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Organisms

Organisms

Description:

This lesson will introduce the characteristics of living things such as the basic characteristics of life and how living things are structured and classified.

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Tutorial

What's Covered

Welcome to this lesson on organisms and their characteristics, classifications, structural organization. Today you will learn all about:

  1. Characteristics of All Organisms
  2. Structural Organization of Organisms
  3. How Scientists Classify Organisms

1. Characteristics of All Organisms

Organisms are living things; they can be anything from a small unicellular organism to an elephant, a human, or a plant. Anything that's alive and living is an organism. The following are five characteristics that all living things have in common:

  1. All living things use energy.
  2. All living things will respond to their environment.
  3. All living things are composed of cells. Cells are the basic units of all life. To be alive, something has to be made up of cells.
  4. All living things will be able to maintain homeostasis, which means they can maintain their internal environment.
  5. All living things are able to grow and reproduce.

Terms to Know

Cell

A cell is the basic unit of life.

Homeostasis

Homeostasis is an organisms ability to maintain a constant internal environment.


2. Structural Organization of Organisms

The way living things are structured is from very, very small to large. All living things are made up of atoms, and these atoms compose molecules.

IN CONTEXT

You know that the human body is made up of a lot of water, and water is made up of hydrogen and oxygen. So you're made up of atoms, which compose molecules; those molecules then compose cells. Some living things are only made up of one cell.

For complex organisms like humans, you continue farther down the line. Our cells will make up tissues, and those tissues will make up organs. Then those organs can make up organ systems. Finally, the organ systems will make up the entire organism.

Example All of your organ systems, such as your digestive system, your nervous system, your lymphatic system, et cetera, work together to make up the full organism that is yourself.

To summarize, atoms make up molecules, which make up cells, which make up tissues, which make up organs, which make up organ systems, which make up an entire organism.

The image below can be used to visually understand the process.


3. How Scientists Classify Organisms

Scientists like to classify organisms into different groups based on characteristics they have in common. Every living thing is classified by scientists into kingdom, phylum, class, order, family, genus, and species.

To better understand, take a look at the classification of a panda bear.

You'll notice the inverted triangle. As you move down these groups, they're getting smaller and smaller and smaller. If you think of every living thing in the entire world, it fits into one of five groups, so these groups are actually very, very large. But as you move all the way down to species, it becomes very specific where only one organism fits into each type of species. So you’re getting more specific as you move down the classification.

KINGDOM: Kingdom is the first classification. All living things can be classified into one of five kingdoms:

  1. Monera
  2. Protista
  3. Fungi
  4. Plantae
  5. Animalia

PHYLUM: Our next level of classification is the phylum. Within the kingdom Animalia, there are actually about 30 different phyla. The phylum for panda bear is a Chordata; this means that it's a vertebrate, or it has a backbone. Humans have a backbone and thus fit into the same kingdom and phylum as a panda bear. A clam does not have a backbone, so it would be considered an invertebrate and belong to a different phylum, but would still be in the same kingdom as a panda bear because it's still an animal.

Terms to Know

Vertebrate

A vertebrate is an organism that has a backbone.

Invertebrate

An invertebrate is an organism that does not have a backbone.

CLASS: The panda’s class is Mammalia, which tells you it's a mammal. All mammals share certain characteristics. Humans are also considered mammals, so humans are in the same kingdom, phylum, and class as a panda bear.

ORDER: The order for a panda bear is Carnivora because it is a carnivore; it eats meat.

FAMILY: A panda’s family is Ursidae; that family is a family of bears. Humans do not share this characteristic in common with the panda bear.

GENUS & SPECIES: This is when you hear the scientific name of an animal. The scientific name is its genus and species together. The species is specific only to the panda bear; no other animal in the world is the same species as a panda bear.


Summary

This lesson has been an overview on the characteristics of all organisms, such as energy and cells, the structural organization of organisms, and how scientists classify organisms.

Keep up the learning and have a great day!

Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND

Terms to Know
Cell

A cell is the basic unit of life.

Homeostasis

Homeostasis is an organisms ability to maintain a constant internal environment.

Invertebrate

An invertebrate is an organism that does not have a backbone.

Vertebrate

A vertebrate is an organism that has a backbone.