Hello, Bea here and welcome back to biology! Today we will be starting a new unit focusing on the
Animal Kingdom. Through the next seven lessons you will learn about a wide exciting range of animals
from those you are familiar with to those that you may have never seen before including animals that
don't even look like animals like some of these fun unique and interesting organisms! But before
we get started, let's look at our goals for this lesson. By the end you'll be able to identify the
key characteristics that define animals, explain how animals differ from the living organisms in
the other kingdoms, identify the main categories of animals, and provide an example of each.
The animal kingdom is the largest of all of the kingdoms with over 9 million species! Can
you think of some of the key characteristics that scientists use to identify organisms as animals?
When determining if an organism is an animal, scientists use five main characteristics. 1.
Animals are multicellular heterotrophic organisms. Do you remember what it means for an organism
to be heterotrophic? It means that the organism receives its nourishment by consuming other living
organisms. Okay, back to our list. 2. Animals typically reproduce via sexual reproduction.
3. Animal cells do not have cell walls. 4. Animals have an internal digestive system. And finally,
5. Animals have the ability to move. Even if you don't see them moving they do move.
Sponges move across the sea floor at a rate of a few millimeters a day!
We mentioned earlier that the kingdom Animalia is the largest Kingdom of organisms. Scientists
aren't in complete agreement on the number of phyla that make up the kingdom,
but we do know that there are over 35 of them. This is compared to only four
in Kingdom plantae and five in kingdom fungi. In this unit we will be focusing on six main
groups of animals that encompass all of the phyla: invertebrates, fish, birds, reptiles,
amphibians, and mammals. Let's spend a little time talking about each group.
First up, invertebrates! Invertebrates are animals that do not have a backbone. They also have a
simple nervous system and a soft body. The next group is fishes. Fishes are aquatic vertebrates
meaning they live in the water and have a backbone, are cold-blooded so they are unable
to control their body temperature, and have fins and a streamlined body shape that helps them swim.
Our third group are birds. Birds along with the rest of our groups are vertebrates, have feathers,
and beaks, have the ability to fly, only two legs, lay eggs, and are warm blooded meaning they
can control their own body temperature. Reptiles are next on our list. Reptiles are cold-blooded,
have scaly skin, external ears, and lay eggs. Next up amphibians. They are also cold-blooded
and lay eggs, but have four legs, external gills, and moist permeable skin. Finally,
we have mammals. Mammals are warm-blooded, have fur or hair, reproduce via internal fertilization
meaning they give birth to live young, and have mammary glands to produce milk for their young.
As you can see there is a lot of overlap in these groups but each is distinct in their own right.
Scientists use these distinctions to identify and classify animals.
As we went through the lesson today we looked at the wide variety of organisms that make up the
animal kingdom. We saw how they range from the simple sponges, to the aquatic fishes,
to complex mammals. We also looked at the defining characteristics of the kingdom and
the six main groups of animals. As we go through the unit, be sure to fill out the lesson notes in
the PDF and complete the other activities found there. You will need the information in the PDF
to successfully complete the lesson assessment. As always the PDF pages for the entire unit are
attached to this lesson and you'll also find the PDFs for each individual lesson after each video.
As we move through this unit we will go into more depth on each of these
groups and also look at how they have adapted to survive in their
environments. We will spend our first two lessons learning more about invertebrates.
Until then remember that biology isn't just science, it's the way of life! See you next time!