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Introduction to Animals Chapter 32 650-667 blue book Unit 7 Chapter 25p. 729-744 http://www.animalearn.org/ Chapter 32 Kingdom Animalia 1 Key points • Id four important characteristics of animals • List two kinds of tissues found only in animals • Explain how the first animals may have evolved from unicellular organisms • Id two functions of the body cavity • List the structural features that taxonomists use to classify animals Chapter 32 Kingdom Animalia 2 The Nature of Animals If you are asked to name an animal, you might respond with the name of a familiar large-bodied animal, such as a horse, a shark, or an eagle. But the kingdom Animalia is much more diverse than many people realize!! Chapter 32 Kingdom Animalia 3 Characteristics • • • • • Multicellular Heterotrophic organisms Lack cell walls Some have a backbone- vertebrates Some do not have a backboneinvertebrates (95% of all animal species alive today) (33 phyla) • Sexual reproduction Chapter 32 Kingdom Animalia 4 Multicellular Organization • Specialization- is the evolutionary adaptation of a cell for a particular function. Specialized cells perform particular functions (digestion, excretion) Cells tissues organs systems Allows for the ability to evolve and adapt Chapter 32 Kingdom Animalia 5 What Animals Do to Survive – What essential functions must animals perform to survive? – Like all organisms, animals must maintain homeostasis by gathering and responding to information, obtaining and distributing oxygen and nutrients, and collecting and eliminating carbon dioxide and other wastes. They also reproduce. Heterotrophy and Movement • Must eat other organisms • Ingestion- animal takes in organic material or food (other living things) • Digestion- occurs in the animals body • elimination of wastes • Most motile some attached • Nervous tissue (stimuli) • Muscle tissue- (response) Chapter 32 Kingdom Animalia 7 Obtaining and Distributing Oxygen and Nutrients – After acquiring oxygen and nutrients, animals must transport them to cells throughout their bodies by using some kind of circulatory system. – The structures and functions of respiratory and digestive systems must work together with circulatory systems. Gathering and Responding to Information – The nervous system gathers information using cells called receptors that respond to sound, light, chemicals, and other stimuli. – Other nerve cells collect and process that information and determine how to respond. Sexual reproduction and development • Most sexual • Some asexual (sponges, hydra) • Zygote- diploid cell produced from 2 haploid cells (mitosis) • Differentiation- cells become specialized Chapter 32 Kingdom Animalia 10 Chapter 32 Kingdom Animalia 11 Chordates – Fewer than 5 percent of animal species are chordates, members of the clade commonly known as Phylum Chordata. – All chordates exhibit four characteristics during at least one stage of life: a dorsal, hollow nerve cord; a notochord; a tail that extends beyond the anus; and pharyngeal pouches. Invertebrates vs chordates • • • • • • • Some no body symmetry Some no true tissue Some bilateral symmetry Some specialized parts NO Backbone!! Make up most # (spiders, sponges, arthropods) Chapter 32 Kingdom Animalia • Notochord- firm, flexible rod of tissue located in the dorsal part of the body (most embryos) • Dorsal nerve cordhollow tube above the notochord, will develop into brain and spinal cord, • Pharyngeal pouchessmall out pockets of the anterior digestive track may develop into gills used for gas exchange 13 Body structure 3 major body plans- animals shape, symmetry and internal organization 1. Asymmetrical- no symmetry, sponges 2. Radial- body parts organized in a circle around an axis (sea anemone, Cnidarians) 3. Bilateral symmetry- two similar halves Chapter 32 Kingdom Animalia 14 Chapter 32 Kingdom Animalia 15 Body structure Terms: • Dorsal (back) • Anterior (towards head) • posterior (towards tail) • ventral (abdomen • HR clip sect1 Chapter 32 Kingdom Animalia 16 Key points • Compare symmetry, segmentation, and body support in invertebrates and vertebrates • Describe the differences in the respiratory and circulatory systems of invertebrates and vertebrates • Contrast reproduction and development in invertebrates and vertebrates Chapter 32 Kingdom Animalia 17 Invertebrates and vertebrates Comparative anatomy, the study of the structure of animal bodies, is one of the oldest disciplines in biology. Some modern scientists work to establish the relationship between different animals, while others try to establish the relationship between the form and function of morphological features of animals and the role of these features in animal ecology. Chapter 32 Kingdom Animalia 18 Invertebrate characteristics Symmetry • Radial or bilateral - Segmentation-series of repeating similar units - cephalization-Animals with bilateral symmetry typically exhibit, the concentration of sense organs and nerve cells at their anterior end (brain) Support• Simple skeleton • Fluid-filled body cavity • Exoskeleton- rigid outer covering Chapter 32 Kingdom Animalia 19 Invertebrate characteristics Respiratory/ circulatory system• Gills- organs that consist of blood vessels surrounded by a membrane specialized for gas exchange in water, aquatic arthropods, mollusks • Open circulatory system- fluid pumped by the heart through vessels and into the body cavity to vessels (arthropods and some mollusks) • Closed- blood pumped by a heart and circulates through the body in vessels that from a closed loop (Annelids and humans) Chapter 32 Kingdom Animalia 20 Chapter 32 Kingdom Animalia 21 Invertebrate characteristics Digestive and excretory system • Central chambers (one opening, Cnidarians) • Gut- digestive tract • Some wastes excreted as dissolved gas Nervous system • Some no neurons (sponges) • Most neurons Chapter 32 Kingdom Animalia 22 Invertebrate characteristics Reproduction and Development • Sexual reproduction • Hermaphrodite- organism that produces both male and female gametes (earthworms) • Larva- free-living, immature form (indirect development- does not look like adult) Zygoteyoung larva older larva Pupa