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Interested To Register And Sign Up For Marine Biology Course?

Course Description

Marine biology is the science of saltwater and everything that lives, moves, and filters through it. The word "marine" in this sense refers specifically to saltwater that you find in oceans, not freshwater, which is found in lakes.

When you look at a globe, you can see that nearly three quarters of the Earth's surface is covered with water. Scientists believe life on Earth got its start in the ocean, and gradually adapted to life on land. Some land-based organisms eventually returned to the water, like dolphins and whales. Tiny ocean plants, called phytoplankton, produce most of the oxygen in the air we breathe. When producing oxygen, these plants soak up carbon dioxide, removing this gas from the air.

The ocean is always in motion: currents move water around the globe. Water evaporates and rises into the atmosphere where it will eventually fall as rain and snow. Cold water sinks in the ocean, warm water rises, and this constant movement distributes heat and nutrients around the globe.

In this course, you will learn about life in the ocean depths, at the Polar extremes, in coral reefs, estuaries, and in the open sea. You will learn about plants large and small, marine birds, reptiles, invertebrates and fish. You will learn how all these organisms connect with each other in the marine biome, and what threats are facing these ecosystems.

The Ocean Environment

Over millions of years, water running off the land dissolved salt from rocks and carried it downstream into the ocean. Salt also poured out of volcanic vents deep under the ocean. The sun and heat went to work and evaporated the water into the atmosphere, and the salt stayed behind in the sea. Today, the average salt level, or salinity, in the ocean is 35 parts per thousand, or ppt. Some oceans, like the Black Sea, are less salty and some, like the Dead Sea, are even more salty than average. The higher the salinity of the water, the denser the water is (higher density or specific gravity). In the Dead Sea, the water is so salty and dense that people can float on top of the water effortlessly, like a cork. 

Not all organisms can live in a high salinity environment. People, for example, can't survive in saltwater. Since you have no special adaptations to remove salt, if you drink too much seawater, your kidneys will try to flush the excess salt out as quickly as possible through urine, and you would lose more water than you originally drank, leaving you dehydrated. If you didn't correct the situation by replacing fluids with fresh (non salty) water, your organs would eventually shut down and you would die. 

Living in the ocean requires special adaptations, like a tolerance for salt or a way to remove the excess effectively, the ability to move through the water, find food, hide from predators, and locate a mate.  

On land, we tend to think that ecosystems develop in certain geographical areas, but in the ocean, distance doesn't matter as much as depth. The ocean environment changes as you move deeper into the water. It becomes colder and darker. The pressure is higher and there is less oxygen dissolved in the water. The living conditions are so different at different depths that plants, bacteria and animals can usually only live in certain zones. Scientists call this vertical stratification.

Science and Marine BiologyScientists generally agree that all life, from algae to whales, all descended from the same original ancestor. This one ancestor reproduced, and its offspring reproduced.  

According to the theory of evolution, as generations passed, the descendants changed, or evolved, until they did not resemble one another at all. Once these distant relatives weren't able to reproduce with one another, they became entirely different species. Scientists study all the different organisms existing today and analyze the traits that they have in common to group them into families. Although scientists argue about how evolution happens and how long the process takes, they do agree that change is constant and that it's going on right now. Species which did not change, or adapt, to changing circumstances eventually died out and became extinct. 

An adaptation is a successful change that provides an organism with an advantage for living in its environment. The theory of evolution argues that organisms that are best adapted to their environment have the best chance of surviving long enough to reproduce. When organisms don't have to work as hard to get food or fight predators, they have more energy for reproduction, which means they can have more offspring. Over time, the descendants of well adapted organisms will increase and multiply while less successfully adapted organisms spend more time just trying to survive, and will eventually die out. This process is called natural selection.

