Hello, I'm Ashley, and today we're going to learn about animal classification.
In this video, you will learn how scientists identify what groups of animals belong to and
the characteristics of each classification group. You will also learn about how scientists classify
groups of living things through taxonomies. Do you know how living things are grouped? What makes
something an animal? How do scientists determine whether an animal is a reptile or a mammal?
Well, scientists use a classification system to categorize living things.
This way of classifying things is called a taxonomy. Taxonomies are often shown as a tree
having many branches or an inverted pyramid that becomes more specific as you go on.
The taxonomy for living things has five levels to it, from most general to most specific. We'll
start learning with kingdom, then phylum, class, order, family, genus, and finally species. There
is also a broader level called a domain, but it is usually only used in higher levels of science.
For the purpose of this video, we're going to stick to the main five. Let's take a look at what
each of these levels means more specifically and how living things are grouped into them.
A kingdom is the broadest classification for eukaryotic life on Earth.
There are five recognized kingdoms today: animals (which we will discuss further in this video),
along with plants, fungi, protists, and monera.
After kingdom, we have phylum. Phyla groups specimens in a kingdom based on common
characteristics. Animals are grouped into a phylum based on whether or not they have a backbone.
First, there's vertebrates, such as foxes, dogs, humans, and most life on Earth
that all have a backbone. Then there are invertebrates, such as jellyfish,
that don't have a backbone or bone structure in their body.
Classes are the next level on the taxonomy after phyla. Invertebrates don't have specific classes;
however, there are six vertebrate classes: mammals, reptiles, amphibians, fish, birds,
and arthropods. Later in this video, we will delve deeper into the six vertebrate animal classes.
For now, we are going to review what classification might look like for a specific species or animal.
To do this, we will look at a cat more specifically. After "class," the remaining
taxonomy levels become increasingly specific, and in some cases, scientists still debate where to
put animals in relation to each other for genus and species. Cats are part of the animal kingdom.
They are classified under the phylum Chordata, meaning they have a backbone with a tail.
In terms of cats, they give birth to and nurse their young, they have hair on their body,
and are warm-blooded and breathe through their lungs. This places them in the mammal class. Don't
worry if you're not familiar with this class yet; we'll get into that later in the video.
After mammals, cats are sorted based on other qualities, such as what they eat (cats' order is
Carnivora) and what other species they resemble and the fact that they are domesticated.
Thus, we can see how taxonomies give specific information for traits of the animals
because it groups them by traits. Taxonomies also give many species their scientific names.
Scientific names are useful because, in addition to giving
information about what groups they belong to and their traits, scientific names avoid confusion.
The common name of a species that you or I might use can vary based upon region.
A good example of this is how mountain lions can also be called cougars, panthers,
catamounts, and pumas depending on the location. However, knowing their scientific name,
Puma concolor, ensures that scientists are on the same page when discussing them.
Now that we have discussed taxonomies and their use, let's take a closer look at animal classes.
Mammals, one type of animal class, are identified by scientists through a number of traits. Mammals
give birth to and nurse their young, have hair either on sections or covering their entire body,
are warm-blooded, and breathe through lungs.
Examples of mammals that you might know include tigers, squirrels, whales, and humans.
Another animal class is reptile. Reptiles lay eggs with leathery shells,
they have scales, are cold-blooded, and breathe with lungs.
Examples of reptiles that you might know include snakes, lizards, crocodiles, and turtles.
Amphibians are a class of animal that lay eggs in a jelly-like mass in the water,
have smooth skin without coverings, such as feathers, hair, or scales, and
are cold-blooded. Amphibians are unique in that they are able to breathe through gills, lungs,
and/or their skin, depending on their stage of life and what species they are. Amphibians also
hatch in the water and live in water for the first part of their life
but change to become land-dwelling for the second part of their lifespan.
Fish are a class of animal that lay eggs in the water.
Unlike amphibians, fish eggs don't commonly have a jelly-like substance surrounding them. Also,
unlike amphibians, fish live in the water for their whole lifespans. Fish have smooth, leathery
skin or, more commonly, scales. Fish breathe through gills and have fins that propel them through the
water instead of arms or legs. However, not all animals with fins are fish. Dolphins and whales,
which give birth to their young and are warm-blooded, are not fish but mammals.
Another animal class is birds. Birds lay eggs with a hollow shell
and live on land. Birds are warm-blooded, have feathers as coverings, and have beaks.
Birds have hollow bones, which help them to be more aerodynamic. Birds also have wings
and two legs. Though all birds have wings, not all birds can fly, and several types of birds,
such as ostriches and penguins, don't have the ability to fly. In addition, flying is
not unique to birds. Other types of animals, such as some mammals and arthropods, can fly.
The final animal class we will discuss is
arthropods. Arthropods are animals that have more than four limbs.
Arthropods also commonly have paired, jointed limbs, a segmented body, and an exoskeleton.
Arthropods are a broad class that includes many different species, including crabs and insects.
Do you know what differentiates a reptile and an amphibian? What about a fish and a mammal?
Do you know the order of classifications from kingdom to species? Try researching
the classification of your favorite animal online or at the library.
Be sure to practice what you've learned, and remember to always be clever.