Study Guide

Quick meanings for every word. Pair Tier 3 words with pictures to support newcomers.

Word	Meaning
Energy	The ability to cause change or do work.
Biomass	The total mass of living or once-living material in an area, which stores the energy captured by producers.
Bromothymol Blue Solution	An acid–base indicator that changes from yellow in acidic conditions toward blue in basic conditions. Dissolving carbon dioxide can lower the pH.
Chlorophyll	A green pigment that absorbs light used in photosynthesis.
Chloroplasts	An organelle in plant and algal cells where light energy is used to make sugars.
Guard Cells	Pairs of cells that open and close small pores in a leaf, controlling how gases like carbon dioxide and oxygen move in and out.
Indicator	A substance or observation that signals a condition or change; an acid–base indicator changes color over a particular pH range.
Mitochondria	Organelles that release energy from food for the cell to use.
Photosynthesis	A process in which plants, algae, and some bacteria use light energy to make sugars from carbon dioxide and water, releasing oxygen.
Cellular Respiration	Processes that release usable energy from food molecules; the oxygen-using form produces carbon dioxide and water.
Sustainability	Using resources in a way that meets today’s needs without using them up for the future.
Stomata	Small pores in leaves and some stems that allow gas exchange; guard cells regulate their openings.
Yeast	A single-celled fungus that breaks down sugar and releases carbon dioxide gas as a byproduct.
Abiotic	Related to the nonliving parts or conditions of an environment.
Aquatic	Living in or related to water, such as a lake, river, or ocean environment.
Biome	A large region with a certain climate and the plants and animals that live there.
Biotic	Related to living things in an environment.
Carrying Capacity	The largest population an environment can support over time.
Climate	The usual weather of a place over many years.
Ecosystem	All the living and nonliving things in an area and how they interact.
Habitat	The place where an organism lives and finds what it needs.
Limiting Factor	Anything that keeps a population from growing larger, like food, water, or space.
Organism	Any living thing.
Precipitation	Water that falls from clouds as rain, snow, sleet, or hail.
Radiation	Transfer of energy by electromagnetic waves, which can travel through empty space.
Resource	Anything an organism needs and uses from its environment, such as food, water, or shelter.
Taiga	A cold biome with long winters and forests of cone-bearing trees.
Temperate Forest	A biome with four seasons and trees that often lose their leaves in fall.
Tundra	A cold, mostly treeless biome with a short growing season; many areas have permanently frozen ground below the surface.
Topography	The shape of the land’s surface, including its hills, valleys, and slopes.
Tropical Forest	A forest in the tropics; rainfall patterns distinguish wet forests from seasonally dry forests.