TROPHIC CHAIN
Every living thing needs to do its vital functions (reproduction, relationship and nutrition). Everytime animals do something (run, jump) they use energy to do so.
Animals get energy from the food they eat, and all living things get energy from food. Plants use sunlight, water and nutrients to get energy (in a process called photosynthesis). Energy is necessary for living beings to grow.
The trophic chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature, how all the living things are connected by the way to get the energy that we need. Trophic chain starts with plant-life, and end with animal-life. Some animals eat plants, some animals eat other animals.
An example of a simple trophic chain (or food chain) could be: start with grass, which is eaten by rabbits and then the rabbits are eaten by foxes.
BIOACCUMULATION
Bioaccumulation is defined as the accumulation of chemicals in the tissue of organisms through any route, including respiration, ingestion, or direct contact with contaminated water, sediment, and pore water in the sediment.
The onbly substances that are bioaccumulated are the ones that aren’t digested, usually are accumulated in fats.
As the level on the trophic chain increase, the level of bioaccumulation increase too. If a big organism consumes many of the small organisms, the dose (or concentration) of the substances becomes larger than it was in the smaller organisms. This process is called biomagnification, and it takes place when organisms higher in the food chain eat many of the smaller organisms that have bioaccumulated the chemical from the environment.
By: Paula Martínez Misa
4ESO-2013/14 