Environmental Growth Factors - Middle School Life Science

Identify the limiting factor: fish die in a warm pond because dissolved $O_2$ becomes low.

Oxygen availability. Warm water holds less dissolved oxygen than cold water.
What term describes the maximum population size an environment can support long term?

Carrying capacity. Limited by resource availability and environmental conditions.
Identify the limiting factor: crops turn yellow and grow poorly in soil lacking nitrate ions.

Nitrogen deficiency (low nutrients). Nitrogen is essential for making proteins and chlorophyll.
Which abiotic factor describes how acidic or basic soil or water is, affecting nutrient uptake?

pH. Extreme pH can denature proteins and affect nutrient solubility.
Which biotic factor can decrease growth by causing illness and using host resources?

Disease (pathogens). Parasites and infections divert energy from growth to immune response.
What is the biotic factor called when pathogens cause disease that reduces growth or survival?

Disease (parasitism/pathogens). Pathogens weaken hosts, reducing growth and reproduction.
Identify the limiting factor: a plant grows slowly because nitrate levels in soil are low.

Nutrient availability (nitrogen). Nitrogen is essential for proteins; low N limits plant growth.
Which abiotic factor can slow growth by removing water from organisms and damaging tissues?

High salinity. Causes dehydration and disrupts cellular osmotic balance.
Which environmental factor can limit growth when organisms are crowded and resources run out?

Population density (crowding). Too many organisms deplete resources faster than they regenerate.
Identify the limiting factor: a cactus grows poorly when soil salinity becomes very high.

Salinity (salt concentration). High salt disrupts water uptake and cellular processes.
Which biotic factor can reduce prey growth by increasing death rate and stress?

Predation pressure. Constant threat forces prey to spend energy on defense instead of growth.
Which abiotic factor describes the amount of available living space for a population to grow?

Space (habitat area). Limited space restricts population growth and resource access.
What environmental factor is required for photosynthesis and can limit plant growth when scarce?

Carbon dioxide (CO $_2$ ). Raw material plants convert into glucose during photosynthesis.
Identify the limiting factor: seedlings wilt and stop growing during a long period with no rain.

Water availability (drought). Plants need water for photosynthesis and maintaining cell pressure.
Which abiotic factor describes the concentration of salts in water that can affect growth?

Salinity. High salt levels can dehydrate cells through osmosis.
Which abiotic factor is the amount of $O_2$ available for cellular respiration and growth?

Oxygen availability. Most organisms need oxygen to release energy from food.
Identify the limiting factor: a plant grows slowly because it receives only 2 hours of sunlight daily.

Light availability. Insufficient light limits photosynthesis and energy production.
Which environmental factor describes the supply of minerals such as nitrogen and phosphorus for growth?

Nutrient availability. Essential elements needed to build proteins, DNA, and other molecules.
Which abiotic factor includes soil texture and drainage that influence root growth?

Soil properties (texture, structure, and drainage). Soil type affects water retention and root penetration.
What is the term for living things in an environment that affect growth?

Biotic factors. Living organisms like predators, prey, and competitors affect growth.
Which abiotic factor directly supplies energy for photosynthesis and plant growth?

Light (sunlight intensity and duration). Plants convert light energy into chemical energy through photosynthesis.
What environmental factor is required for cellular respiration and can limit animal growth when low?

Oxygen availability (O $_2$ ). Essential for breaking down glucose to release energy in cells.
Which type of environmental factor includes temperature, light, water, and soil pH?

Abiotic factors. Nonliving physical and chemical factors that affect organisms.
Which biotic interaction reduces growth because organisms use the same limited resources?

Competition. Organisms compete for food, water, space, and other necessities.
Which term describes the maximum population size an environment can support long term?

Carrying capacity. Limited by resources like food, water, and space.
Which abiotic factor is the amount of $CO_2$ available that can limit photosynthesis?

Carbon dioxide availability. Plants need $CO_2$ as a raw material for photosynthesis.
What is the term for nonliving conditions that affect organism growth?

Abiotic factors. Nonliving conditions like temperature, water, and light affect organisms.
Which abiotic factor is most directly needed for plant cells to maintain turgor and grow?

Water availability. Plants need water for photosynthesis, transport, and cell expansion.
What soil property affects nutrient availability and can slow growth when too acidic or basic?

pH. Extreme pH values can denature enzymes and lock up nutrients.
Which environmental factor affects growth by controlling hydration and transport of materials in cells?

Water availability. Essential for all life processes and maintaining cell structure.
What term describes all living and nonliving surroundings that influence an organism's growth?

Environment. Includes both living (biotic) and nonliving (abiotic) components.
Which type of environmental factor includes predators, competitors, and pathogens?

Biotic factors. Living organisms that interact with and affect other organisms.
Which abiotic factor most directly affects enzyme activity and growth rate in organisms?

Temperature. Enzymes work best at optimal temperatures; extremes slow or stop growth.
Which environmental factor provides the energy source that limits plant growth in many habitats?

Light availability (sunlight). Primary energy source for photosynthesis and food production.
Which abiotic factor refers to dissolved mineral nutrients needed for plant growth?

Nutrient availability (for example, nitrogen and phosphorus). Plants need minerals like N and P to build proteins and DNA.
What environmental factor most directly affects enzyme activity and metabolic rate in organisms?

Temperature. Controls chemical reaction rates and protein function in cells.
What is the biotic interaction called when one organism eats another, affecting population growth?

Predation. Predators control prey populations and affect ecosystem balance.
What is the biotic interaction called when organisms compete for the same limited resource?

Competition. Organisms compete for food, water, space, and mates.
Identify the limiting factor: fish in a pond gasp at the surface after algae die off and decay.

Low dissolved oxygen. Decomposing algae consume oxygen, causing fish to suffocate.

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