References

Talktalk.co.uk

Wikipedia.org

about.com

chemmybear.com

dictionary.reference.com

britannica.com

biology-online.org

 yieldengineering.com

zoology.ubc.ca

learner.org

library.thinkquest.org

bcb.uwc.ac.za

emc.maricopa.edu

nature.com

science.jrank.org

sciencedaily.com

Trait

Eye color is trait.

A trait is an observable feature of an organism. A genotype genetically determines the outcome of the trait and the phenotype physically displays it. The information is contained in the DNA, which can then either follow the processes of transcription and translation by transferring to mRNA, base-pairing, and forming protein molecules or it can travel from cell to cell. The final products of the cells are released into the tissues and affect the makeup of the organism. Examples: eye color, hair color, and body shape.

Population

A population of Babie dolls that live in my house (and Lamby).

A population is a group of one type of species living in one geographical area. The species must be capable breeding with one another and live near each other to be defined as a population. A population undergoes three phases throughout its lifespan: growth, stability, and decline. It will both increase and decrease over time due to a change in the amount of resources or a change in neighboring populations. If the number of resources exceeds the number of organisms or an opposing population is at a decline, the population will grow. Once the population has surpassed the spare resources, it will stabilize. Eventually the population will decline when resources have become more limited or the opposing population is stronger. There are many other factors that may determine deterioration in population count such as human impact, pollution, and new species. Examples: number of gumballs in a gumball machine, number of people in the United States, and number of socks in a dryer.

Monocot and Dicot



A monocot, or monocotyledon, is a flowering plant with one seed leave. This characteristic forms the foundation of many other characteristics: the flower parts of a monocot grow in multiples of three, its veins extend in a parallel direction up and down the leaves, it has a single-pollen structure, and its vascular system is unorganized and does not have a cortex or stele. Examples: bananas, wheat, corn, rice, ginger, onions, sugarcane, lilies, and daffodils.

A dicot, or dicotyledon, is a flowering plant with two seed leaves. Like the monocot, the number of seed leaves also determines many of its other characteristics: its flower parts grow in multiples of four or five, the veins of its leaves are reticulated, it has a three-pollen structure, and its vascular system contains a cortex and stele and is arranged in rings. Examples: peas, beans, peanuts, mint, and grass.

Epithelial Tissue

Epithelial tissue is more commonly called skin.

Epithelial tissue is the outer covering of the surface of the body. It can either be described as simple epithelium, meaning its layers are one cell thick, or stratified epithelium, where its layers are two or more cells thick. Each division is subdivided into three subdivisions determined by the shape of the cells: squamous, cuboidal, and columnar. Squamous cells have a flat, thin shape and are found lining the surfaces of certain organs. Cuboidal cells have a cube-like shape and are found on absorptive organs and glands. Columnar cells look like vertically lengthened cuboidal cells and are usually specialized as sensory receptors. A unique classification of simple epithelium is pseudostratified, where the location of the nuclei of simple columnar cells are irregular, so they appear to be stratified. The functions of epithelial tissue are sensation, protection of core tissue from damage, secretion of substances, absorption of nutrients and moisture, excretion of wastes, and the diffusion of gases.

Artificial Selection

This dog is a miniature schnauzer. It's an example of artificial selection because it was specifically bred apart from the standard schnauzer for its smaller size.

Artificial selection is the intentional breeding of traits. The term “artificial selection” was first used by naturalist Charles Darwin, to distinguish the process from natural selection, in which organisms develop naturally to adapt to a particular environment. This artificial selection is practiced to encourage human influence in the development of plants and animals and to acquire a desired characteristic or function. The conflict that arises with this form of breeding is the susceptibility to disease or environmental changes and the extinction of the stronger natural species. Examples: livestock bred to increase meat production, thouroughbred animals, flowers bred for a specific color.

Homologous Structures

A dog's paw and a human's hand have similar bone structure.

Homologous structures are anatomical similarities shared between species that indicate a common ancestor. Some homologous structures are not functional or are naturally lost throughout development. Homology is the opposite of analogy, where although the structures or abilities of the organisms are similar, they have evolved separately from their common ancestors to a point where they are unrelated. Examples: humans, dogs, birds, and whales all have similar skeletal structure of the forelimbs.