7th grade · Science · Unit 3 of 14
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.
New York State Learning Standards 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 New York
In the New York State Learning Standards, this is unit 3 of 14 in 7th grade Science, after Circuits & Static 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.
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
An invasive plant crowds out native plants. Why does this change the ecosystem?
- Invasive plants never compete with others
- Native plants lose light, space and nutrients, and the animals that eat them may be affected
- The abiotic parts of the ecosystem disappear
- Native plants gain more sunlight
Native plants lose light, space and nutrients, and the animals that eat them may be affected
Hint: Invasive species compete with native ones for the same limited resources.
Question 2
Biotic or abiotic? Sort each part of an ecosystem.
Sort into: 🌱 biotic (living) · 🪨 abiotic (non-living)
- 🌬️wind
- 🦠bacteria in the soil
- 🌳a maple tree
- 🪨a boulder
- 🦫a beaver
- ☀️sunlight
- 🌡️the temperature
- 🐸a frog
🌱 biotic (living): bacteria in the soil, a maple tree, a beaver, a frog · 🪨 abiotic (non-living): wind, a boulder, 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 is the best example of a limiting factor that is not about food?
- a long, warm summer with plenty of rain
- an increase in plant growth
- more insects hatching in spring
- a shortage of nesting sites for cavity-nesting birds
a shortage of nesting sites for cavity-nesting birds
Hint: Space and shelter limit populations as well as food.
Question 4
Which is a biotic limiting factor for a population of rabbits?
- the amount of rainfall
- predators such as foxes
- the air temperature
- the hours of daylight
predators such as foxes
Hint: Biotic limiting factors are living things, such as predators, disease and competitors.
Question 5
A disease kills many trees in a forest. What is a likely effect?
- Animals that depend on those trees lose food or shelter
- Nothing else in the ecosystem changes
- More sunlight stops reaching the forest floor
- Only abiotic factors are affected
Animals that depend on those trees lose food or shelter
Hint: Trees are producers and also give shelter. Losing them affects the animals that use them.
Question 6
A beaver builds a dam and floods a meadow. What does this show?
- Energy is created by animals
- Only abiotic factors can change an ecosystem
- Producers have eaten the consumers
- A living thing can change the non-living parts of its ecosystem
A living thing can change the non-living parts of its ecosystem
Hint: The beaver (biotic) changed the water level and land (abiotic).