Ecosystems and Flow of Energy Study Guide
TEKS 5.9A Ecosystems
Be able to observe the way organisms live and survive in their ecosystem by interacting with
the living and non-living elements.
 Environment - All of the living and nonliving things that surround and affect an organism
o Abiotic Factors– Non-living elements in an environment (ex. air, water, soil,
climate, nutrients)
o Biotic Factors – Living elements in an environment (ex. plants & animals)
 Ecosystem – A community of interacting organisms and their physical environment
 Community - All of the populations that live and interact in an area
 Population – A group of organisms of the same species in a community
 Habitat- The place where an organism naturally lives and grows.
 Niche - Where an organism’s specific location is; its role in the community
o Broad Niche – An organism that can eat a variety of food. They often move around
large areas.
o Narrow Niche – An organism that has a very specific way of living. These organisms
tend to live in specific places.
 Competition - Interactions between populations to meet their needs
 Diversity – The variety of different species in an ecosystem
o Limiting Factors - Factors not available for every organism: food, water, shelter, space
o The most diverse ecosystems are near the equator. The farther from the equator the
less diverse. (ex. Arctic – only polar bears and a small number of organisms can
survive the cold)
o The more diverse an ecosystem, the more resources are available.
o Factors Affecting Diversity:
 Climate (temperature and water)
 Distance from the equator
 Human interactions such as overhunting, pollution of soil and water, and
deforestation for cities and highways
 Natural Disasters
TEKS 5.9B Ecosystems
Be able to describe how the flow of energy derived from the Sun, used by producers to create
their own food, is transferred through a food chain and food web to consumers and
decomposers. Key concepts:
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All energy transferred through food chains and webs is derived from the Sun.
Producers use the Sun’s energy to create their own food through photosynthesis.
Consumers and decomposers get their energy from producers or other consumers.
The different parts of a food web are producers, consumers, and decomposers.
Herbivore – eat plants
Carnivore – eat other animals
Omnivore – eat both plants and animals
TEKS 5.9C Environmental Changes
Be able to predict the effects of changes in ecosystems caused by living organisms, including
humans, such as the overpopulation of grazers or the building of highways.
TEKS 5.9D Carbon Dioxide-Oxygen Cycle
Be able to identify the significance of the carbon dioxide-oxygen cycle to the survival of plants
and animals.
 This cycle is important because it helps keep the levels of oxygen and carbon dioxide
fairly constant in Earth’s atmosphere.
 Humans depend on oxygen released into the air by plants, and plants depend on carbon
dioxide that humans release into the air.