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Animal Evolution and Diversity
Animal Evolution and Diversity
Topics in Depth
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Table of Contents
Animal Evolution and Diversity Topics in Depth
What is an Animal?
We know one when we see one. A dog is an animal. We are animals. What about a sponge? Sponges are animals, too. That's right—we mean SpongeBob.All life is divided into six kingdoms: BacteriaArcha...
Life on Earth did not start out with animals. All life on earth started from the primordial ooze where inorganic molecules produced organic molecules, organic molecules formed bigger molecules, and...
The Animal Family Tree
We are family. All animals are related, but figuring out the relationships is not straightforward. Traditionally, the family tree has been based on body plan and how embryos develop. Animals with c...
Let the Food Come to Them
It's alive! Sponges are animals, the oldest ones around. The first branching in the animal family tree is the split between the parazoa and eumetazoa. The difference between these two groups of ani...
Polyps and Medusas
Muscles and Nervous Systems and Organs, Oh MyThis is the beginning of the rest of the animal kingdom, the eumetazoa or "true animals" (we eumetazoans are a little biased). Eumetazoans have tissues...
These animals definitely have a front end and they point it in the direction they are moving. From here on out, the animal body plan is bilaterally symmetrical. The remaining animals in the animal...
Invertebrates Get More Complex
The rest of the animal phyla fits into the next two big branches of the animal family tree: the protostomes and the deuterostomes. In this section we'll cover one of the three protostome phyla: Mol...
What's In a Worm?
Segmented worms like earthworms and leeches are found all over the place—from our compost to under the sea. Annelida means "little rings," which is how these worms look on the outside, like the b...
Life Takes to the Land
We see arthropods everywhere we go. Arthropoda, the third protostome phylum, is everywhere. Arthropods live on the land and in the sea. They swim, run, and fly. Arthropods mean a lot to us, too. W...
Relationships are hard. Four invertebrate phyla remain to be discussed and they are tricky. The phyla Phoronida, Bryozoaand Brachiopoda used to be grouped together into one group called lophophores...
Get a Backbone
When we think "animal," this is usually where our mind goes. We'll first look at what a chordate is and then the earliest vertebrates, the fish.We are members of this phylum, Chordata. What do we h...
Nothing Like a Place at the Beach
Vertebrates Take to the Beach First it's the ancestors of frogs and salamanders that crawl from the deep blue sea. Then, for a while, dinosaurs rule the earth. AmphibiansWeather has always be...
If there is space, someone will move in. With flying dinosaurs going away, airspace opened for birds. Flight takes a lot of energy, but it offers access to flying insects and the ability to see foo...
Cute and Furry
Mammals evolved from reptile ancestors, just like birds. Mammals, however, came first and they came from a different reptilian stock: therapsids, descendants of the synapsids. Small mammal ancestor...
You will appreciate your thumb so much more after this.We are primates, as are monkeys, apes, and those cute little lemurs in Madagascar. Primates are one of the newer orders of eutherian mammals....
What is an Animal? When we think of life, we generally remember plants and animals. Try a mnemonic to get them all:All Boy Pilots Fly Paper Airplanes (Archaea, Bacteria, Protista, Fungi, Plantae, A...
Test Your Knowledge
What is an Animal? 1. The six kingdoms of life are:2. Animals are: a. Prokaryoticb. Heterotrophicc. Haploidd. a. and b.e. b. and c.3. What unique tissues are characteristic of animals:4....
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