Total Pageviews

Friday, February 4, 2011

introduction

What is ecology?

Ecology is the scientific study of interactions of organisms with one another and with the physical and chemical environment. Although it includes the study of environmental problems such as pollution, the science of ecology mainly involves research on the natural world from many viewpoints, using many techniques. Modern ecology relies heavily on experiments, both in laboratory and in field settings. These techniques have proved useful in testing ecological theories, and in arriving at practical decisions concerning the management of natural resources.

An understanding of ecology is essential for the survival of the human species. Our populations are increasing rapidly, all around the world, and we are in grave danger of outstripping the earth’s ability to supply the resources that we need for our long-term survival. Furthermore, social, economic and political factors often influence the short-term distribution of resources needed by a specific human population. An understanding of ecological principles can help us understand the global and regional consequences of competition among humans for the scarce natural resources that support us.Thus, it is a science that contributes considerably to our understanding of evolution, including our own evolution as a species

introduction video



to view in full HD
(recommended)

cell


Definition
noun
(Science: Cell Biology)
1. The structural, functional and biological unit of all organisms.
2. An autonomous self-replicating unit that may exist as functional independent unit of life (as in the case ofunicellular organism), or as sub-unit in a multicellular organism (such as in plants and animals) that is specialized into carrying out particular functions towards the cause of the organism as a whole.
3. A membrane bound structure containing biomolecules, such as nucleic acidsproteins, andpolysaccharides.

Supplement
There are two distinct types of cellsprokaryotic cells (e.g. bacterial cells) and eukaryotic cells (e.g. plant or animal cell). The main difference between the two is a well-defined nucleus surrounded by a membranous nuclear envelope present only in eukaryotic cells. Despite this difference they share a number of common features: the genetic information is stored in genesproteins serve as their main structural material, ribosomes are used to synthesize proteins, adenosine triphosphate is the main source of metabolic energy to sustain various cellular processes, and a cell membrane that controls the flow of substances into and out of the cell.

Word origin: From Latin cella

tissue


Definition
noun, plural: tissues
An aggregate of cells in an organism that have similar structure and function.

Supplement
The fundamental types of tissues in animals are epithelialnerveconnectivemuscle, and vascular tissues whereas in plants, they are the meristematic (apical meristem and cambium), protective (epidermis andcork), fundamental (parenchymacollenchyma and sclerenchyma) and vascular (xylem and phloem) tissues. Tissues that work in unison to carry out a specific set of functions form an organ.

Word origin: Middle English tissu, a rich kind of cloth, from Old French, from past participle of tistre, to weave, from Latin texere.

organ


Definition
noun, plural: organs
A group of tissues that perform a specific function or group of functions.

Supplement
Examples of animal organs are heartlungsbraineyestomachspleenbonespancreaskidneysliver,intestinesskinurinary bladder and sex organs.
Examples of plant organs are the rootsstemsleavesflowersseeds and fruits.

Word origin: L. Organum, Gr.; akin to work, and E. Work: cf. F. Organe.