RNA. This strand attracts free- floating RNA nucleotides. The strand of RNA now called messenger RNA, mRNA then splits off from the DNA template, leaves the nucleus, and moves into the cytoplasm. RNA structured ( it is a single stranded molecule, which links up to its complementary opposites in DNA with one difference: U or uracil substitutes for T or thymine) 1. transcription( nucleus) parental strand of DNA unzips, exposing two daughter strands of DNA. Free-floating RNA nucleotides match one exposed daughter strand of DNA. The strand of messenger RNA (mRNA) moves out of the nucleus and into the cytoplasm. 2. Translation( cytoplasm) The mRNA attaches to a ribosome in the cytoplasm. Triples of transfer RNA( tRNA), with exposed bases and each carrying an amino acid specific to its set of three bases, recognize and bind with complementary base pairs of mRNA. The amino acids, linked by peptide bonds, form a chain called a polypeptide. The protein forms, either as a single polypeptide or as a multiple polypeptides bound together. The Law of segregation or sorting- Mendel’s experiments with garden peas showed that when a male&female mate, each parent contributes an allele to the offspring. This was a revolutionary discovery. In humans ( and any other sexually-reproducing organism) it meant that half your genetic...
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