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Ecosystems and Ecology

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Ecosystems: What Are They and How Do They Work?

An ecosystem is made up of all the different species that live together in one habitat, along with all the physical aspects (soil, water, weather, etc.) of that habitat.

Why do scientists study ecosystems? To learn about how things are connected, as well as what humans can do to better protect the environment. But why protect the environment? Because what affects one part of the environment, affects us all. When even just one species becomes extinct, or is taken into new areas with no natural predators, unpredictable changes can take place.

In this unit on Ecology, we'll explore the subject of ecosystems. What are they? How do they change? How does energy flow through them? What are food chains, food webs, energy pyramids, and biogeochemical cycles?

Our Homeschool Co-op is doing a high school level class in Biology this year. Our main textbook is Holt Biology. The sections on this page accompany chapter 16: Ecosystems in Holt Biology. Whether you're in our homeschool co-op or not, you're welcome to follow along as we explore and marvel at the world around us.

Holt Biology

by: George B. Johnson, Peter H. Raven

Amazon Price: $35.00 (as of 05/31/2012)
Used Price: $3.99

This book is available in both hardback and CD. Also, it's available new and used. Visit the link above to get the prices of different formats.

What Is An Ecosystem?

16.1 in Holt Biology

1. Watch the two youtubes below.
2. Read section 16.1 in Holt Biology and answer the review questions in the book.
3. Important ecosystem vocabulary and information can be found below the youtubes.

Ecosystems The Biosphere: by kmehtas | video info

4 ratings | 673 views

curated content from YouTube

Ecosystems Vocabulary

for section 16.1 in Holt Biology

There is a lot of vocabulary in this section. Making and using flashcards of the vocabulary may help.

Ecology - the study of how living organisms interact with one another and with their physical environment.
Habitat - the home to a particular population of a species
Community - The species that live together in one habitat
Ecosystem - The community and the physical environment (soil, weather, water, etc.)
Abiotic Factors - the physical components of a habitat. The non living parts of the environment. (rocks, minerals, water, wind, weather, etc.)
Biotic Factors - Living things. Organisms.
Biodiversity - This includes all the variety of organisms, their genes, and their communities and ecosystems in a particular region.
Pioneer species - The first organisms to live in a new habitat, such as a new island formed by an underwater volcano. These are usually small and fast-growing plants. They help prepare the ground for later species.
Succession - the progression of species, beginning with the pioneer species (that begin growing when the habitat is new) and moving on to other species (as the habitat ages some). The first species pave the way for later species to follow by helping to create or enrich the soil. In succession, one species replaces another as the new species grows taller and blocks out the sun.
Primary Succession - Primary succession takes place in a brand new habitat (such as a new island formed by an erupting volcano), where no life has been living.
Secondary Succession - Secondary succession takes places in areas that have had previous growth and already have soil. If a fire burns a forest, secondary succession will take place and gradually rebuild the area into a forest.

Other Important Information About Ecosystems

Everything is connected. When something happens to one part of an ecosystem, it affects other aspects of the ecosystems as well.

Ecosystems can be size, from a rotting log or puddle on the ground, to an ocean. (Look up types of ecosystems.) A scientist will decide on the size of the ecosystem that he/she wants to study, based on what he/she is researching.

Ecosystems can change over time. For example, if fire rips through a forest, the forest may become an empty field for a while. Gradually seeds will be blown there by the wind, or dropped there by birds passing over, and small plants will start to grow again. Gradually, other plants will begin to go there, eventually replacing the original plants, only to be replaced themselves by yet other plants. Of course, as the type of plants growing there changes, so do the types of animals living there.

Succession Worksheet

Video on Ecological Succession

Energy Flow In Ecosystems

16.2 in Holt Biology

1. Watch the youtube below.
2. Read section 16.2 in Holt Biology and answer the review questions in the book.
3. Important energy flow within an ecosystem vocabulary and information can be found below the youtube.

How Ecosystems Work | Biology | Ecology: by greatpacificmedia | video info

68 ratings | 57,711 views

curated content from YouTube

Energy Flow in Ecosystems Vocabulary

16.2 in Holt Biology

Primary Productivity - the rate at which photosynthetic organisms can produce food from photosynthesis. This rate determines the amount of available energy in an ecosystem.
Food chain - the path of energy from the sun to producers to consumers to larger consumers, etc.
Tropic level- The various levels in a food chain. (The producers, the consumers, the consumers that eat those consumers, and so on)
Producers are organisms such as plants, algae, and bacteria, that get energy directly from the sun. This is the first trophic level.
Herbivores - This is the second tropic level. These are animals that eat plants.
Consumers are organisms that eat plants or other living things in order to gain energy. Both herbivores and carnivores are consumers.
Carnivores - Animals that eat other animals. This is the 3rd trophic level.
Omnivores - Are animals that eat both plants and animals.
Detritivores - Worms and decomposers who get their energy from eating wastes and dead animals.
Decomposers - Bacteria and fungi decompose things that were once living. This helps release nutrients back into the environment.
Food Web - An interconnected group of food chains.
Energy Pyramid - An Energy pyramid is a diagram that shows how energy flows through ecosystems. The lowest trophic level (producers) is on the bottom of the pyramid. Above that are the consumers that eat the producers. About that are the consumers that eat those consumers, and so on.)
Biomass - This is how biologists measure the amount of energy that is in the trophic levels. It's the dry weight of tissue and other organic matter.

