Kingdom Animalia

Review Biology is the study of life… So what makes something living?

All living things must: Be made up of at least 1 cell that contains genetic material (DNA) Reproduce Grow (increase in size, mature, develop, etc.) Metabolize (have a need and use for energy) Respond to stimuli Maintain stable internal environment Change over time

That’s all fine and good, but when do we get to the animals? Zoology- the study of animals Two Major Categories: Vertebrates-have a backbone Invertebrates-do not have a backbone Vertebrate or Invertebrate?

Characteristics of Animals Multicellular Eukaryotes (cells with nucleus & organelles) Cells do not have a cell wall or chloroplast Ingestive heterotrophs (take in food and internally digest it) About 800,000 species have been identified of about an estimated 9 or 10 million that are estimated to inhabit the earth.

~ Characteristics ~ Have a nervous system to respond to their environment Locomotion relates to ability to obtain food Most animals develop from a zygote becoming a A single layer of cells surrounding a fluid-filled space forming a hollow ball of cells called a gastrula.

Locomotion: Motile-can move from one location to another on their own Sessile-cannot move from place to place, but do have moving parts Motile Sessile

~ Developmental Characteristics ~ The gastrula is made up of three parts: Ectoderm, a layer of cells on the outer surface of the gastrula, grows and divides developing into skin and nervous tissue. Endoderm, a layer of cells lining the inner surface of the gastrula, develops into the lining of the animal’s digestive tract. Mesoderm, made up of two layers of cells lying between the ectoderm and endoderm, forms muscles, reproductive organs and circulatory vessels.

~ Developmental Characteristics ~ Animals that develop a mouth from the indented space in the gastrula are protostomes. Animals that develop an anus from the opening in the gastrula are deuterostomes.

~ Body Plans ~ Animals that are irregular in shape are asymmetrical. Animals that are regular in shape are symmetrical.

~ Body Plans ~ An animal is asymmetrical if it cannot be divided into equal portions. An animal has radial symmetry if it can be divided along any plane, through a central axis, into equal halves. An animal has bilateral symmetry if it can be divided down its length into similar right and left halves forming mirror images of each other.

Which figure has bilateral symmetry? Which has radial symmetry?

Asymmetry The most primitive animals are asymmetrical Sponges are asymmetrical

Radial Symmetry Animals with radial symmetry are usually sessile, free-floating, or weakly swimming Like a wheel, animals with this spend most of their time floating like a bouy or attached to rocks They are different between their dorsal (back) and ventral (belly) surfaces

Bilateral Symmetry Most animal are bilateral they have an anterior (front) and posterior (rear) end Advantage: if a body part is damaged, the animal can rely on an identical part on its other side Being bilateral provides balance and aids in directional movement

Cephalization Bilateral symmetry has usually led to cephalization Cephalization is the process by which sensory organs and appendages become localized in the head end of animals

Evolutionary Trends If we analyze the basic body plans of animals, we find that they illustrate evolutionary trends: Multicellular body plan Radially symmetrical body plan Bilaterally symmetrical body plan “tube-within-a-tube” body plan Cephalization

Body Cavity Most animals have a body cavity, which is a fluid-filled space that lies between the digestive tract and the body wall. A body cavity is important because it provides a space in which internal organs can be suspended so that they are not pressed on by muscles or twisted out of shape by body movements. Body cavities also allow for specialized regions to develop, and they provide room for internal organs to grow and expand. In some animals, body cavities contain fluids that are involved in circulation, feeding and excretion.

~ Body Plans ~ Acoelomates – animals have three cell layers with a digestive tract but no body cavities. Pseudocoelomates – animals with a fluid-filled body cavity partly lined with mesoderm. Coelomates – animals with a body cavity completely surrounded by mesoderm.

~ Protection and Support ~ Though not all animals have a skeleton, those that do can be divided into two groups: Those with an exoskeleton – a hard, waxy coating on the outside of the body that protects internal organs, provides a framework for support, and a place for muscle attachment. A shell can also be an exoskeleton Those with an endoskeleton – support framework within the body that protects some organs and a brace for muscles to pull against. They are usually made of cartiladge and/or bone

What Animals Do to Survive All animals survive and respond to the environment in different ways Animals carry out the following essential functions: feeding, respiration, circulation, excretion, response, movement, and reproduction.

Feeding Animals have evolved a variety of ways to feed. Herbivores are animals that eat plants, including roots, stems, leaves, flowers and fruits. Carnivores feed on other animals. Filter feeders are aquatic animals that strain tiny floating plants and animals from the water around them. Detrivores are animals that feed on pieces of decaying plant and animal material called detritus. Animals can also form symbiotic relationships, in which two species come in close association with each other.

Respiration Whether they live in water or on land, all animals respire. They take in oxygen and give off carbon dioxide. Because of their very simple, thin-walled bodies some animals can rely on the diffusion of these substances through their skin. Most have evolved complex tissues and organ systems for respiration.

Circulation Many small aquatic animals rely solely on diffusion to transport oxygen, nutrients, and waste products among all their cells. Diffusion Larger animals, however, have some kind of circulatory system to move materials around within their bodies.

Excretion Primary waste product= ammonia A build up of it can kill an animal. This makes excretion essential to life. Excretory system eliminates ammonia quickly or converts it into a less toxic substance that is removed from the body. These vary from group of cells that pump water out of the body to complex organs such as kidneys.

Response Animals respond to events in their environment using specialized cells called nerve cells. In most animals, nerve cells hook up together to form the nervous system. Some cells, called receptors, respond to sound, light, and other stimuli. The arrangement of nerve cells in the body changes dramatically from phylum to phylum.

Movement Some animals live their entire adult lives attached to a single spot. Most animals, however, are motile. Others use muscles and a muscle contractions to move around. Also use a skeleton.

Reproduction Most reproduce sexually by producing haploid gametes. Helps create and maintain genetic diversity in populations. Helps improve species’ abilities to evolve when the environment changes. Many animals, especially invertebrates, can reproduce asexually. Allows animals to increase numbers rapidly.

~Invertebrates~ 8 main phyla No backbones 95% of all animals are in this group

~ Phylum Chordata ~ subphylum Vertebrata 5 classes Fish Mammals Reptiles Amphibians Birds

Animal Taxa