5. Diversity in the Ocean

In the ocean there are lots of unique life cycles, adaptations, and relationships that are not seen on land. The ocean has lots of diversity which means that there are many different things left to be discovered.

Life cycles are the changes that an organisms experiences as it grows up. The human life cycle is a simple one. You start out as a baby then a toddler, a child, a teenager, and adult and then a senior.

During some life cycles, an organism may change it's entire body as it grows up. Lets look at salmon as an example. Salmon eggs are laid in freshwater streams and buried by rocks and debris to protect them from the current and predators. As the eggs develop, eyes can be seen inside of them. This means the eggs are close to hatching. Once they hatch, the salmon Fry keep their egg yolk with them for food and nutrients.

After the fry absorb their yolk sac and develop their scales, they become Smolt. Now they finally look like salmon as we know them but they are still very small. Smolt will start to migrate to the ocean, all while avoiding dangerous predators like a heron looking for it's next meal.


Finally, the salmon reaches the ocean. It is considered a Juvenile Salmon at this stage and will focus on catching smaller fish to eat so that it can grow bigger. Once it reaches the age where it can lay eggs itself, it is called an Adult Salmon. Adult salmon will return to the same stream they hatched in.

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The salmon life cycle is very special because the fish change home and shape during their life. This is something only found in the ocean.

In the ocean, we also see animals with special adaptations. Adaptations are characteristics or traits that help an animal survive, like how you have special thumbs to pick up your food with. In the ocean, these adaptions can change depending on where an animal is found. Sometimes it will be physical features in an animals or it might be a special way that they act.

For example, smaller fish living in the wide, open ocean often swim together in a behavior called schooling. Take a look at this picture. Why would these fish want to swim together when they live in a habitat like this?

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Fish that live in the big open ocean could face a predator coming from any direction. By schooling together these fish have a better chance of spotting dangers or having their neighbor eaten instead of them! This is a behavior adaptation for surviving in the open ocean.

Sometimes these adaptions are physical. Beluga whales live in the cold Arctic ocean and have many different adaptations for surviving in this extreme environment. One of their biggest adaption is their blubber! Blubber is a thick layer of fat that surrounds the beluga's body to keep them warm, like when you wear a thick jacket when it is cold outside.

Take the Will I Survive? quiz to learn more about these adaptations and test your knowledge!

There are lots of different kinds of habitats, like there are lots of different kinds of animals. These habitats are described by the amount of salt, light, heat, and pressure that they have. The Arctic ocean, covered with ice and cold water, is very different from a warm, tropical coral reef. Some animals live among the rocky ocean floor while others live in the wide, open ocean where there is no where to hide. Some animals even live so deep down that there is no light and a huge amount of pressure. What sort of adaptations do you think these animals would have?

The ocean also supports many different kinds of relationships between animals. In this video, the hermit crab helps the sea anemone to get around and provides food while the sea anemone provides the hermit crab with protection from predators.

Even though the ocean has a wide diversity of plants, animals, and habitat, not all oceans can support life. All organisms have a comfort zone in which they like to live in. That is why you do not see tropical fishing living up in the Arctic. Some areas of the ocean are so extreme that nothing can live there at all.

In the next section, we are going to talk more about how humans impact the ocean and how the ocean impacts humans. Before moving on, take the Diversity of Organisms quiz to review your knowledge and earn your badge. You can find the quiz HERE. After you complete the quiz you may move onto the next section: Oceans and People.

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