Genetics (S7L3)

Hello there again, this post will be specifically on the standard S7L3 which is genetics. Good luck and have fun with genetics!!!!!

Standard S7L3:
Students will recognize how biological traits are passed on to successive generations. 
Element A:
Explain the role of genes and chromosomes in the process of inheriting a specific trait. 
Element B:
Compare and contrast sexual and asexual reproduction in organisms.
Element C:
Recognize that selective breeding can produce plants or animals with desired traits. 

Genetics- The study of heredity and the variation of inherited characteristics.
Genetics has to be my favorite standard of them all. (Here is the better version) Genetics is the process of trait inheritance from parents to offspring, including the molecular structure and function of genes, gene behavior in the context of a cell or organism (e.g. dominance and epigenetics), gene distribution and variation and change in populations. Given that genes are universal to living organisms, genetics can be applied to the study of all living systems, including bacteria, plants, animals, and humans. Here I will be talking about selective breeding, asexual reproduction, sexual reproduction, genes and chromosomes. Good luck and I hope you have fun!!!!!!

Selective breeding- Selective breeding (also called artificial selection) is the process by which humans breed other animals and plants for particular traits. Typically, strains that are selectively bred are domesticated, and the breeding is normally done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties, cultigens, or cultivars. The offspring of two purebreed animals but of different breeds is called a crossbreed, and crossbred plants are called hybrids.
There are two approaches or types of artificial selection, or selective breeding. First is the traditional “breeder’s approach” in which the breeder or experimenter applies “a known amount of selection to a single phenotypic trait” by examining the chosen trait and choosing to breed only those that exhibit higher or “extreme values” of that trait. The second is called “controlled natural selection,” which is essentially natural selection in a controlled environment. In this, the breeder does not choose which individuals being tested “survive or reproduce,” as he or she could in the traditional approach. There are also “selection experiments,” which is a third approach and these are conducted in order to determine the “strength of natural selection in the wild.” However, this is more often an observational approach as opposed to an experimental approach.
In animal breeding, techniques such as inbreeding, linebreeding, and outcrossing are utilized. In plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his book, On the Origin of Species. The first chapter of the book discusses selective breeding and domestication of such animals as pigeons, cats, cattle, and dogs. Selective breeding was used by Darwin as a springboard to introduce the theory of natural selection, and to support it.
The deliberate exploitation of selective breeding to produce desired results has become very common in agriculture and experimental biology.
Selective breeding can be unintentional, AKA resulting from the process of human cultivation; and it may also produce unintended – desirable or undesirable – results. For example, in some grains, an increase in seed size may have resulted from certain ploughing practices rather than from the intentional selection of larger seeds. Most likely, there has been an interdependence between natural and artificial factors that have resulted in plant domestication.

Asexual reproduction- asexual reproduction is a mode of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it is reproduction which almost never involves ploidy or reduction[disambiguation needed]. The offspring will be exact genetic copies of the parent, except in the specific case of automixis. A more stringent definition is agamogenesis which is reproduction without the fusion of gametes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaebacteria, eubacteria, and protists. Many plants and fungi reproduce asexually as well.

While all prokaryotes reproduce asexually (without the formation and fusion of gametes), mechanisms for lateral gene transfer such as conjugation, transformation and transduction are sometimes likened to sexual reproduction. A complete lack of sexual reproduction is relatively rare among multicellular organisms, particularly animals. It is not entirely understood why the ability to reproduce sexually is so common among them. Current hypotheses suggest that asexual reproduction may have short term benefits when rapid population growth is important or in stable environments, while sexual reproduction offers a net advantage by allowing more rapid generation of genetic diversity, allowing adaptation to changing environments. Developmental constraints may underlie why few animals have relinquished sexual reproduction completely in their life-cycles. Another constraint on switching from sexual to asexual reproduction would be the concomitant loss of meiosis and the protective recombinational repair of DNA damage afforded as one function of meiosis.

 Sexual Reproduction- Sexual reproduction is a process that creates a new organism by combining the genetic material of two organisms. It occurs both in eukaryotes and prokaryotes in multicellular eukaryote organisms, an individual is created anew; in prokaryotes, the initial cell has additional or transformed genetic material. In a process called genetic recombination, genetic material (DNA) originating from two different individuals (parents) join up so that homologous sequences are aligned with each other, and this is followed by exchange of genetic information. 
Sexual reproduction is the primary method of reproduction for the vast majority of macroscopic organisms, including almost all animals and plants. The evolution of sexual reproduction is a major puzzle. The first fossilized evidence of sexual reproduction in eukaryotes is from the Stenian period, about 1 to 1.2 billion years ago. There are two main processes during sexual reproduction in eukaryotes: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the restoration of the original number of chromosomes. During meiosis, the chromosomes of each pair usually exchange genetic information to achieve homologous recombination. Evolutionary thought proposes several explanations for why sexual reproduction developed and why it is maintained. These reasons include fighting the accumulation of deleterious mutations, increasing rate of adaptation to changing environments, dealing with competition (see the tangled bank hypothesis) or as an adaptation for repairing DNA damage and masking deleterious mutations. The maintenance of sexual reproduction has been explained by theories that work at several different levels of selection, though some of these models remain controversial. New models presented in recent years, however, suggest a basic advantage for sexual reproduction in slowly reproducing, complex organisms, exhibiting characteristics that depend on the specific environment that the given species inhabit, and the particular survival strategies that they employ.

Genes and chromosomes- 
Genes- A gene is the molecular unit of heredity of a living organism. It is used extensively by the scientific community as a name given to some stretches of deoxyribonucleic acids (DNA) and ribonucleic acids (RNA) that code for a polypeptide or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains. Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. All organisms have genes corresponding to various biological traits, some of which are instantly visible, such as eye color or number of limbs, and some of which are not, such as blood type, increased risk for specific diseases, or the thousands of basic biochemical processes that comprise life.
Chromosomes- A chromosome is a structure of DNA, protein, and RNA found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions. Chromosomal DNA encodes most or all of an organism's genetic information; some species also contain plasmids or other extrachromosomal genetic elements.

Well, that's basically everything you need to know about genetics!! Have fun learning and studying!

I got most of the info from wiki
I got the pictures from google images
I got the videos from youtube.com 
-Andy Iyabor