Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
26-1 Introduction to the Animal Kingdom Slide 1 of 49 Copyright Pearson Prentice Hall Slide 2 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom What Is an Animal? What Is an Animal? Animals are multicellular, eukaryotic heterotrophs whose cells lack cell walls. Slide 3 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom What Animals Do to Survive Animals carry out the following essential functions: • feeding • respiration • circulation • excretion • response • movement • reproduction Slide 4 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom What Animals Do to Survive Many body functions help animals maintain homeostasis, or a relatively stable internal environment. Homeostasis is often maintained by internal feedback mechanisms called feedback loops. Most feedback loops involve feedback inhibition, in which the product or result of a process stops or limits the process. Slide 5 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Complex animals tend to have: • high levels of cell specialization and internal body organization • bilateral body symmetry • a front end or head with sense organs • a body cavity Slide 6 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution The zygote undergoes a series of divisions to form a blastula, a hollow ball of cells. Slide 7 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Ectoderm A protostome is an animal whose mouth is formed from the blastopore. Mesoderm Endoderm Blastopore Most invertebrate animals are protostomes. Anus Blastopore becomes mouth Copyright Pearson Prentice Hall Slide 8 of 49 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Ectoderm A deuterostome is an animal whose anus is formed from the blastopore. Mesoderm Endoderm Blastopore The anus is the opening through which wastes leave the digestive tract. Mouth Blastopore becomes anus Copyright Pearson Prentice Hall Slide 9 of 49 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Echinoderms and vertebrates are both deuterostomes. Slide 10 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution This similarity in embryology may indicate that vertebrates have a closer evolutionary relationship to echinoderms than to other invertebrates. Slide 11 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution The cells of the endoderm, or innermost germ layer, develop into the linings of the digestive tract and much of the respiratory system. Only the label “endoderm” should appear on this slide. Endoderm Slide 12 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution The cells of the mesoderm, or middle layer, develop into muscles and much of the circulatory, reproductive, and excretory organ systems. Mesoderm Slide 13 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution The ectoderm, or outermost layer, develops into the sense organs, nerves, and the outer layer of the skin. Ectoderm Slide 14 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Body Symmetry Except for sponges, every animal exhibits some body symmetry in its structure. Many simple animals, like the sea anemone, have body parts that repeat around the center of the body. Slide 15 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Radial symmetry These animals exhibit radial symmetry, in which any number of imaginary planes can be drawn through the center, each dividing the body into equal halves. Planes of symmetry Copyright Pearson Prentice Hall Slide 16 of 49 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution In animals with bilateral symmetry, only one imaginary plane can divide the body into two equal halves—left and right. Plane of symmetry Bilateral symmetry Slide 17 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Posterior end The anterior is the front end. The posterior is the back end. Trends in Animal Evolution Anterior end Bilateral symmetry Slide 18 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom The dorsal is the upper side. Trends in Animal Evolution Dorsal side The ventral is the lower side. Ventral side Bilateral symmetry Slide 19 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Bilateral symmetry allows for segmentation, in which the body is constructed of many repeated and similar parts, or segments. The combination of bilateral symmetry and segmentation is found in two successful animal groups—arthropods and vertebrates. Slide 20 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Cephalization Animals with bilateral symmetry exhibit cephalization, which is the concentration of sense organs and nerve cells at the front end of the body. Slide 21 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Animals with bilateral symmetry usually move with the anterior end forward, so this end comes in contact with new parts of the environment first. As sense organs have evolved, they have tended to gather at the anterior end, as have nerve cells that process information and “decide” what the animal should do. Slide 22 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Trends in Animal Evolution Body Cavity Formation Most animals have a 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 so that they are not pressed on by muscles or twisted out of shape by body movements. Slide 23 of 49 Copyright Pearson Prentice Hall 26-1 Introduction to the Animal Kingdom Body Cavity Formation Slide 24 of 49 Copyright Pearson Prentice Hall 26-1 Click to Launch: Continue to: - or - Slide 25 of 49 Copyright Pearson Prentice Hall 26-1 Homeostasis is often maintained by feedback loops that involve a. gastrulation. b. feedback inhibition. c. spontaneous generation. d. equilibrium. Slide 26 of 49 Copyright Pearson Prentice Hall 26-1 Animals respond to events in their environments using specialized cells called a. muscle cells. b. nerve cells. c. gametes. d. blood cells. Slide 27 of 49 Copyright Pearson Prentice Hall 26-1 A characteristic that all animals share is being a. heterotrophic. b. autotrophic. c. prokaryotic. d. anaerobic. Slide 28 of 49 Copyright Pearson Prentice Hall 26-1 Excretion is a function of all animals that involves a. exchange of oxygen and carbon dioxide. b. transport of material from one part of the body to another. c. digestion and absorption of food molecules. d. removal of metabolic wastes. Slide 29 of 49 Copyright Pearson Prentice Hall 26-1 One major trend in animal evolution has been a. the simplification of body organ systems. b. an increase in the degree of cephalization. c. a shift from bilateral symmetry to radial symmetry. d. disappearance of the blastula stage in early development. Slide 30 of 49 Copyright Pearson Prentice Hall END OF SECTION