Ancient Oceans

Marine arthropods (related to lobsters and crabs) that lived in ancient seas (now extinct). They had a hard exoskeleton and are often used as index fossils for dating rock layers.  They looked similar to a horseshoe crab.

• trilobite

• ammonites

• brachiopods

• crinoids

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

Coiled, shell-like cephalopods (related to octopus, squid, nautilus, cuttlefish) that lived in the seas (now extinct). Their spiral-shaped shells are commonly found as fossils.

• trilobite

• ammonites

• brachiopods

• crinoids

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

Marine animals with two shells that resemble clamshells (they exist today). They were abundant in ancient oceans and have a distinct hinge line.

• trilobite

• ammonites

• brachiopods

• crinoids

Tags

NGSS.MS-LS4-2

Also known as sea lilies, are echinoderms (related to sea urchins) with feathery arms (they exist today). Their stem-like structures and fossils are common in some North American rock formations.

• trilobite

• ammonites

• brachiopods

• crinoids

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

A diverse group of mollusks (invertebrates where most have a shell), including snails and slugs, which were present in ancient oceans and left behind distinctive coiled shells.

• gastropods

• icythosaurs

• mosasaurs

• plesiosaurs

Ancient marine reptiles that resembled dolphins (they were not dinosaurs). It had a streamlined, fish-like body, making it well-suited for life in the ocean.

• gastropods

• icythosaurs

• mosasaurs

• plesiosaurs

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

Massive sea reptiles that lived alongside the dinosaurs. Resembling a large, lizard-like creature, it was perfectly adapted for life in the ocean. They were strong swimmers and primarily dined on fish and other marine animals.

• gastropods

• icythosaurs

• mosasaurs

• plesiosaurs

A type of prehistoric marine reptile that lived during the age of dinosaurs. It was characterized by its long neck, a body resembling that of a turtle, and flippers.

• gastropods

• icythosaurs

• mosasaurs

• plesiosaurs

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

A large inland body of water that stretched from the Gulf of Mexico to the Arctic Ocean, dividing North America into two landmasses.

• western interior seaway

• north american waterway

• grand interior seaway

• eastern interior seaway

Tags

NGSS.MS-ESS2-2

NGSS.MS-ESS2-3