Grade 8: Lesson 4.4 Bioaccumulation

A process where a substance, like a pesticide, accumulates in an organism over time.

Organisms that break down dead plants and animals into simpler substances.

Substances that decomposers cannot break down, often persisting in the environment for a long time.

A pesticide that was widely used to control insects, but its harmful effects on other organisms led to its ban.

The buildup of a substance in an organism's body over its lifetime.

The increasing concentration of a substance as you move up the food chain.

The harmful effects of pollution on an ecosystem.

Types of pollution and their effects on ecosystems.

Organisms that break down dead plants and animals into simpler substances.

Decomposers can break down organic matter like dead leaves, animal waste, and wood.

Decomposers cannot break down synthetic materials like plastics, metals, and some pesticides.

Pollution can disrupt the balance of an ecosystem, harming its inhabitants and impacting food webs.

Types of pollution include air pollution, water pollution, and soil pollution, each affecting ecosystems in different ways.

Pesticides are chemicals designed to kill insects, but some can persist in the environment and harm other organisms.

Bioaccumulation is the gradual buildup of substances, such as pesticides, in an organism's body over time.

An organism absorbs a substance faster than it can be eliminated, leading to a gradual increase in its concentration in the body.

DDT (dichlorodiphenyltrichloroethane) is a pesticide that was widely used to control insects, especially mosquitoes.

DDT was used to control mosquito-borne diseases like malaria and flea-borne diseases like typhus.

DDT was also used to kill insects that damage crops, protecting agricultural yields.

DDT's persistence in the environment and its ability to harm non-target organisms were not initially understood.

DDT's impact on animals other than insects, like birds and fish, raised concerns about its environmental effects.

DDT is considered a persistent chemical, meaning it remains in the environment for a long time.

Decomposers cannot break down DDT effectively, so it stays in the environment for many years.

When DDT is sprayed, it can be carried long distances by wind currents, spreading its presence beyond the intended area.

DDT accumulates in the body of organisms and is not easily broken down or eliminated.

DDT is toxic, meaning it is poisonous and can harm animals, even in small doses.

DDT can make bird eggshells thin and fragile, increasing the risk of breakage and hindering reproduction.

An example of DDT's impact: the eggs of an ibis bird did not hatch, likely due to DDT accumulation in the mother.

When DDT enters an aquatic ecosystem, it can be taken up by algae, which are then eaten by shrimps, then fish, and so on.

As DDT moves up the food chain, its concentration increases in each organism because it's accumulated from the food they eat.

Biomagnification is the process of increasing DDT concentration in organisms as you go higher up the food chain.

Bioaccumulation refers to the buildup of a substance in a single organism over its lifetime, while biomagnification refers to the increasing concentration of that substance as you move up the food chain.

The concentration of DDT in a cormorant (top predator) is significantly higher than in a minnow (lower in the food chain).