Ecosystem Portfolio:

Freshwater Ecosystem:

Biotic: Animals

-Vole -Spoonbill - Swan -Frog -Catfish -Angelfish -Beaver

Biotic: Plants

-Water Lily -Spikerush -Cattails -Yellow Willow -Algae


-Constant Rain - Dense air -Clay/Mud -Sunlight -Rocks

Carrying Capacity:

Carrying capacity is the amount of organisms and ecosystem can hold usually measured by years. It depends on how many resources there are for the organisms to survive. The resources every organism needs to survive is food, water, shelter, and space, which is how much space it needs to gain the other resources.

Example: A beaver's survival in the wild requires for them to find an abundance of trees to create their shelter, and gain food that is in their space, or lake created by a beaver's dam.

Beaver dam surrounded by trees

Limiting Factors:

Limiting factors are realistic factors that limit the resources needed for the survival of an organism. A limiting factor can be severe weather in an ecosystem (drought, flood, etc.), or for specific animals, predators and anything that may threaten the amount of resources necessary for an organisms survival.

Example: The catfish eats the crayfish, who are usually abundant.

There was a decrease in crayfish this year so the catfish did not aquire any.

Energy Roles:

Producers are the start of any food chain/web/pyramid. They convert the suns energy(Radiant Energy) into chemical energy. 90% of chem. energy is used to keep the organism alive while 10% is passed onto the next organism. Without producers, organisms would have no way of gaining chem. energy, which would cause all organisms to die. Below is a freshwater food chain starting with a producer, Algae.

Producer- Algae

Who is then eaten by...

Primary Consumer- Pond Snail

Who gets munched on by

Secondary Consumer- Ducks

And ducks just so happened to get eaten by.

Tertiary Consumer- European Pike

They looked small to me until I asked google,(enter european pike on images to see them) until i saw the proud fishers, they eat ducks

Below I found a kind of funny article on a pike, and I'd like to share it. It also supports that a pike will eat a duck, if you'd like to know.

Food Webs:

Though food chains are short and sweet, they're not the best source to base realistic data on. Not all algae is only eaten by pond snails, and not all snails are eaten by ducks. Therefore, there are more realistic sources, food webs. A food web is many food chains all in one that show more options on what an organism eats or may be eaten by.

Here is a freshwater food web.

Now imagine removing the source(s) of this food web. If we remove the algae, it would have a direct effect on the organism(s) that eat algae. Soon this would lead a chain event (get the pun?) to the other organisms in the food web. Yes, there are other sources but without the algae more organisms would rely on the other source(s) causing the amounts to decrease which would again lead to a decrease of organisms in that freshwater ecosystem.

Energy Pyramids (Trophic Levels):

Here is an energy pyramid of the food chain i had created before

Energy Pyramids are created as a pyramid to show the energy flow in a visual representation. Towards the base, it is much larger because there is more energy there. There is more energy there because the producers have converted the radiant energy into chemical energy. Towards the top it gets smaller and smaller because there is less energy being passed on. The energy is passed on throughout the levels by 10% each level and leaving 90% to keep the organism alive. This is why energy pyramids need a 1,000 kcal. start to keep one tertiary consumer alive.


Also glucose is inside the leaves (which is where everything happens)

6 CO2+ 6 H2O-> C6H12O6 + 6 O2

Photosynthesis is a plant process that requires Carbon Dioxide, Water, and Radiant energy to transform Radiant energy into Glucose (plant food), while releasing Oxygen into the atmosphere as a waste product. This chemical process takes place within chlorophyll, which is inside a plant's chloroplast cell.

Energy Transformation taking place in plant leaves.


Tropism is plant movement for survival, whether it be towards (positive tropism) or away (negative tropism), to/from  water, gravity, light, or touch. An example for tropism in a freshwater ecosystem would be water lillies' roots growing beneath the mud in a pond, geotropism, the roots grow downwards to root the plant, collect nutrients, and also take in a small amount of water (the bottom of the leaves can also take in water).

Water lillies stems shown above while the roots grow in the mud showing geotropism, the roots grow downwards

These tropisms help the water lily survive by giving the plant nutrients and letting it gain resources needed. It also keeps the plant from floating away onto the shore away from resources and towards animals that may eat it.

The Role of Decomposers:

Decomposers play a vital role in the freshwater ecosystem. They are made up of a team of bacteria and fungi. These decomposers assist the ecosystem by decomposing dead fish into nutrients that the ecosystem would then resuse.

Ex: Earthworms, Freshwater snails, and insect larvae.

I was not able to find a picture of a fish decomposing that wasn't gross so i chose a more cartoonish version.

PLEASE NOTE: I'm sorry for the lack of detail found in this area. There was not many resources for what i was looking for and i apologise. I was trying to keep this as "water based" as i could but that choice made resources limited so again, I'm sorry.


Adaptions are a very important part of an ecosystem (or biome). They are what let an organism survive according to the abiotic factors. Without adaptions, there would not be a unique ecosystem to all abiotic features in different parts of the world. No organism would survive the desert, and no bird would touch the sky, they would not have any special details to let them. There are two types of adaptions, behavioral and structural. Both foreshadow their actual meaning. Behavioral adaptions are adaptions that assist an organism on what to do. It gives organisms the instincts that help it survive. Structural adaptions are adaptions that are part of the organism. They are physical features that help them survive in their specific envoirment.

Adaptions that are necessary to let an animal survive in the freshwater ecosystem is the ability to withstand water. Animals that are regularly in the water but can go on land/air need a form of protection against the water and its currents. Animals in the water need the ability to "breathe" freshwater instead of saltwater. Those animals would also have to be adapted to the water temperature. As for plants, they would also require the resistance to water or else they would "drown". Also, like most animals, they would have to be adapted to the freshwater and temperatures.

Yes, again, water lillies have the adaption of taking in water through the bottom of their leaves
This animal has the adaptions of water resistance, swimming, and cuteness (sadly the last one isn't an adaption).

Let's say we were to relocate an animal from the freshwater ecosystem. It would be abruptly taken from its enviorment and be moved into a completely new one. This new enviorment does not lack in water, but rather has a bit too much. The water in its new enviorment has an extremely different temperature and is no longer fresh. This animal has the ability to swim, which will help it partcially, but none of the food there is part of this animal's food web. It searches for something familar but finds nothing. By that time it's getting dark and the animal has yet to find food, fresh water, and shelter. As the night falls, the animal is worn out from swimming all day and not recieving food. It continues its quest the next day, with the same results, and the day after. Finally, it is put out of its misery in the new not so fresh but salty water of the ecosystem.

Natural Selection:

Natural selcetion is when a type of organism develops new adaptions according to the abiotic factors in their enviorment. This assists the species by letting the organism with traits that let it survive, survive and reproduce. Without natural selection, there would not be specialised adaptions sepecific to a certain ecosystem.

Ex: Salmon have the adaption of migration to freshwater from saltwater where predators cannot follow them to lay their eggs. They gained this ability by natural selection, having the new generations be raised in freshwater streams then go into saltwater once older.

Comment Stream

2 years ago

Pictures are blurry but if they were not good job!😜

2 years ago

I'll try and fix that but thanks 😊

2 years ago

@calliealford whoops forgot tag

2 years ago

I agree, it would be great to find more clear pictures.

2 years ago

try to find better pictures

2 years ago

finish step 7 😀