⁣Interdependence. All organisms in an ecosystem depend upon each other. If the population of one organism rises or falls, then this can affect the rest of the ecosystem. If the foxes in the food chain above were killed, the population of rabbits would increase because they are no longer prey to the foxes.

⁣Most gas exchange surfaces are extremely thin (sometimes just one cell thick), ensuring a short diffusion pathway across the exchange surface. They will also have a large surface area to volume ratio which provides more space for the diffusion of gases.

⁣“Global warming” refers to the rise in global temperatures due mainly to the increasing concentrations of greenhouse gases in the atmosphere. “Climate change” refers to the increasing changes in the measures of climate over a long period of time – including precipitation, temperature, and wind patterns.

⁣At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide. Your bloodstream then carries this waste gas back to the lungs where it is removed from the bloodstream and then exhaled. Your lungs and respiratory system automatically perform this vital process, called gas exchange.

⁣This allows the nutrients from these foods to be easily absorbed into your blood and carried through your body. There are several digestive enzymes, including amylase, maltase, lactase, lipase, sucrase, and proteases.

⁣Methods of contraception include oral contraceptive pills, implants, injectables, patches, vaginal rings, Intra uterine devices, condoms, male and female sterilization, lactational amenorrhea methods, withdrawal and fertility awareness based methods.

Biolab is a short educational DVD aimed at GCSE Biology students in the UK. We learn about one of the three main types of pathogen, the virus, and the immune system's response to it.<br />
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The DVD formed part of my final year project for my degree in digital animation at the University of Greenwich, and it features particle systems and small-scale crowd simulations to depict the behaviour of cells and virus particles. It was created in 3ds Max and rendered with mental ray.<br />
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The music was produced by David Utton and the voiceover was provided by Michele Walford.

⁣Plant cells have a cell wall in addition to a cell membrane, whereas animal cells have only a cell membrane. Plants use cell walls to provide structure to the plant. Plant cells contain organelles called chloroplasts, while animal cells do not.

⁣Specialised cells are cells designed to carry out a particular role in the body, such as red blood cells which are designed to carry oxygen. Nerve cells help contraction of muscles or the relaxation of muscles according to what specific job you need them to do.

⁣Specialised animal cells have components that allow them to complete a specific purpose. Specialised animal cells include red blood cells, sperm, eggs, nerve cells, muscle cells, ciliated cells, and villi.

⁣Each leaf typically has a leaf blade ( lamina ), stipules, a midrib, and a margin. Some leaves have a petiole, which attaches the leaf to the stem; leaves that do not have petioles are directly attached to the plant stem and are called sessile leaves.

A cell ⁣ ⁣the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body. A cell has three main parts: the cell membrane, the nucleus, and the cytoplasm. The cell membrane surrounds the cell and controls the substances that go into and out of the cell.⁣

⁣“Active Transport is defined as a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy.”

⁣Biotic factors are living things within an ecosystem; such as plants, animals, and bacteria, while abiotic are non-living components; such as water, soil and atmosphere. The way these components interact is critical in an ecosystem.

⁣The functioning of the water cycle involves a change in energy which leads to a difference in temperature. The carbon cycle is a biogeochemical cycle that facilitates the exchange of carbon through the different compartments of earth. Carbon is the backbone of all biological compounds and many minerals like limestone. ⁣The terrestrial carbon and water cycles are strongly coupled. As atmospheric carbon dioxide concentration increases, climate and the coupled hydrologic cycle are modified, thus altering the terrestrial water cycle and the availability of soil moisture necessary for plants' carbon dioxide uptake.

⁣In sexual reproduction, an organism combines the genetic information from each of its parents and is genetically unique. In asexual reproduction, one parent copies itself to form a genetically identical offspring.

⁣Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar.

⁣Meiosis is a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes (the sex cells, or egg and sperm). In humans, body (or somatic) cells are diploid, containing two sets of chromosomes (one from each parent).

⁣There are different tests which can be used to detect carbohydrates, proteins and lipids.
They involve adding a reagent to a food sample which changes colour depending on what biological molecules are present.

⁣Health, as defined by the World Health Organisation, is a state of mental, social as well as physical being. Disease being the opposite, is a hindrance in the well being of our body that affects the functioning of organs and organ systems.