The animal kingdom is extremely diverse, with some animals being microscopic while others are several meters long, living in various environments from inside other bodies to the open sea. Animals are multicellular eukaryotes that lack cell walls and carry out essential functions like feeding, respiration, circulation, excretion, response, movement, and reproduction to maintain homeostasis. The kingdom is divided into invertebrates, which lack backbones, and vertebrates, which have backbones.
2. Introduction to the Animal Kingdom The Animal Kingdom is the most diverse in appearance. Some animals are so small that they can live inside other animals. Others are many meters long and live in the sea, they can walk, swim, crawl, burrow , fly, or not move at all. Each major group, or phylum, has its own typical body plan.
3. What is an Animal? Animals, members of the Kingdom Animalia, are multicellular, eukaryotic heterotrophs whose cells lack cell walls.
4. Invertebrates- are animals that do not have a back bone. Vertebrates- are animals with back bones Invertebrates and vertebrates
5. What Animals Do to Survive Animals carry out the following essential functions: feeding, respiration, circulation, excretion, response, movement, and reproduction. Many body functions help animals maintain homeostasis, or a relatively stable internal environment. Feedback inhibition helps animals release heat.
