All / Kingdom: Animalia

Q: What are animals, and how do we define them?

How we do define animals? Why cant animals be insects, or insects be animals?


A:

Let’s start with how we define animals:

It is estimated that around 9 or 10 million species of animals inhabit the earth; the exact number is not known and all estimates are rough.

All animals are members of the Kingdom Animalia, also called Metazoa.

All members of this Kingdom are multicellular, and all are heterotrophs (they rely directly or indirectly on other organisms for their nourishment). Most ingest food and digest it in an internal cavity.

The kingdom of Animalia does not contain prokaryotes (organisms made up of cell Membersls that lack a cell nucleus or any membrane-encased organelles). Examples of prokaryotes are bacteria and blue-green algae. It also does not contain orprotists (Kingdom Protista, which includes unicellular eukaryotic organisms)

SixKingdomsBiology_DV_big

Animals range in size from no more than a few cells to massive organisms weighing many tons. They include vertebrates–animals such as ourselves, and other mammals we often associate with the animal kingdom


 

Which leads us to part 2 of your question:

By far most species of animals on this planet are, in fact, insects! (as well as a diverse number of mollusks, crustaceans, and nematodes).

Insects are part of a bigger animal group called arthropods. The word Arthropod literally means jointed limbs.

d5df1ff24c898d8d65f2c9f1a9f41bd6

Our own group, the vertebrates, are relatively inconsequential from a population and diversity perspective. So not only are insects, in fact, animals–they are the most prevalent and diverse animals on planet Earth!

 

 

 

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s