Slide 1 We now begin our discussion of Kingdom Animalia. The animal kingdom is very diverse and includes both organisms that are very familiar to most of us and some not so familiar organisms.
Slide 2 Fossil evidence suggests that animals evolved about 700 million years ago. They most likely evolved from a colonial protist similar to present day choanoflagellates. Choanoflagellates are similar in morphology and composition to the choanocyte cells of sponges - the first group of animals to evolve.
Slide 3 Animals are all multicellular and many individuals in the kingdom are known for their advanced mobility - like this lynx and hare shown here. All animals are also ingestive heterotrophs (remember, this is in comparison to the fungi which are absorptive heterotrophs). The animals are also marked by having well-developed tissues and a nervous system. We will see that these last two characteristics do not apply to the sponges.
Slide 4 Tissues are collections of cells that perform the same function. They are not unique to the animals but many animals have highly developed and highly specialized tissues. An example is muscle tissue. Muscles are contractile tissues comprised of cells that are specialized to produce a force that allows movement. Muscle tissues have allowed many animals to develop amazing mobility including running, jumping, swimming and flying.
Slide 5 Nervous tissue is tissue that is specialized to coordinate the transfer of information from the environment to the organism and around the organism. Many animals have both a central nervous system (which is essentially a brain) and a peripheral nervous system which is comprised of sensory cells that send information to the brain. The nervous system is made up of specialized cells called neurons - these are cells that send signals. The functions of the nervous system are sensory input, integration of sensory information, control of muscles and glands, maintenance of homeostasis within an organism, and mental activity. Nervous tissue is unique to Kingdom Animalia and some animals have highly developed nervous systems.