Biology

Tuesday, February 21, 2012

Biological control of pests simply means an introduction of a species that could terminate the pests
Advantages of Biological control is no toxic chemical and less impact on the wild life
Disadvantages to biological control is that it is not 100% effective, it is difficult to control and it is difficult to match the predator to the prey. Also new pests may be created in the process of trying to get rid of the original pest eg. cane toads

Large fields of crops of the same type = monoculture
Monocultures attract a lot of pests, this reduces prodcutivity (food and finacial gain)
To reduce the amount of pests, farmers use pesticides which are chemicals that kills the pest
Advantages to pesticides is that it is easy to obtain, apply and are very effective
Disadvantages to pesticides is that they are toxic and are harmful to humans and animals

Fertilizers take the form of nitrates and phosphates
Fertilizers are taken up the root by active transport and dissolved in water which is taken to the leaf by the xylem
Nitrates are involved with protein and Phosphates are involved with DNA and membrain strcuture
There are 2 types of fertilizers (artificial and organic)
Artificial takes the form of Potassium Nitrate and Ammonium nitrate
Organic takes the form of animal waste (most of the time cow waste)

Increasing in temperature will also increase the rate of reaction of enzymes of the plant
Increased concentration in CO2 is substrate
Increasing the temperature and the carbon dioxide level will result in an increase in the rate of photosynthesis
An increased rate in photosynthesis means that the plants will produce a higher yield
Formula for photosynthesis is carbon dioxide + water = oxygen + glucose

Glass houses are made of glass to let as much sunlight in as possible
Solar radiation is the source of energy (from light)
Light goes through the glass and is absorbed by the surface inside the glass house (soil, plants etc.)
Plants re-emit the heat thus causing warm air and causing increase in temperature
High temperature enables plants to increase yields to certain crops.
Such as constant temp. per year, prevention of frost damage and prevention of loss of water vapor

Hyperthalamis is a region of the brain which responds to the stimuli (temperature of blood)
Temperature is the stimuli, hyperthlamis is the receptor, skin activity is the responce
If temperature is too warm, the response of the skin would be sweating, vasoliation and hairs flat
If temperature is too cold, the response of the skin would be shivering, hair raised and vasoconstriction
Homeothermic carries out a process called Thermoregulation.
Mammals body temperature is 37 to 38 degrees celcius

Sensitivity is the characteristic of the organisms respond to changes in their environment.
Changes in the environment is also known as the stimuli which include: Light, temperature, pressure and chemical.
Organisms are required to have receptors and effectors such as muscles and glands, to detect the stimuli
Response is used to adapt to the stimuli to survive the changes in the environment.
The "s" in mrs. gren stands for sensitivity
http://www.youtube.com/watch?v=U9faLNDFSNY