Few things to remember

A food web is a collection of interconnected food chains from the same ecosystem.
Arrows show the flow of energy from one organism to another.
Food webs involve multiple consumers and producers.

Plants are producers and autotrophs (synonym for producers).
They make their own food by photosynthesis (using Carbon dioxide, water, minerals and sunlight).
Plants convert light energy from the sun to chemical energy (glucose).
Note: Consumers are called heterotrophs

Secondary Consumer: Eats primary consumers for energy.
Primary Consumers: Eats plants for energy.
Producers: Make their own food by photosynthesis (using sunlight to create energy).

Decomposers are a part of the food chain but generally are not represented in a food chain.

Pyramids represent each trophic level in a food chain with horizontal bars.
The width of each bar signifies the number of organisms or the amount of biomass at that level.
The base of the pyramid represents the producers, followed by primary consumers, and so on.
Energy availability decreases as you go up the trophic levels, leading to fewer organisms at each level.
This energy loss limits the length of food chains, typically to no more than five trophic levels due to insufficient energy to support additional levels.

The pyramid of biomass illustrates the total mass of organisms at each stage of a food chain.
Producers generally have a higher biomass than primary consumers, resulting in a pyramid shape. This is a general rule and will always be produced as a pyramid shape.

The pyramid of numbers shows the relative number of organisms at each stage of a food chain.
The shape of the pyramid may vary, and it is not always pyramid-shaped. The shape depends on the number of organisms at each level.
- For example, one tree can support numerous caterpillars, altering the typical pyramid shape.
- However, food chains starting with grass will typically show a pyramid shape.

Not Pyramid Shaped (Pyramid of Numbers): Example: 1 Oak Tree → 2000 Insects → 90 Sparrows → 1 Hawk

Pyramid Shaped (Pyramid of Numbers): Grass-based food chains typically follow a pyramid shape.

Bacterial cells do not have a nucleus.
Bacteria are ubiquitous, found in air, water, on surfaces of plants, animals, rocks, and inside other living things.
They commonly have spherical (coccus), spiral (spirilla or spirochete), or rod-like (bacillus) shapes.
Bacteria reproduce primarily through fission, where one bacterium divides into two.
With sufficient warmth, moisture, and food, some bacteria can reproduce by fission approximately every 20 minutes.

Viruses are small particles consisting of a protein coat enclosing genetic material (DNA or RNA).
Examples of Viral Infections
- The common cold virus attacks cells lining the inside of the nose, causing a runny nose due to the destructive action on these cells.
- Other viral diseases include influenza, chickenpox, measles, rabies, and AIDS.

Note: Fungi is biggest, bacteria is medium sized and virus are smallest in size

Detritivores
- Eat the remains of dead plants and animals.
- Examples: Crabs, mites, earthworms, snails.
- Feed on the "garbage" of an ecosystem, including dead organisms, fallen leaves, and animal wastes.
- Eat anything that is dead, either recently or for a long time.
Decomposers
- Break down organic matter and feed on it.
- Examples: Bacteria and fungi.
- Break down dead organic matter and change it to simpler nutrients which can be recycled in the ecosystem.