7th grade · Science · Unit 2 of 10
Ecosystems
Living and non-living parts
What your child practices
Biotic and abiotic parts of an ecosystem, how they interact, and the limiting factors and carrying capacity that decide how many organisms an ecosystem can support.
Maine Learning Results learning standard: MS-LS2-1; MS-LS2-2 · how resources limit populations and how organisms interact in ecosystems
How we explain it
Children can open this short lesson before they practice.
- An ecosystem is living things (biotic) and their non-living surroundings (abiotic) interacting.
- Abiotic parts include water, light, soil and temperature.
- A limiting factor, such as food or space, caps how many organisms an area can support: its carrying capacity.
Example: Is sunlight a biotic or an abiotic part of a pond ecosystem? Biotic means living or once living. Sunlight is not alive. Answer: abiotic
Ecosystems in Maine
In the Maine Learning Results, this is unit 2 of 10 in 7th grade Science, after Atoms & Elements and before Food Chains & Energy.
Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.
Source: Maine Department of Education
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What is an ecosystem?
- All the carnivores in a region
- A network of interactions among living things and their non-living surroundings
- Only the plants that grow in one place
- A group of animals of the same species
A network of interactions among living things and their non-living surroundings
Hint: An ecosystem includes both the living (biotic) and non-living (abiotic) parts, and the ways they affect each other.
Question 2
Biotic or abiotic? Sort each part of an ecosystem.
Sort into: 🌱 biotic (living) · 🪨 abiotic (non-living)
- 🦠bacteria in the soil
- 💧water in a stream
- 🌬️wind
- 🍄a mushroom
- ☀️sunlight
- 🌡️the temperature
- 🐸a frog
- 🌳a maple tree
🌱 biotic (living): bacteria in the soil, a mushroom, a frog, a maple tree · 🪨 abiotic (non-living): water in a stream, wind, sunlight, the temperature
Hint: Biotic parts are living things (plants, animals, fungi, bacteria). Abiotic parts are the non-living things, such as sunlight, water, air, rock and temperature.
Question 3
Which of these is an abiotic component of a forest ecosystem?
- moss on a log
- the amount of sunlight
- a woodpecker
- bacteria in the soil
the amount of sunlight
Hint: Abiotic means non-living. Light, water, air, soil minerals and temperature are abiotic.
Question 4
Why can a small pond support fewer fish than a large lake?
- Ponds have no producers
- It has less space, food and dissolved oxygen
- Fish need less food in ponds
- Pond fish are always larger
It has less space, food and dissolved oxygen
Hint: A bigger ecosystem has more of the resources that limit a population.
Question 5
Which abiotic factor most limits plant growth in a desert?
- the lack of water
- strong ocean tides
- too much shade
- deep snow
the lack of water
Hint: Plants need water. Deserts get very little rain.
Question 6
Lake water warms during a heat wave and holds less dissolved oxygen. How might this affect fish?
- Fish are not affected at all
- Fish that need a lot of oxygen may struggle to survive
- All fish grow faster
- Fish breathe more easily
Fish that need a lot of oxygen may struggle to survive
Hint: Warm water holds less dissolved oxygen, an abiotic factor that fish need.