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EC: Ecology Overview

It's All Connected

"When a butterfly flaps its wings in one part of the world it can cause a hurricane in another part of the world." ~ Author Unknown

The above quote references the "butterfly effect" (Edward Lorenz) that is used here as a metaphor to explain how small events can result in widespread consequences. The scope of ecology is illustrated nicely by this quote because this division of biology involves all living things and their interactions with each other and their environment. No organism acts without affecting others in its population, community, or ecosystem.

All life is tied to other life, as well as to our Earth, with common threads.

In this unit, you will investigate the dependence of all organisms on one another and the flow of energy and matter within their ecosystems. We will also look at the specific positive and negative impacts that humans have/had on our ecology.

Module Lessons Preview

In this module, we will study the following topics:

Ecology and Biomes, Energy Flow, Niche and Nutrient Cycling, Community Interactions, Populations, Environmental Issues & Human Impact

Module Key Terms

  • Ecology: the study of interactions between organisms and the nonliving components of their environment
  • Biosphere: the portion of the Earth (air, water, and land) where living things exist
  • Biotic: living things that shape and affect an ecosystem
  • Abiotic: nonliving things that shape and affect an ecosystem
  • Ecosystem: living organisms and nonliving factors of a specific area
  • Population: members of the same species living in the same area
  • Organism: the simplest level of organization in ecology, a living organism
  • Biome: an area of land with similar plants, animals, and climate
  • Habitat: a description of the physical area of a population or a community
  • Niche: the role an organism plays in the environment; including habitat
  • Photoautotrophs: organisms that use light to make their own food
  • Chemoautotrophs: organisms that get their energy from consuming inorganic molecules
  • Heterotrophs: Organisms that cannot make their own food; have to ingest food in order to get energy; also called consumer
  • Food Chain: one possible feeding relationship in an environment; arrows move in direction of energy flow
  • Herbivores: organisms that feed on producers
  • Carnivores: organisms that feed on herbivores or other consumers
  • Omnivores: organisms that eat both plants and animals
  • Decomposers: organisms that get their energy from breaking down decaying organisms without consuming them
  • Trophic Level: each step in a food chain
  • Primary Consumers: herbivores that feed directly on plants
  • Secondary Consumers: organisms that eat primary consumers
  • Tertiary Consumers: carnivores that feed on consumers or producers
  • Food Web: all possible feeding relationships in an environment
  • Biomass: the amount of dried organic material in an organism
  • Ecological Pyramids: illustrates the flow of energy, biomass, or numbers at each trophic level in an environment
  • Primary Productivity: the total amount of matter made by producers within an ecosystem
  • Water (Hydrologic) Cycle: the movement of water between different places on Earth, underground, and in the atmosphere (water cycle)
  • Evaporation: when liquid converts to gas
  • Transpiration: loss of water through stomata on leaves
  • Condensation: the transformation of gas to liquid as vapor condenses
  • Precipitation: condensation of water vapor
  • Runoff: precipitation that is not absorbed
  • Groundwater: water below the surface of the soil, between soil pores, and in rock spaces
  • Carbon Cycle: when carbon is cycled through the biotic and abiotic environment in various forms
  • Photosynthesis: the process of converting light, water, and carbon dioxide into sugar and oxygen
  • Cellular Respiration: the process of using stored energy in food, such as sugar, along with oxygen, into carbon dioxide and oxygen
  • Decomposition: the slow, breaking down of organic matter and usually assisted by microorganisms or fungi, releasing carbon dioxide into the atmosphere
  • Nitrogen Cycle: the process in which nitrogen is cycled through biotic and abiotic factors in an environment in various chemical forms
  • Nitrogen Fixation: converting nitrogen gas into ammonia by specific bacteria or lightning strikes; ammonia gets into the environment, which is a form organisms can use
  • Assimilation: consumers obtain nitrogen from the plants and animals they eat by digesting its proteins and using it to make their own proteins
  • Ammonification: decomposers return the nitrogen from the remains of dead plants and animals back to the soil as ammonia
  • Denitrification: occurs when anaerobic bacteria (chemoautotrophs) break down nitrates and release nitrogen gas back into the environment
  • Nitrification: bacteria convert ammonia into nitrates that plants can use
  • Competition: when organisms in the same or different species attempt to use an ecological resource in the same place and at the same time
  • Predation: an interaction in which one organism captures and feeds on another organism (+,-)
  • Mutualism: a symbiotic relationship in which both organisms benefit (+,+)
  • Commensalism: a symbiotic relationship in which one member benefits and the other member is unaffected (+,0)
  • Parasitism: a symbiotic relationship in which one organism benefits and the other is harmed (+,-)
  • Succession: a series of predictable changes in an environment over time
  • Sere: an intermediate community that arises through a succession
  • Primary Succession: occurs where there has never been an ecosystem
  • Secondary Succession: the repopulation of an environment after its destruction due to natural or man-made causes
  • Pioneer Species: the first species to colonize a new habitat, usually a lichen
  • Climax Community: the community that will remain stable in a given area
  • Biodiversity: the number of different species in an ecosystem and how common each species is
  • Geographic Distribution (or range): describes an area inhabited by a population
  • Population Density: the number of organisms from the same species in a given area at a specific time
  • Exponential Growth: increase in the number of organisms at a constant rate without limiting factors (J-curve)
  • Logistic Growth: realistic, slow growth curve that most populations exhibit due to limiting resources (S-curve)
  • Carrying Capacity: the maximum number of organisms an environment can support
  • Limiting Factors: conditions that limit the birth rate and/or increase the death rate
  • r-Strategist Species: use less crowded and unstable ecological niches and produce many organisms; many will not survive to adulthood
  • K-Strategist Species: strong competitors in a crowded but stable niche and invest more heavily in fewer offspring; high probability offspring will survive to adulthood
  • Renewable Resources: replaced or recycled by natural processes
  • Nonrenewable Resources: those that are available in limited amounts and not replaceable
  • Greenhouse Effect: the trapping of the sun's warmth in a planet's lower atmosphere, due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface
  • Global Warming: when the greenhouse effect is amplified by excess carbon dioxide in the atmosphere
  • Pollution: contamination of soil, water, and air and is a result of human activity
  • Eutrophication: the addition of excess nutrients to a body of water in many cases due to an excess of nutrients that causes a bloom of producers
  • Acid Rain: air pollution containing sulfur oxides reacts with water vapor in the atmosphere to produce sulfur acid
  • Biodegradable: wastes/objects that can be broken down naturally by bacteria or other decomposers
  • Non-Biodegradable: objects/waste that stays in the environment for 100’s to 1000’s years
  • Biological Magnification (biomagnification, bioaccumulation): the increase in the concentration of a chemical as it moves through the trophic levels
  • Integrated Pest Management (IPM): an approach to reducing pests that consider and tries to reduce the environmental impact
  • Ozone Layer: high in the stratosphere and protects the earth from UV radiation
  • Threatened: when populations decline rapidly
  • Endangered: when numbers are so low that extinction is possible in the near future
  • Extinction: marks the end of the living members of a species
  • Invasive Species: also known as alien species; introduced or non-native species that have colonized a new area and causes harm to the environment