What is Ecology?Ecology is the study of relationships between living organisms and their environment. Instead of looking specifically at one type of plant or fish, ecologists look at the big picture. For example, if one type of fish usually eats a lot of algae, but the fish suddenly disappears from its ecosystem, the algae might grow out of control. It could cloud the water and keep the plants below from being able to use the sun for energy. Lower plants might die off, and other fish that used the plants for food and shelter would suffer.

Understanding the relationships between species has helped scientists derive useful medicines from natural sources, like a substance in horseshoe crabs that is now used in leukemia treatments. 
 

Lesson 1 : Introduction

Marine biology is the science of saltwater and everything that lives, moves, and filters through it. 40 Total Points 

  •  Video
  •  Review Article: Becoming a Marine Biologist
  •  Take Poll: Marine Biology
  •  Take Survey: Reasons for Taking this Course

 Complete Assignment: An Introduction

  •  Complete: Lesson 1 Assignment
  •  Complete Exam: Lesson 1: Introduction

Lesson 2: Geology and the Ocean

The area where old crust is sinking under another slab of crust is called a subduction zone. Subduction zones create such deep trenches that they are all below sea level. 35 Total Points 

  •  Lesson 2 Video
  •  Review Article: Marine Geology
  •  
  •  Complete: Lesson 2 Assignment
  •  Complete Exam: Lesson 2: Geology and the Ocean

Lesson 3: Currents and Tides

The term current refers to the motion of water. On land, the motion of water is usually driven by gravity: rain falls from clouds and then runs downhill toward lakes and to the ocean. 35 Total Points 

  • Lesson 3 Video
  •  Review 2 Articles: Tides and Currents; Waves, Tides and Currents
  •  Complete: Lesson 3 Assignment
  •  Complete Exam: Lesson 3: Currents and Tides

Lesson 4: What's in a Name?

A species is a group of organisms that are able to successfully reproduce with one another. 35 Total Points 

  • Lesson 4 Video

  •  Review 2 Articles: Marine Taxonomy; The Classification of Living Things
  •  Complete: Lesson 4 Assignment

  •  Complete Exam: Lesson 4: What's in a Name?

Lesson 5: Invertebrates

The jellyfish, for example, contracts its umbrella shaped body to propel itself through water. Other invertebrates use water pressure, shell, or cups to support themselves. 35 Total Points 

  • Lesson 5 Video

  •  Review 2 Articles: Marine Invertebrates; The 31 Types of Invertebrates

  •  Complete: Lesson 5 Assignment
  •  Complete Exam: Lesson 5: Invertebrates

Lesson 6: Vertebrates

There are seven main classes and superclasses of vertebrates that include fish, reptiles, amphibians, birds and mammals. 35 Total Points 

  • Lesson 6 Video
  •  Complete: Lesson 6 Assignment
  •  Complete Exam: Lesson 6: Vertebrates

Lesson 7: Marine Fish

The study of fish is called ichthyology, and ichthyologists have grouped all fish into three main categories: jawless, cartilaginous, and bony. 35 Total Points 

Video
Review 2 Articles: 20 Weirdest Fish in the Ocean; Marine Fish Species

Complete: Lesson 7 Assignment
Complete Exam: Lesson 7: Marine Fishes

Lesson 8: Marine Mammals

Mammals, whether they live on the land or in the sea, are all vertebrates (meaning they have a backbone and a brain). 35 Total Points 

Video
Review Article: List of Marine Mammals

 Complete: Lesson 8 Assignment
 Complete Exam: Lesson 8: Marine Mammals

Lesson 9: Marine Ecosystems

A biome is a large geographical area that contains several different ecosystems. All the plants, animals and other organisms that live in a biome are adapted to that environment. 35 Total Points 

  •  Video
  •  Complete: Lesson 9 Assignment
  •  Complete Exam: Lesson 9: Marine Ecosystems

Lesson 10: Life at the Shore

The intertidal zone (also called the foreshore, seashore and the littoral zone) is the area that is exposed to air at low tide and underwater at high tide. 34 Total Points 