More Information About Energy Flow.

All energy comes originally from the sun. Plants capture that energy. Herbivores and omnivores that eat the plants get some of that energy. Organisms that eat those animals get energy from them. In this way, energy that originally came from the sun is passed on along the food chain.

As energy is passed from one organism to another, some energy is given off into the environment as heat. Therefore, the amount of usuable energy decreases as the energy passes through the ecosystem. Only about 10% of the energy in one organism gets stored in the body of the next organism. For this reason, there is a limit to the number of trophic levels that an ecosystem can support. Most land ecosystems have only 3, or sometimes 4, trophic levels.

Cycling of Materials in Ecosystems

The Carbon Cycle, The Nitrogen Cycle, The Phosphorus Cycle

Cycling of Materials in Ecosystems: The Carbon Cycle, The Nitrogen Cycle, The Phosphorus Cycle

6.3 in Holt Biology

The video I had here was removed from youtube last night due to copy right violations. I'll get a replacement available asap. 2/17/12
1. Read the chapter in the text.
2. Answer the review questions.

Cycling of Materials In Ecosystems Vocabulary

16.3 in Holt Biology

Four substances are very important in maintaining ecosystems: carbon, nitrogen, phosphorus, and water. All living organisms require carbon, nitrogen, phosphorus, and water, as well as hydrogen and sulfur, in large quantities. Water, carbon, nitrogen, and phosphorus pass from non living things to living organisms and then back into the environment again.

Biogeochemical Cycle - Biogeochemical cycles are the pathways that various substances take through the environment. For example, we have the water cycle, the carbon cycle, the phosphorus cycle and the nitrogen cycle.
Ground Water - This is water in the ground.
Water Cycle - You're probably familiar with the evaporation and condensation part of the water cycle already, but did you know that plants are part of the water cycle as well? Water is taken up from the ground into the roots of plants. Later that water evaporates (from the leaves) back into the environment.
Transpiration - is the process in which water evaporates from the leaves of plants.
Carbon Cycle - Carbon dioxide (from the air or water) is used by plants during photosynthesis. That carbon dioxide is later recycled back into the environment in one of three ways.
a. Cellular Respiration - This is the process almost all living organisms use to turn food into useable energy. In the process, carbon dioxide is given off as a waste product.
b. Combustion - Combustion means burning. As fossil fuels (coal, oil, and natural gas) are burned, they release carbon into the environment.
c. Erosion - As sea shells turn into limestone, and the limestone erodes, the carbon that was in the shells is returned to the environment.
Phosphorus Cycle - Phosphorus is used by living thing in ATP (like a rechargable battery in living organisms) and DNA. Soil and rocks contain phosphorus which gets passed on into water. This phosphorus conatining water gets taken up by the roots of plants, and is later passed on to the animals that eat those plants, and then to the animals that eat animals that ate plants.
Nitrogen Cycle - There are four main stages in the Nitrogen Cycle.
a. Assimilation - is the process in which plants absorb and use nitrogen in making organic compounds.
b. Ammonification - As plants and animals die and begin to decay, bacteria create ammonia. Ammonia has nitrogen in it. This process is called Nitrogen fixation
c. Nitrification - is the process of making nitrate from ammonia.
d. Denitrification - Is the process of changing nitrate into nitrogen gas.

Biological Communities - Symbiosis, Niches, and Biomes

You'll Find The Next Page In This Biology Series Here

Biological Communities - Symbiosis, Niches, and Biomes

Biological Communities - Symbiosis, Niches, and Biomes: This is the next page in this biology series. It covers symbiotic interactions between species, as well as niches and biomes.

Biology

A list of units in this series

Homepage: Biology: Information, Videos, and Labs

Unit 1 on Cell Biology
Biology Labs, Activities, Videos, and Study Guides About Cells (Photosynthesis, Mitosis, Cell Organelles, and More)

Unit 2 on Genetics
Labs, Information, And Videos For High School Students Studying Genetics.

Unit 3 on The History of Life on Earth
The History Of Life On Earth.

Unit 4 on Ecology
Ecological Principles / Populations
Ecosystems
Biological Communities - Symbiosis, Niches, and Biomes
Global Changes And The Environment

Unit 5 on Diversity
An Introduction to Taxonomy - The Kingdoms and Domains Of Life
Learning About Viruses And Bacteria
Protists: Paramecium, Amoebas, Algae, Diatoms, Euglena, and Others
The Fungi Kingdom

Unit 6 on All About Plants
The Plant Kingdom

Unit 7 on The Animal Kingdom: Invertebrates
The Animal Kingdom - An Introduction
Sponges are Simple Animals
The Cnidarians: Jellyfish, Sea Anemones, Hydrozoans, and Corals
Earthworms, Christmas Tree Worms, Leeches, and Other Annelids

Check back later for additional biology units!