Intertidal Ecosystem

Biotic Factors: Anything that lives or lived in an ecosystem


Abiotic Factors: A non-living condition or thing

Salt water
Very hot to near freezing temperature
High and low tides
Well sorted sediment

Carrying Capacity: Largest number of individuals of a species that an environment can support

Food, water, shelter, and space are needed for a population to survive.

Limiting Factors: Any factor or condition that limits the growth of a population in an ecosystem

Competition for space in the intertidal zone is important because it is the one thing that can claim survival for an organism. Food is somewhat abundant in the intertidal zone. Some organisms still compete for food but the major limiting factor is space.

Although there's a lot of kelp, if limiting factors such as the crab eat the fish, it could easily decrease the fish population.

Energy Roles

Plants, such as seaweed, in this ecosystem are considered primary producers because they give nearly all of the energy that other species need to survive. They make their own food from the sun through photosynthesis.

Consumers may obtain their energy directly from producers, from other consumers or from a combination of both. A herbivore in the intertidal ecosystem is the urchin, an omnivore is the crab, and a carnivore is the starfish.

Decomposers (bacteria and fungi in this ecosystem) get their energy from consumers' remains when they are deceased.

Food Chains and Food Webs

A food web has all the different opprotunities in an ecosystem, better presenting the relationship of each living thing to another within that ecosystem.

If I removed the crab from the first food web, the unknown fish, Goby, and Lizardfish populations would increase without that type of predator to eat them. The bird population would decrease without their prey to eat.

Trophic Levels and Energy Pyramids

The energy is shaped as a pyramid because of how it gets smaller at the top, representing the 10% of energy being passed down from the lowest organisms to the ones on the top.

Producers are at the largest level because they are given the most amount of energy, and top predators are at the smallest level because of how they end up with a small 10% of energy.


The chemical equation for photosynthesis is 6CO2 + 6H2O ------> C6H12O6 + 6O2.

Water(H2O), Carbon Dioxide(CO2), and light are all needed for photosynthesis.
Glucose(C6H12O6) and Oxygen(O2) is produced by photosynthesis.

Photosynthesis takes place in chloroplasts.

The energy transformation in photosynthesis is radiant energy(sunlight) being converted to chemical energy(glucose).


Tropism is the turning or bending movement of an organism toward or away from an external stimulus, such as light, heat, or gravity.

Algae is an example of a plant that uses phototropism; it grows and bends in response to light. As it grows in abundant sunlight, algae and other intertidal plants support an entire food chain of animals.

The Role of Decomposers

If there weren't any decomposers in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up. Decomposers are there to break down dead plants and animals, along with their waste.


An adaptation makes it possible for an animal to live in a particular environment and in a particular way. It may be a physical adaptation, like the color of its fur, or it may be the way the animal behaves, like migrating or hibernating for the winter.

An example of behavioral adaptations are like how crabs, marine snails, and bivalves, have thick, tough outer coverings to slow evaporation. An example of physical adaptations are mussels and leaf barnacles and how they cluster together to reduce individual exposure.

If an organism is placed into an environment that it is not used to, the organism would not be able to find food, water, shelter with the adaptations it has. It wouldn't be able to survive in the new ecosystem.

Natural Selection

Natural selection is the process by which species adapt to their environment. If natural selection does not occur with the organism, it will not adapt and not be able to survive.

Comment Stream

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3 years ago

Same as trey, you need to specify the abiotic factors more. Good pictures though.

3 years ago

@calliealford Thanks, Callie-coo!

3 years ago

I like your starfish picture

3 years ago

@jimmiewatson and @journeywinkle Will do! 😁

3 years ago

Pretty pictures and I think you did a good job 😊

3 years ago

Looks good...add a few more abiotic factors.

3 years ago

finish energy pyramid

2 years ago


2 years ago

good i like it alot

2 years ago

Under the seaweeds on the rock picture you need to put an as after the such. Other than that great job.