KINGDOM ANIMALIA General Characteristics of Animals Kingdom Animalia

KINGDOM ANIMALIA General Characteristics of Animals

Kingdom Animalia All animals are multicellular, eukaryotic heterotrophs Adult animals develop from embryos: small masses of unspecialized cells Simple animals can regenerate or grow back missing parts Most animals ingest their food and then digest it in some kind of internal cavity.

Animal Diversity Somewhere around 9 or 10 million species of animals inhabit the earth. About 800, 000 species have been identified.

Animal Phyla- Biologists recognize about 36 separate phyla within the Kingdom Animalia. (We’ll study the 10 major ones!)

Animal Movement Most animals are capable of complex and relatively rapid movement compared to plants and other organisms. Organisms that live rooted to one spot are sessile and those that move around are motile. Even the most sessile animals can move at least part of their bodies. This movement is dependent on how animals obtain food.

Animal Reproduction Most animals reproduce sexually, by means of differentiated haploid cells (eggs and sperm) Most animals are diploid, meaning that the cells of adults contain two copies of the genetic material.

Animal Sizes Animals range in size from no more than a few cells to organisms weighing many tons! a mesozoan blue whale

Animal Habitats Most animals inhabit the seas, with fewer in fresh water and even fewer on land.

Animal Cell Diagram

Animal Bodies The bodies of most animals (all except sponges) are made up of cells organized into tissues. Each tissue is specialized to perform specific functions. In most animals, tissues are organized into even more specialized organs. Organs form organ systems. This is how an organism develops. These cells have to differentiate and become specialized in various ways.

Animal Systems Skeletal- Support, protection- Bones, shells, cartilage Muscular- Movement; Muscle tissue (smooth, striated, cardiac) Digestion- Digestion of food and absorption of nutrients. Mouth, stomach, intestine Circulatory- Distribution of nutrients and oxygen; removal of wastes-Heart, blood vessels, blood Respiratory- Absorption of oxygen; removal of CO 2 -Lungs, gills Excretory- Removal of wastes-Kidneys Nervous- Perception, control of movement, control and coordination of organ system activities-Brain, spinal cord, nerves Endocrine- Control and coordination of organ system activities-Glands Immune- Defense against disease-causing organisms. Blood cells, glands, skin

Animal Symmetry The most primitive animals are asymmetrical. Cnidarians and echinoderms are radially symmetrical. Most animals are bilaterally symmetrical.

Radial Symmetry Forms that can be divided into similar halves by more than two planes passing through it. Animals with radial symmetry are usually sessile, free-floating, or weakly swimming.

Radially Symmetrical Like a wheel, animals with this spend most of their time floating like a buoy or attached to rocks. Differences between the dorsal and ventral surfaces allow jellyfish to float upright; sea anemones grip rocks with their ventral surfaces and collect food with their specialized dorsal surfaces. Advantages: Architects and engineers use radially symmetrical designs for structures such as fire hydrants and lighthouses so that the structures will be accessible or visible from any horizontal direction

Bilateral Symmetry Animals with bilateral symmetery are most well-suited for directional movement. Anterior (front end), and posterior (rear) end The left and right sides of most animals are nearly mirror images. Advantages: A. This body plan works well for animals, if a body part is damaged, the animal can rely on an identical part on its other side. B. This symmetry provides balance that aids movement. C. Anterior and dorsal defenses such as bones, shells, and horns protect delicate internal organs.

Radial vs. Bilateral Symmetry

Cephalization Bilateral Symmetry usually has led to cephalization — the process by which sensory organs and appendages became localized in the head (anterior) end of animals.

Evolutionary Trends If we analyze the basic body plans of animals, we find that they illustrate evolutionary trends. Four major “advances” (in order): 1. 2. 3. 4. Multicellular body plan Bilaterally symmetrical body plan “Tube-within-a-tube” body plan Coelomate body plan

3 Major Bilateral Body Plans 1. Acoelomates (A-SEE-LOWMATES) 2. Pseudocoelomates 3. Coelomates Each plan consists of 3 cell layers: endoderm, mesoderm, ectoderm

Acoelomates These animals have no other cavity than the gut. They are often called the “solid worms. ”

Pseudocoelomates These animals have a body cavity (the pseudocoelom) which is not completely lined with mesoderm. The “tube within a tube” body plan. This category is also composed of mostly worms.