adult • Direct development- looks like adult, no larval stages occur Chapter 32 Kingdom Animalia 23 Chapter 32 Kingdom Animalia 24 Vertebrate Characteristics • Have a backbone- fishes, amphibians, reptiles, birds, and mammals • Most are terrestrial • Two broad categories for survival 1. support of the body 2. conserve water Chapter 32 Kingdom Animalia 25 Question? • In many animals, the larva is morphologically and ecologically distinct from the adult. The larva may live in a different habitat from the adult, feed on different foods, or be active at different times of the day or year. For example, caterpillars feed on vegetation, while butterflies feed on nectar. Explain the possible adaptive advantages of such ecological differences. Chapter 32 Kingdom Animalia 26 Vertebrate Characteristics Segmentation and body support • vertebrae- repeating bony units of backbone • endoskeleton- internal skeleton made of bone and cartilage, backbone, grows as animal grows Body coveringsintegument, composed of water-filled cells (death), (for gas exchange moist skinned animals, water tight birds and reptiles) Chapter 32 Kingdom Animalia 27 Vertebrate Characteristics Respiratory and Circulatory system • Gills in aquatic vertebrates • Lungs- organs for gas exchange • Closed circulatory system with a multi chambered heart Digestive and Excretory system Mouth gut anus Kidneys- filter wastes from blood, regulate h2o levels Nervous System- highly organized Fyi- human digestive track is about 7m or 23ft long • HR clip sect2 Chapter 32 Kingdom Animalia 28 Key points • List the steps of fertilization and development through gastrulation • List two body parts from each germ layer • Id the three different body cavity structures of animals • Name the categories of animals that undergo spiral cleavage and radial cleavage • Contrast the two processes of coelom formation Chapter 32 Kingdom Animalia 29 Fertilization and Development development of a multicellular animal from an egg cell is a truly remarkable process. Each cell in an animal has the same set of genes that are used to build the animal , yet animals have many different kinds of cells. From the fertilized egg come large numbers of cells- trillions in humans- that consistently give rise to structural features of the animal body Chapter 32 Kingdom Animalia 30 Fertilization and early development • Fertilization is the union of female and male gametes to form a zygote • Gametes- egg and sperm • Cleavage- series of cell divisions • Blastula- a hollow ball of cells • Gastrulation – transforms the blastula into a multilayered embryo call the gastrula • Archenteron- primitive gut develops, deep cavity in the embryo • Blastopore- open end of the archenteron • Ectoderm- outer germ layer • Endoderm- inner germ layer • Mesoderm- forms between the ecto and endo Chapter 32 Kingdom Animalia 31 Patterns of Embryological Development – Every animal that reproduces sexually begins life as a zygote, or fertilized egg. – As the zygote begins to develop, it forms a blastula, a hollow ball of cells. Chapter 32 Kingdom Animalia 33 Patterns of Embryological Development – As the blastula develops, it folds in on itself, forming an elongated structure with a tube that runs from one end to the other. This tube becomes the digestive tract. Patterns of Embryological Development – – At first this digestive tract has only a single opening. However, an efficient digestive tract needs two openings. In phyla that are protostomes, the blastopore becomes the mouth. In protostomes, including most invertebrates, the anus forms from a second opening, which develops at the opposite end of the tube. Patterns of Embryological Development – In deuterostomes, the blastopore becomes the anus, and the mouth is formed from a second opening that develops. Chordates and echinoderms are deuterostomes. Cleavage and Blastopore Fate • Some times the blastopore will develop into a mouth and the second opening forms the anus protostomes (mouth first) Mollusks, arthropods, annelids • Sometimes the blastopore will develop into an anus and the second becomes the mouth deuterostomes (mouth second) Echinoderms and chordates Chapter 32 Kingdom Animalia 37 Chapter 32 Kingdom Animalia 38 Differentiation of Germ Layers – During embryological development, the cells of most animal embryos differentiate into three layers called germ layers. – Cells of the endoderm, or innermost germ layer, develop into the linings of the digestive tract and much of the respiratory system. – Cells of the mesoderm, or middle layer, give rise to muscles and much of the circulatory, reproductive, and excretory organ systems. – The ectoderm, or outermost layer, produces sense organs, nerves, and the outer layer of the skin. Chapter 32 Kingdom Animalia 40 Formation of a Body Cavity – Most animals have some kind of body cavity—a fluid-filled space between the digestive tract and body wall. – A body cavity provides a space in which internal organs can be suspended and room for those organs to grow. Types of cavities • Acoelomates- do not have a body cavity, interior of the animal is solid (flatworms) • Pseudocoleom- false body cavity, not completely lined by mesoderm (roundworms) • Coelom- complete body cavity, mesoderm lines the body cavity and surrounds and supports the endodermic gut Chapter 32 Kingdom Animalia 42 Formation of a Body Cavity – Most complex animal phyla have a true coelom, a body cavity that develops within the mesoderm and is completely lined with tissue derived from mesoderm. Formation of a Body Cavity – Some invertebrates have only a primitive jellylike layer between the ectoderm and endoderm. – Other invertebrates lack a body cavity altogether, and are called acoelomates. Formation of a Body Cavity – Still other invertebrate groups have a pseudocoelom, which is only partially lined with mesoderm. Chapter 32 Kingdom Animalia 46 Chapter 32 Kingdom Animalia 47 The Cladogram of Animals – – This cladogram presents our current understanding of relationships among animal phyla. During the course of evolution, important traits evolved, as shown by the red circles. Chapter 32 Kingdom Animalia 49 Chapter 32 Kingdom Animalia 50 Chapter 32 Kingdom Animalia 51