COMC-401 Lessons

The Circle of Life

Welcome back to Care of Magical Creatures! Our lesson today will not be about a creature. Rather, it will be about a topic that will frequently come up in the animal kingdom: ecosystems. Ecosystems play a huge part in the animal kingdom, because that’s what nature revolves around. Before we dive head first into learning about ecosystems, I’m going to provide you with a list of important definitions that will better your understanding of the material covered today.

Important Terms and Definitions

1. Abiotic - The physical or nonliving factors that shape an environment. This includes climate, rocks, soil, precipitation, sunlight, humidity, and wind.
2. Biosphere - All of the established ecosystems on a planet, or in a certain environment.   
3. Biotic - The living factors that shape an environment. Examples include animals, plants, fungi, bacteria, and protozoans. Biotic factors are directly dependent on the abiotic factors of the environment.
4. Ecology - The branch of biology that deals with the study of ecosystems.
5. Food chain - The hierarchical system in which a series of organisms are each dependent on the next as a food source.
6. Food web - The complex feeding network occurring in and between food chains of an ecosystem. This includes organisms that belong to multiple food chains.
7. Symbiosis - A relationship with two species living close to each other, usually benefiting from each other in some way.
1. Amensalism - One species is causing harm to another species, but is not benefiting off of the harm it is causing.
2. Commensalism - One species benefits, while the other is neither positively nor negatively impacted.
3. Competition - An interaction between species which causes the status of one to be lowered by the presence of the other.
4. Mutualism - Both species benefit from the symbiosis.
5. Neutralism - Two species interact, but nothing is lost or gained from this interaction.
6. Parasitism - The parasitic organism benefits, while the host is often negatively impacted.

 What is an Ecosystem?

The definition of an ecosystem is a biological community of interacting organisms and their physical environment. Everything in the ecosystem, from the smallest of organisms to the plants, plays a role in helping the environment thrive. Even if that role is the algae being eaten by the snail, who is then eaten by a toad.

As you might have seen in areas around you, or heard about from social media or news outlets, sometimes animals that are not native species are introduced into an environment. When this happens, it can wreak havoc on an ecosystem. Because there is already an established ecosystem, a new organism that is not normally living in the environment can change how parts of the ecosystem works, in particular a food chain and the food web. The food chains and food web are the bulk of an ecosystem; if one part of it fails or changes, the dominos do not fall where they are supposed to.

Introducing a nonnative species is not the only thing that can affect an ecosystem. Natural disturbances, like wildfires, can also affect an ecosystem. A forest fire can take down the vegetation that the organisms lower on the food chain consume. If there is not enough vegetation for those organisms, then there is not enough of those organisms for the carnivorous organisms to eat. It is very important when studying ecosystems to take natural disturbances into consideration when evaluating how the ecosystem has grown/or diminished or thrived or fallen.

The Scales of Ecosystems

Ecosystems come in several different varieties and sizes. There are two groups into which ecosystems can be categorized. The first is an aquatic ecosystem, or an ecosystem that takes place in a body of water, like a lake or ocean, or even something as small as a puddle. The second is a terrestrial ecosystem, or an ecosystem that exists outside a body of water on land. Often, an entire ecosystem is made up of both an aquatic and a terrestrial ecosystem, or an organism is included in both an aquatic and a terrestrial ecosystem.

There are three different sizes of ecosystems that we use. The first is a micro ecosystem, which is an ecosystem on a small scale, such as a tree trunk, puddle of water, or under a log or rock. These ecosystems are often a part of a larger ecosystem. The second is a meso ecosystem, which is a medium sized ecosystem, like a forest or a lake. These are the ecosystems that you will hear about most often, like the ecosystem of the Redwood Forest in California, United States. The last is a biome, which is an extremely large ecological area that spans a lot of land/water, or is a collection of ecosystems that have similar abiotic and biotic factors, like a rainforest. The best way to think of a biome is a not-quite-there ecosystem. They aren’t technically ecosystems, because they are defined by the abiotic factors, and how the living organisms in that area adapt to those factors. Different ecosystems are not separated by a dividing line or state/country border. They are separated by geographical barriers that change the ecosystem entirely, like a desert next to a forest, or a mountain range next to an ocean.

Please excuse this lengthy, but relevant, tangent on biomes. There are five different types of biomes, all which house important biotic and abiotic factors. Among each of these different types are subcategories. I will first discuss the definition of each kind, and then provide you with a chart that shows all of the subcategories. The first biome I would like to discuss is the aquatic biome. These biomes make up about 73% of the Earth. The living organisms in these biomes depend on the sunlight that comes through the water and water temperature, pressure, and salt content. When more sunlight is shining through, we tend to see more diversity in fauna or vegetation, and we see more algae and plankton. Organisms we see in these biomes are seabirds, a variety of fish and mammals, sea insects, crustaceans and mussels.

The second type of biome we are going to discuss is the desert biome. These biomes make up about 20% of the land on Earth. They are characterized by having little, less than 19.685 inches/50 centimeters of rainfall a year, to no rainfall. Desert biomes have very little vegetation or cloud cover, high temperatures, and low atmospheric moisture and humidity. The vegetation we see are cacti and shrubs, mostly because they are good at surviving long periods of time and holding water in their roots and bodies. The soil has very little to no organic matter and salt. Animals present in these biomes are small carnivores, insects, birds, lizards and snakes.

