Populations, communities & ecosystems
Practice Flashcards
Flip to reveal answersDefine a population.
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 14 Flashcards — Populations, communities & ecosystems
Sign up free to track progress and get spaced-repetition review schedules.
Question
Define a population.
Answer
All the individuals of the **same species** living in the **same area at the same time**.
Question
Define a community.
Answer
All the populations of **different species** living together and **interacting** in the same area.
Question
Define a habitat.
Answer
The **place** (the type of environment) where a species or community normally lives.
Question
Define an ecosystem.
Answer
A **community** of organisms together with the **abiotic (non-living) environment** it interacts with.
Question
Define species richness.
Answer
The **number of different species** present in a community (a simple count, ignoring how many of each).
Question
What is the nesting order of the ecological levels?
Answer
**Population → community → ecosystem** — one species, then many populations, then community plus its environment.
Question
What is the key difference between a community and an ecosystem?
Answer
A community is the **living organisms only**; an ecosystem **also includes the abiotic (non-living) environment**.
Question
How are the individuals in a community related?
Answer
Their populations **interact and depend on one another** — through feeding relationships, competition and other interactions.
Question
What two basic types of organism make up a community?
Answer
**Autotrophs (producers)** that make their own food, and **heterotrophs (consumers and decomposers)** that take in food made by others.
Question
What is an autotroph?
Answer
An organism that **makes its own food**, usually by **photosynthesis** (a producer, e.g. grass or algae).
Question
What is a heterotroph?
Answer
An organism that **takes in food made by other organisms** (a consumer or decomposer, e.g. a rabbit, fox or fungus).
Question
On a diagram, what does an oval enclosing autotrophs, heterotrophs AND the abiotic environment represent?
Answer
An **ecosystem** — because it includes the non-living environment as well as the living organisms.
Question
Does a community include abiotic (non-living) factors?
Answer
**No** — a community is living organisms only. Adding the abiotic environment makes it an **ecosystem**.
Question
How is species richness different from abundance?
Answer
**Species richness** counts how many **different species** there are; **abundance** counts how many **individuals** of a species there are.
Read the notes
Full study notes for Populations, communities & ecosystems
Topic 3.8 hub
Populations and communities
More from Topic 3.8
All flashcards in this topic
Biology exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free