Parasitism is a type of biological relationship where one organism benefits while the other is harmed.
🦠 Definition
Parasitism is a relationship between two organisms in which:
- The parasite benefits (+)
- The host is harmed (−)
This is often written as: (+ / −)
🧬 How it works
A parasite:
- Lives on or inside a host
- Gets food, shelter, or nutrients from the host
- Usually does not kill the host immediately (because it needs it to survive)
🐛 Examples
🧍♂️ Humans & parasites
- Tapeworms in the intestines
- Lice on the scalp
- Malaria parasite (Plasmodium) in blood cells
🐜 Animals & plants
- Ticks feeding on dogs or cattle
- Mistletoe plant drawing nutrients from trees
- Fleas on mammals
⚖️ Types of parasites
- Ectoparasites: live on the outside (lice, ticks)
- Endoparasites: live inside the body (tapeworms, protozoa)
- Obligate parasites: must live in a host to survive
- Facultative parasites: can live independently but may parasitize
🌿 Why it matters
Parasitism affects:
- Human health (diseases)
- Agriculture (crop damage)
- Animal survival
- Ecosystem balance
🧠 Simple way to remember
Parasite = benefits
Host = pays the price
If you want, I can also compare parasitism with mutualism and commensalism—they’re often tested together in biology.