The third type of biome to discuss is the forest biome. These biomes make up about 30% of the land on Earth. They play an important role in climate control for the planet. These biomes are a carbon store and provide various raw materials we use on a daily basis. They have an incredible amount of biodiversity, housing tens of thousands of different species of living organisms. While temperatures are usually very high year round in these biomes, they tend to be lower towards the Earth’s surface. We see extremely high humidity levels, along with very loose, airy soils that are high in decaying matter and acidity. Trees, palms, ferns, and conifers are common plants to find in forest biomes. A variety of birds, insects, mammals, reptiles, and amphibians are present as well.

The fourth type of biome is the grassland biome. These are areas of land covered mostly in grasses, with a few trees scattered throughout. Often grassland biomes can develop into forest biomes, if there is no uncommon disturbance from animals or humans. We see moderate rainfall in these areas, with not enough to cause major flooding usually. We see a variety of grasses and shorter trees. We see a variety of mammals, like big cats, elephants and buffaloes and small herbivores, insects, birds of prey, and reptiles.

The final type of biome we will discuss is the tundra biome. These biomes cover about one fifth of the land on Earth. They have very little rain and freezing temperatures. Any plant growth is very short and squat, and grows in bunches, and is mostly mosses, lichen and heaths. We see a variety of small herbivores, birds, large carnivores like polar bears and foxes, fish, insects and aquatic mammals like seals. In the Alpines, we see mountain goats and sheep as well. There are ponds formed, due to the constant perma freezing.

The Ecosystem Hierarchy

Individual organisms, which then build populations, which then build communities, are the building blocks to creating an ecosystem. Individual organisms, like the goldfish in the diagram, are just that; a single organism. These single organisms all come together to make a population. They will vary in genetic makeup, like how we can have different colored hair and eyes, but they are all the same species. A community is all of the populations of species in a specific area. In the diagram, you see we have a goldfish population, a crab population, a jellyfish population, and a larger fish population. These communities make up ecosystems, which in turn make up biomes and the biosphere of the planet or that particular region.

The Food Chains and The Food Web

While we briefly discussed food chains and the food web earlier on in the lesson, I would like to come back to them for a moment. The food chains and food web of an ecosystem are the essential feeding relationships that enable the biotic factors to continue shaping an environment. The food web of an ecosystem is how all of the food chains work together. The provided image shows a food web, and how different organisms are all involved in different food chains. How many food chains can you identify in the image?

In a food chain, we have different levels called trophic levels. When we reference an organism’s trophic level we are referring to their place in their food chain. There are eight different trophic levels. The first are the producers, or the vegetation and the sun. They use photosynthesis to make their own energy. The next level are the primary consumers, or the herbivores that consume green plants. These include ruminant animals like cattle and sheep, and insects like caterpillars and ladybugs. We then come to the secondary consumers, or those that eat the primary consumers, along with other animal and plant matter. These include some different mammals, like cats, and reptiles, like snakes. We then move on to the tertiary consumers, which are animals that eat the secondary consumers. We have the last of the consumers, the quaternary consumers, which consume the tertiary consumers. At the top of the food chain, we have the predators. These animals have very little or no natural enemies. They rule their ecosystem, and eat their prey which comes from any of the lower levels of the food chain. Humans can actually be considered predators, however, lions and sharks are better examples. Now, you might have noticed I said there are eight levels, but only listed six. These last two do not fall into an exact place in the ecosystem, rather they help the life cycle start over. Detritivores consume dead and decaying animals. Hawks, vultures and worms can all be considered detritivores. What matter is not eaten by the detritivores is then broken down by the decomposers, or bacteria and fungi, and becomes the organic matter in the soil to help the green plants grow, and the cycle starts all over again.

The Year-Long Project

Now that we have covered ecosystems, I am pleased to start the discussion on the project that will be for the entirety of Year Four. After learning about ecosystems, I hope you have some understanding of what goes into an ecosystem, because you will be developing your own ecosystem. Now, I’m sure you have many questions about this, and so please review the information below to help understand the project.

1. You will select at least one but no more than three magical creatures that have been covered during Care of Magical Creatures Years Two through Four, an unlimited number of mundane creatures, and an unlimited number of plants. You may have to do some outside research to determine a kind of plant or mundane creature to include in your ecosystem. Feel free to come to myself if you are struggling for ideas!
2. While determining the kinds of creatures you will have in your ecosystem, you will also have to determine what environment your ecosystem will be in. Which biome would it fall into? Do you have a specific region of the world where your creature is native to?
3. Is there any symbiosis in the relationships between creatures? For example, you choose to use the mundane creature like a leech, and the magical creature the Grindylow. The leech and the Grindylow would be a form of parasitism, because the leech is sucking blood out of the Grindylow, and the Grindylow ends up with a sore that could potentially start a horrible infection. It is not necessary to have or identify a relationship, but if you realize one is present we encourage you to discuss it.
4. Describe the abbreviated food chain. You don’t need to have a creature from each level, but discuss which trophic level you feel each creature you selected falls into and why.
5. There will be multiple ways to submit the project, of which will be discussed in Lesson Six of this year, so make sure to save all of the assignments based on the project because they are the check in points to help you form and develop your ecosystem.

Closing

Hopefully this answers any questions you have right now, however, you are always welcome to owl myself for clarification and with additional questions. You will have an assignment related to the final project, as well as a worksheet on ecology to complete today. I will see you next time to learn about some very spooky creatures. Until then, good luck on your assignments and other courses, and as always, don’t hesitate to contact me for help, or to just discuss your thoughts on the lessons and content covered.

Lesson content written by Professor Elizabeth Anne

All pictures are found using the Google Images search engine, and belong to their owners. The chart showing the different types of biomes was made by Professor Anne using Google Draw.