Summary
Multicellular heterotrophic eukaryotes without cell walls that typically move and ingest food.
In depth
Animals are multicellular heterotrophs with cells lacking walls, extracellular matrix with collagen, nerve and muscle cells (except sponges), and typically sexual reproduction with a distinctive embryonic development. Around 1.5 million species are described; the real number may be several million.
Animals evolved from colonial choanoflagellate-like ancestors.
Animals are grouped into about 35 phyla. Body plans differ in symmetry, germ layers, cavities and development. Evolution from simple to complex is not linear.
Key idea: animals share heterotrophy and multicellularity.
Frequently asked questions
What is Animal Kingdom?
Multicellular heterotrophic eukaryotes without cell walls that typically move and ingest food.
Which area of biology covers Animal Kingdom, and how advanced is it?
Animal Kingdom is one of the 53 topics in Zoology & Animal Diversity. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Body Cavities, Sponges, Insects.
Can you give an example of Animal Kingdom?
Most animals are insects.
What should I learn before Animal Kingdom?
Animal Kingdom is a Beginner topic, so no earlier topic is required. Other Beginner topics in Zoology & Animal Diversity that pair well with it include Vertebrates and Invertebrates, Sponges, Cnidarians.
What topics are related to Animal Kingdom?
The closest topics to Animal Kingdom are Body Cavities, Sponges, Insects, Animal Symmetry. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Animal Kingdom?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Animal Kingdom. To practise the whole of Zoology & Animal Diversity, use the Zoology & Animal Diversity quiz.
How is Animal Kingdom different from Body Cavities?
Animal Kingdom: Multicellular heterotrophic eukaryotes without cell walls that typically move and ingest food. Body Cavities: Acoelomate, pseudocoelomate and coelomate animals differ in how the fluid-filled cavity around organs is formed. Read both side by side and note what each one explains.
How should I study Animal Kingdom step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Body Cavities and explain the difference aloud. Finally, take the Zoology & Animal Diversity quiz and come back to this page for any question you miss.