Coelomates These animals have a “true coelom” lined with mesodermal peritoneum. Most animals are coelomate (EARTHWORM)

KINGDOM ANIMALIA: 10 PHYLA 1. 2. 3. 4. 5. 6. 7. 8. 9. Porifera Cnidaria Rotifera Platyhelminthes Nematoda Annelida Mollusca Arthropoda Echinodermata 10. Chordata Vertebrates Invertebrates

Protostomes Bilaterians Radial symmetry Bilateral symmetry Eumetazoans No true tissues True tissues Ancestral colonial protist Nematodes Arthropods Annelids Molluscs Flatworms Chordates Echinoderms Cnidarians Sponges gure 18. 4 Deuterostomes

Phylum Porifera Sponges Very primitive, no true tissues Supported by spongin (protein fibers) or spicules (mineral crystals) Sessile animals live attached to rocks. Get food/ oxygen from water that is pumped through their hollow bodies by cells with flagella Filter feeders Reproduce through budding and sperm/eggs

Phylum Porifera

Flagellated choanocytes - Filter food / O 2 from the water passing through the porous body Pores Choanocyte Amoebocyte Skeletal fiber Central cavity Figure 18. 5 D Choanocyte in contact with an amoebocyte Water flow Flagella

Phylum Cnidaria Have true tissue; no organs Have a simple skeletal system Excretion through same opening used to pump food/ water through Free-floating or sessile 2 stages of life cycle- medusa/polyp Budding/sexual reproduction

Polyp stage Cnidaria: Corals, Jellyfish, Sea Anemones Medusa stage

Cnidarians have a gastrovascular cavity and cnidocytes on tentacles that sting prey Capsule (nematocyst) Coiled thread Tentacle “Trigger” Discharge of thread Prey Figure 18. 6 D Cnidocyte

PHYLUM ROTIFERA Very small size and mostly soft bodies Microscopic, mostly aquatic-found in many freshwater and moist soil Complete digestive tract with mouth and anus Body cavities that are partially lined by mesoderm- coelomates. Crown of cilia around the mouth of the rotifer that makes them appear to whirl like a wheel Tiny mouths; primarily omnivorous, unicellular algae and other phytoplankton Sexual reproduction

Phylum Rotifera

Unsegmented Worms Roundworms and flatworms are among the simplest bilaterally symmetrical animals Flatworms don’t need respiratory or circulatory systems Thin flat bodies absorb oxygen and release CO 2 and wasted directly in the surrounding water. Considered parasitic, they live in the digestive systems of other animals. Nematodes, or roundworms, are less than 1 mm long. There are loads of nematodes in soil and water. Some are decomposers others parasites of animals or plants Pinworms and hookworms in soil burrow into the skin of people who go barefoot outdoors Trichina worms infest people who eat undercooked pork or wild game.

Phylum Platyhelminthes Flatworms (tapeworms, Planaria) 3 cell layers- Acoelomates Bilaterally symmetrical No respiratory or circulatory systems; gastrovascular cavity and organized response mechanisms Thin flat bodies absorb oxygen and release CO 2 and wasted directly in the surrounding water. Reproduce by splitting in 2 Some parasitic, they live in the digestive systems of other animals.

A planarian has a gastrovascular cavity and a simple ner vous system Gastrovascular cavity Nerve cords Mouth Eyespots Nervous tissue clusters Figure 18. 7 A Bilateral symmetry

Flukes and tapeworms are parasitic flatworms Colorized SEM 80 Units with reproductive structures Figure 18. 7 B Hooks Sucker Scolex (anterior end)

Phylum Nematoda Roundworms Less than 1 mm long; Live in soil and water. Sexual reproduction- male sperm/female egg Some are decomposers, others are parasites of animals or plants Pseudocoelom; complete digestive system Pinworms and hookworms in soil burrow into the skin of people who go barefoot outdoors; Trichina worms infest people who eat undercooked pork or wild game. (cause “Elephantitis”- swelling of appendages due to blocking of fluid movement in blood vessels by worms)

Phylum Nematoda

Simple Invertebrates Lab Covers Porifera, Rotifers, Nematoda, Cnidaria, and Platyhelminthes

Animalia Notes continued in Part 2 power point….