Interdependence of Living Systems Parts of this Powerpoint are highlighted or in a different color font to assist dyslexic students.

Vocabulary Homeostasis – process used by the body internally to stay stable externally Negative feedback – a way to stay stable using a process that is turned off by the condition it produced

Hormone – chemical produced by endocrine gland that affects the activity of a tissue or organ Diffusion – process that allows substances to move back and forth through a cell membrane

Osmosis – the diffusion of water molecules through a selectively permeable membrane Turgor pressure – pressure of water against the cell wall of plant cell

The Body must stay in equilibrium Homeostasis is the process by which the body keeps all systems working properly. Must combat external forces to maintain equilibrium. Negative feedback systems keep equilibrium. Example: sweating and shivering

Example 1 Energy used by the body comes from breakdown of glucose through a chemical reaction The level of glucose is controlled by hormones in the endocrine system One hormone is insulin

Example 2 Homeostasis requires the amount of water in a system to be regulated Cells (plant and animal) have a membrane that allows substances to move back and forth This is called diffusion – in which a high concentration of molecules moves into an area where the concentration is lower

Turgor Pressure Plant cell walls allow for expansion As water moves in the cell membrane expands against the cell wall The pressure is called turgor pressure and is what helps give the plant shape and firmness

Interactions Among Living Things http://www.realtrees4kids.org/sixeight/home.htm

Niche Each organism has unique characteristics that allow it to serve a specific purpose in the ecosystem – that is its niche This niche includes how the organism interacts with other organisms There are 3 major types of interactions: competition predation symbiosis

Competition Different species can share same food needs but not the same niche If they do occupy the same niche one of them will die off Ecosystem has a limited amount of food, water, and shelter the struggle to survive in a particular habitat is competition www.champaignschools.org

Predation The hunting and killing of another animal for food is predation The organism doing the killing is the predator while the animal being killed is the prey Many animals have developed some type of adaptation to help it catch and kill prey Others have developed adaptations to avoid being caught Predation has a major effect on the size of a population A population size grows and reduces depending on food availability & disease

Symbiosis There are 3 types of symbiotic relationships between organisms These are : mutualism commensalism parasitism

Mutualism This is relationship in which both species benefit is mutualism Commensalism A relationship in which one species benefits and the other one is neither helped nor harmed

Parasitism This relationship is one in which one organism lives on or inside another organism and harms it The one that benefits is called a parasite and the host is the one that is harmed Teacher Note-There is a parasite that lays its eggs in a human when they are bitten by a mosquito in Africa. When the parasite goes to reproduce it travels down to the legs and feet. There the animal lays its eggs. When they hatch the worm bores a hole through the skin. A doctor uses thread to wind the worm around the thread as he/she draws out the worm.