Big idea: A niche is like a species’ job description — it explains how a species survives, not just where it lives.
Niche and habitat (very important!)
These two terms are often mixed up, but they mean different things.
- Habitat = its address (where it lives)
- Niche = its job (how it lives)
- Many species can share the same habitat (like many people in one city)
- But each species has its own niche (like everyone has a different job)
Habitat = address. Niche = job.
What does a niche include?
A niche includes all the ways a species uses its environment.
- Type of food eaten (e.g. owls eat mice, bees eat nectar)
- How food is obtained (e.g. hunting, grazing, filtering)
- Time of activity (e.g. night or day)
- Interactions with other species (e.g. predator, pollinator, decomposer)
- Tolerance to abiotic factors (e.g. temperature, water, light)
Example: A woodpecker’s niche: lives in forests, eats insects in tree bark, makes holes for nests, active during the day.
In exams, describe a niche using feeding role + interactions + conditions needed.
Resource use
Species survive by using resources from their environment.
- Resources
- Different species use different resources (e.g. some birds eat seeds, others eat insects)
- Using different resources reduces competition
Different niches = less competition.
Niche overlap and competition
When species use the same resources, their niches may overlap.
- Niche overlap
- Leads to competition
- Competition can reduce population size
- One species may become less successful (or even disappear)
Example: If two types of birds eat the same seeds, they compete. If one switches to eating insects, both can survive.
Too much niche overlap = more competition.
Why niches matter in ecosystems
Niches help explain how many species can live together in the same ecosystem.
- Different niches allow species to coexist (like different jobs in a city)
- More niches usually mean higher biodiversity
- If a niche disappears, ecosystem balance can be disturbed