The ocean teems with life, from the blue whale to the pygmy seahorse to brain coral. But did you know that the ocean is also home to plankton? These marine organisms drift with ocean currents. And many of them are too small for humans to see. There are two kinds of plankton: phytoplankton and zooplankton.
Phytoplankton are microscopic organisms that use sunlight to grow and make food. They also produce most of the oxygen we breathe. Phytoplankton are just as important to life on Earth as rainforests!
Zooplankton are tiny marine animals that can't swim strongly against the ocean current. Some are permanent drifters in the sea. Others are actually larvae: baby forms of larger marine animals. As these ocean babies grow up, some gain the ability to swim. Some become able to propel themselves through water. And some eventually settle out to live on or near the ocean bottom. The adults they become no longer drift with the currents. So, they are no longer considered plankton.
These marine adults can look very different from the larvae they once were. Can you find their plankton baby pictures?
1
I’m an ocean sunfish, the heaviest bony fish in the world. I can weigh as much as 1,000 kilograms (2,200 pounds)! But when I was a baby, I was as small as the head of a pin. And I had a spiky, star-shaped covering.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
My mom laid about 300 million other eggs along with the one I hatched from. That’s a lot of siblings!
Question 1 of 8
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2
I’m a bluefin tuna. I swim fast: up to 70 kilometers (43 miles) per hour. And I migrate vast distances to feed and to lay eggs. I can grow as big as 3 meters (10 feet), but when I was a larva I was the size of a lentil.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
As a little fish, I hung out in schools with youngsters my own size.
Question 2 of 8
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3
I’m a flounder. I lie on my side on the seafloor waiting to ambush prey. Because my left side always faces up, both my eyes are on the left. But when I was a baby, I had eyes on both sides, like other fishes.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
As I grew up, I lost my bright colors—but that’s okay. Now I can change the color and pattern of my skin to help me hide on the seafloor. I can look like sand one minute, and a rocky bottom the next!
Question 3 of 8
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4
I’m a sea star, and I live in shallow waters. I get my name from my five spiny arms that form the shape of a star. But as a larva, I looked more like an alien with flowy tentacles. And I was covered with about 100,000 microscopic hairs called cilia. I used them to move around in the water.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
Having thousands of cilia was nice, but my adult arms work better now that I’m big. If somebody bites off an arm, I can grow a new one!
Question 4 of 8
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5
I’m a dog whelk, and I live on rocky shores. My strong, hard, pointed shell protects me from birds and crabs. When I first emerged from my egg capsule, my shell was thin and almost transparent.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
As a new hatchling, I was so good at crawling that scientists called me a “crawl-away.”
Question 5 of 8
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6
I'm a crab but my long legs make me look like a spider—that’s why I’m called a spider crab. I live in vents and holes deep on the ocean floor. My hard shell helps me scrape up algae and pry open mollusks to eat. But when I was a baby I had no shell. I was transparent!
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
Until I hatched, my mother carried me and other fertilized eggs on her abdomen.
Question 6 of 8
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7
I’m a parchment worm. I live in a papery tube buried in sediment. When I wave water with my fan-like segments, plankton stick to my mucus. Yum, lunch! As a larva, though, I drifted free. I didn’t need spines yet to dig with.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
Living in a tube is a big change from drifting. But don’t bump my tube! If you do, I might burp out glowing blue mucus.
Question 7 of 8
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8
I’m a tube anemone. I may look like a plant that lives on the ocean floor, but I’m actually a carnivorous animal. I have hundreds of tentacles that I use to grab prey, such as small crustaceans that swim near. I started life drifting with ocean currents as my tentacles developed.
Can you find my plankton baby picture?
Nope. Try again!
Yup! That’s me!
Once I was big enough, I burrowed in sand or mud until I reached solid rock I could grab with my foot. Others like me also live in crevices in the rocks.
Question 8 of 8
Nice try!
Swimmingly!
Swimmingly!
What a splash!
You got out of 8 right on the first guess.
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