Genetic Variation

Random Fertilization

Asexual Reproduction

reproduction without the fusion of gametes

Sexual Reproduction

process in which genetic material from two parents combines and produces offspring that differ genetically from either parent

Gregor Mendel

formulated the laws of heredity based on his careful breeding experiments on garden pea plants. “father of Genetics” Crossing Over

exchange of genetic material between homologous chromosomes during prophase I of meiosis

Fredrick Griffith

Conducted one of the first experiments suggesting that bacteria are capable of transferring genetic information through a process known as transformation.

In this experiment, bacteria from the III-S strain were killed by heat, and their remains were added to II-R strain bacteria. While neither alone harmed the mice, the combination was able to kill its host. Griffith was also able to isolate both live II-R and live III-S strains of pneumococcus from the blood of these dead mice. Griffith concluded that the type II-R had been "transformed" into the lethal III-S strain by a "transforming principle" that was somehow part of the dead III-S strain bacteria.

Transformation

DNA that is transferred from one individual to another in genetic transformation

Conjugation

temporary union of two single cells (or hyphae in fungi) with at least one of them receiving genetic material from the other: the bacterial equivalent of sexual reproduction. A fragment of the DNA from one bacterium is passed along a thin tube, the pilus, into another bacterium.

Natural Selection

Natural selection is the result of the interactions between genetic variations in a population and the environment. The environment determines which variations are more favorable. More favorable traits are thereby passed on to the population as a whole

In genetic variation, the genes of organisms within a population change. Gene alleles determine distinct traits that can be passed on from parents to offspring. Gene variation is important to the process of natural selection. The genetic variations that arise in a population happen by chance, but the process of natural selection does not.

Random Assortment

Random assortment takes place within single parent during meiosis but before fertilization follows and individual gametes created through meiosis have one set of chromosomes. During fertilization the zygote basically inherits a mix of all four of its grandparents.

The random combination of chromosomes resulting from pairing up 1 of the 8.4 million possible chromosome combinations of a sperm with 1 of the 8.4 million possibly chromosome combinations of the egg (due to independent assortment of chromosomes during Meiosis. This comes out to about 70 trillion combinations, which does not even factor in the crossing over of genetic material during Meiosis.

Prokaryotes

Eukaryotes

Prokaryotes are organisms without a cell nucleus, or indeed any other membrane-bound organelles, in most cases unicellular

A eukaryote is any organism whose cells contain a nucleus and other structures enclosed within membranes.

Mutations

A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.

Transduction

The transfer of genetic material from one organism (as a bacterium) to another by a genetic vector and especially a bacteriophage.

Viruses

(Bacteriaphage)

A virus is an infectious agent that occupies a place near the boundary between the living and the nonliving. It is a particle much smaller than a bacterial cell, consisting of a small genome of either DNA or RNA surrounded by a protein coat. Viruses enter host cells and hijack the enzymes and materials of the host cells to make more copies of themselves. Viruses cause a wide variety of diseases in plants and animals, including AIDS, measles, smallpox, and polio.

Prokaryotesreproduce asexually using mitosis

reproducingcells usingmitosis for repairor replacement

Creating Offspringthat differsgenetically

Viruses invade bothprokaryotes and eukaryotes using transduction tohijack their cell so that it canreproduce

Method of invasionso that a Viruscan reproduce

Viruses can cause mutations

Both made important discoveriesthat advanced understandingof genetics.

Introductory to Sexual ReproductionMendel worked out how traits canbe recessive Mendel studied how through sexual reproduction

genes could be passed on sometimes skipping generations and showing up later on in a second or third generation.

He also relised that this reproductionwas random but occured in a predictable ratio.