Life in the Ocean

Beth Roland

Eighth Grade Science

Three Groups of Marine Life

• The three groups of marine life are plankton, nekton, and benthos.

• Aquatic life in the ocean is divided based on where an organism lives and how it moves.

Marine Life

plankton Nekton benthos

Plankton

• Organisms that float or drift freely near the ocean’s surface are called plankton.

• Often microscopic, plankton are an important food source for many organisms– Phytoplankton- plant-like

plankton that can photosynthesize

– Zooplankton- animal-like

Nekton

• Nekton are organisms that swim freely in the open ocean.

• Examples include mammals such as whales and dolphins, sea lions as well as a great variety of fish

Benthos Organisms

• Benthos are organisms that live in or on the ocean floor

• Examples include: crabs, starfish, worms coral, sponges, seaweed and clams

Food Chain vs. Food Web

• Food Chains show a linear path from one animal to another

• Very simplistic and can be easily understood

• Food Webs show various organisms that are eaten by other organisms

• Allows one to see the interconnectedness of species and how they depend on one another for survival

• Show energy transfer among many feeding levels

Food Chains vs. Webs continues

EXAMPLE:GRASS (is eaten by a) GRASSHOPPER (which is eaten by) a FROG (which is eaten by a) SNAKE (which is eaten by a) HAWK

EXAMPLE:TREES produce acorns which act as food for many MICE and INSECTS. Because there are many MICE, the WEASELS, SNAKES, and RACOONS, have food. The insects in the acorns also attract BIRDS, SKUNKS, and OPOSSUMS. With the SKUNKS, OPPOSUMS, WEASELS and MICE around, HAWKS, FOXES, and OWLS can find food. They are all connected!

Terrestrial and Aquatic Relationship

Marine Environments

Marine Environments classified by:

-water depth and-ability of sunlight to

penetrate

Intertidal Zone location where ocean

meets the land-area is exposed for

part of the day organisms adapted to

exposure to air/survive crashing

waves

Neritic Zone along the continental shelf and

slope, temperature is warmEx: corals, sea turtles,fishes, and dolphins

Oceanic Zone floor dropssharply, deep water

Ex. fishes, whales, andsharks

Benthic Zone located at theocean floor. No sunlight

penetrates, extremely coldEx. fishes, worms and crabsOrganisms often live around

hydrothermal vents