This right here is a picture of the marine food web. This shows how all of the animals rely on others for survival. Every organism has their own niche. A niche is sort of like a clique or a group of the same types of organisms.
Plankton: Plankton are a diverse group of organisms that live in the water column and cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales. Without the plankton many of these animals would not be able to survive because many fish rely of other fish for food and if the ocean fish don't eat then the whales and other larger fish will suffer.
Types of Plankton:
Phytoplankton , autotrophic, prokaryotic or Eukaryota algae that live near the water surface where there is sufficient light to support photosynthesis. also, cyanobacteria, dinoflagellates and coccolithophores.Zooplankton, small protozoans or metazoans that feed on other plankton and telonemia. Some of the eggs and larvae of larger animals, such as fish, crustaceans, and annelids, are included here.
Bacterioplankton, bacteria, which play an important role in organic material down the water column
Ocean Fish:
Ocean fish are just the fish that live in the ocean, these are one of the main providers for all of the other creatures. Pelagic fish are a main fish in the ocean. These fish usually travel in schools. This is important for the other fish because they need food to eat.
All organisms have different adaptations such as what they eat, where they live, who they fit in with. Over time fish have changed drastically, between their physical appearance, adaptations and much more. They have changed with their looks a lot they have evolved a lot over time with how they protect themselves and their schools around them too.
All organisms have different adaptations such as a shark and a penguin. Sharks are organisms that have developed over time. The picture below shows how the evolution of a shark has changed over time.
This shows how the shark started out. It looks kind of like a dinosaur when it started out. Over time it evolved to having fins instead of feet, and instead of a long bill with teeth they now have a shorter snout with sharp teeth. Another animal that has evolved over time was the penguin. Penguins now live in cooler habitats and eat mostly fish that they catch in the ocean. Penguins have tall bodies, and shorter beaks where as years ago they had fatter and sat on their bottoms a lot and had a longer beak. All organisms have different adaptations depending on what they need and how their bodies adapt to certain climates and surroundings. All animals need different things to survive, that's just how it is. With out animals and evolution the world would not be where it is today, we need animals to survive.