7th Grade Science 052918 Mr. Hankins

Review Aquatic Ecosystems:

Two types of Aquatic Ecosystems:
1. Freshwater Ecosystems
2. Marine Ecosystems
Freshwater Ecosystems:

• Most of the earth is covered with water, however, only a small portion is freshwater.
  
• Freshwater ecosystems include:
  

1. Streams
   
2. Rivers
   
3. Ponds
   
4. Lakes
   

• Streams & Rivers:
  
  • Streams begin with cold and clear water flowing rapidly.
    
  • Animals that live here are adapted to the strong current, insects and small animals have hooks and suckers that cling them to rocks.
    
  • Trout have streamlined bodies that allow them to swim in rapid moving water.
    
  • Not many producers can grow in the fast current, therefore first level consumers feed off of leaves and seeds that fall into the streams.
    
  • Rivers are formed from many streams feeding into one body of water.
    
  • Rivers are slower moving and warmer.
    
  • Plants take root in the pebbles at the bottom, which provide food for insects and homes for frog and other animals.
    
  • These consumers provide food for many larger consumers.
    

• Ponds & Lakes:
  
  • Ponds and lakes are bodies of standing, or still, fresh water.
    
  • Lakes are generally larger than ponds.
    
  • Ponds are shallow enough for sunlight to reach the bottom and allow plants to grow.
    
  • Organisms include insects, turtles, frogs, snails, toads, and fish.
    
  • Scavengers like catfish live near the bottom.
    
  • Bacteria and other decomposers feed on the remains of other organisms.
    
  • Lakes contain algae as their major producers.
    

• Marine Ecosystems: Marine (of or relating to the sea or the plants and animals that live in the sea)
  
  • 4 types of marine ecosystems
    

1. Estuary
   
2. Intertidal Zone
   
3. Neritic Zone
   
4. The Open Ocean
   

• Estuary:
  
  • where the freshwater of a river meets the salt water of the ocean.
    
  • Many animals use the calm waters or estuaries for breeding grounds.
    
• Intertidal Zone
  
  • Between the highest tide line and the lowest tide line
    
  • Tide (the regular upward and downward movement of the level of the ocean that is caused by the pull of the sun and the moon on the earth)
    
  • Organisms must be able to withstand pounding waves and sudden changes in water levels and temperature due to high and low tides.
    
  • Animals such as barnacles and sea stars cling to rocks. Clams and crabs burrow in the sand.
    
• Neritic Zone
  
  • The edge of the continent extends into the ocean for a short distance creating a continental shelf.
    
  • The neritic zone is a region of shallow water that extends over the continental shelf.
    
  • Sunlight passes through the shallow water which allow photosynthesis to occur to grow many producers such as algae and coral reefs.
    
  • The producers provide food for a zone rich in living things.
    
• The Open Ocean
  
  • The surface zone, light penetrates only a few hundred which allows algae to grow on the surface - to feed many marine animals.
    
  • The deep zone is almost totally dark.
    
  • Most animals in the deep zone feed on the remains on organisms that sink down from the surface zone.
    
  • The deepest parts are home to a variety of very weird alien like looking creatures whose eyes glow in the dark.