  •  Video
  •  Review 2 Articles: The Intertidal Zone; Tide Pools
  •  Take Poll: Tide Pools

  •  Complete: Lesson 10 Assignment
  •  Complete Exam: Lesson 10: Life at the Shore

Lesson 11: Estuaries

An estuary is one type of intertidal zone, where a river meets the sea: freshwater meets saltwater in a bay, lagoon, sound, or slough. 35 Total Points 

  • Video
  •  Review 2 Articles: Estuaries; Exploring Estuaries

  •  Complete: Lesson 11 Assignment
  •  Complete Exam: Lesson 11: Estuaries

Lesson 12: Coral Reef Biology

Coral reefs are usually found in the tropics, and although corals make up a big part of the reef, they are just one component of an enormous community. 35 Total Points 

  • Video
  •  Review Article: Coral Reef Biology
  •  
  •  Complete: Lesson 12 Assignment
  •  Complete Exam: Lesson 12: Coral Reef Biology

Lesson 13: Coral Reef Ecosystems

Many marine scientists think that most reefs start out as fringe reefs, and over time, the coral grows out and away from land. As it gets farther from land, the reef's diameter expands and a large lagoon forms. 35 Total Points 

  •  Review Article: Coral Reef Ecosystems
  •  Complete: Lesson 13 Assignment
  •  Complete Exam: Lesson 13: Coral Reef Ecosystems

Lesson 14: Life in the Polar Oceans

Although the two poles have a lot of similarities, like very cold weather and extreme living conditions, life in the two regions was shaped by a different series of circumstances. 35 Total Points 

  • Video
  •  Review 2 Articles: Arctic Ecosystem; Polar Oceans
  •  Complete: Lesson 14 Assignment
  •  Complete Exam: Lesson 14: Life in the Polar Oceans

Lesson 15: The Open Sea

The open ocean is the largest biome in the world by volume, but in terms of the quantity of life, the Pelagic resembles the most enormous desert ever known. 35 Total Points 

  •  Video
  •  Review 2 Articles: Pelagic Biome; The Open Ocean
  •  Complete: Lesson 15 Assignment
  •  Complete Exam: Lesson 15: The Open Sea

Lesson 16: Life in the Ocean's Depth

The Benthic Zonerefers to the sea floor, which extends from the tidal areas all the way down to the deepest trenches on the planet. 35 Total Points 

  • Video
  •  Review 2 Articles: The Deep Ocean; The Deep Sea Biome
  •  Take Poll: Marine Organisms
  •  Complete: Lesson 16 Assignment
  •  Complete Exam: Lesson 16: Life in the Ocean's Depth

Lesson 17: Oceans in Jeopardy

Some of the major threats facing the oceans include climate change, pollution, nutrient runoff, garbage dumping, overfishing, and ship strikes. 110 Total Points 

  •  Video
  •  Review 2 Articles: 7 Biggest Problems Facing Oceans; The Ocean's Problems
  •  Take Poll: Ocean Challenges
  •  Take Survey: Program Evaluation Follow-up Survey (End of Course

  •  Complete: Lesson 17 Assignment
  •  Complete Exam: Lesson 17: Oceans in Jeopardy

 Complete: The Final Exam

Total Course Points : 674

Learning Outcomes

By successfully completing this course, students will be able to:

  • Define what marine biology is and why it is important to study.
  • Describe geology and the ocean, currents and tides.
  • Understanding the nomenclature of marine biology
  • Identify invertebrates of the marine environment.
  • Identify vertebrates of the marine environment.
  • Identify marine fish.
  • Identify marine mammals.
  • Describe marine ecosystems.
  • Summarize what estuaries are and why they are important.
  • Summarize coral reef biology and ecosystems.
  • Describe life in the polar oceans and the open sea.
  • Describe life in the ocean's depth and its future with the human race, and
  • Demonstrate mastery of lesson content at levels of 70% or higher.
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