Campbell Biology, Third Canadian Edition - Chapter 32: An Overview of Animal Diversity PDF

Campbell Biology Third Canadian Edition Chapter 32 An Overview of Animal Diversity * With added material Copyright © 2021 Pearson Canada, Inc....

Campbell Biology Third Canadian Edition Chapter 32 An Overview of Animal Diversity * With added material Copyright © 2021 Pearson Canada, Inc. 1 2  3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved  What is an animal? 4 Animals are: Multicellular Heterotrophic Eukaryotic Moveable (motile) No cell wall Go through Blastula Copyright © 2020 Pearson Education, Inc. All Rights Reserved Key Concepts Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers The history of animals spans more than half a billion years Animals can be characterized by “body plans” New views of animal phylogeny continue to be shaped by new molecular data Copyright © 2021 Pearson Canada, Inc. 5 Overview: Welcome to Your Kingdom The animal kingdom extends far beyond humans and other animals we commonly encounter Scientists have identified 1.3 million living species of animals Copyright © 2021 Pearson Canada, Inc. 6 Nutritional Mode Animals are heterotrophs: – They cannot construct all their own organic molecules – They obtain organic molecules from their food, that they ingest and digest within their bodies Copyright © 2021 Pearson Canada, Inc. 7 Cell Structure and Specialization Animals are multicellular eukaryotes They lack cell walls Their bodies are held together by structural proteins such as collagen Nervous tissue and muscle tissues are unique, defining characteristics of animals Tissues are groups of cells that act as a functional unit Copyright © 2021 Pearson Canada, Inc. 8  9 Copyright © 2020 Pearson Education, Inc. All Rights Reserved  10 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Animals can be characterized by “body plans” Zoologists sometimes categorize animals according to a body plan, a set of morphological and developmental traits Some body plans have been conserved, while other have changed multiple times over the course of evolution – The molecular control of gastrulation has remained unchanged for more than 500 million years Copyright © 2021 Pearson Canada, Inc. 11 Symmetry (1 of 3) Animals can be categorized according to symmetry of their bodies, or lack of it Some have radial symmetry, with no front and back, or left and right Figure 32.8 Body symmetry. Copyright © 2021 Pearson Canada, Inc. 12 Symmetry (2 of 3) Two-sided symmetry is called bilateral symmetry Bilaterally symmetrical animals have: – A dorsal (top) side and a ventral (bottom) side – A right and left side – Anterior (front) and posterior (back) ends – Many also have sensory ”equipment” concentrated at the anterior end (development of a head), which is called cephalization Copyright © 2021 Pearson Canada, Inc. 13 Symmetry (3 of 3) Radial animals are often sessile or planktonic (drifting or weakly swimming) Bilateral animals often move actively and have a central nervous system Copyright © 2021 Pearson Canada, Inc. 14  15 Copyright © 2020 Pearson Education, Inc. All Rights Reserved  16 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Reproduction and Development (1 of 2) Most animals reproduce sexually, with diploid stage usually dominating life cycle After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage Cleavage leads to formation of a multicellular, hollow blastula The blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues Copyright © 2021 Pearson Canada, Inc. 17 BioFlix: Sea Urchin Embryonic Development Video: Sea Urchin Embryonic Development Copyright © 2021 Pearson Canada, Inc. 18 Tissues (1 of 3) Animal body plans also vary according to the organization of the animal’s tissues Tissues are collections of specialized cells isolated from other tissues by membranous layers During development, three germ layers give rise to tissues and organs of animal embryos Copyright © 2021 Pearson Canada, Inc. 19 Tissues (2 of 3) Ectoderm is the germ layer covering the embryo’s surface Endoderm is the innermost germ layer and lines the developing digestive tube, called archenteron Copyright © 2021 Pearson Canada, Inc. 20 Tissues (3 of 3) Diploblastic animals have ectoderm and endoderm – Includes cnidarians and a few other groups Triploblastic animals also have an intervening mesoderm layer; these include all bilaterians – Includes flatworms, arthropods, vertebrates, and others Copyright © 2021 Pearson Canada, Inc. 21  22 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Trichoplax adhaerens (Tp) is 23 considered the simplest animal. TP used to be the only living species in the phylum Placozoa (4 are known now). Copyright © 2020 Pearson Education, Inc. All Rights Reserved  24 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Body cavities of triploblastic animals (3 of 3) Triploblastic animals that lack a body cavity are called acoelomates Figure 32.9 Body cavities of triploblastic animals. Copyright © 2021 Pearson Canada, Inc. 25 Body cavities of triploblastic animals (2 of 3) A pseudocoelom is a body cavity derived from mesoderm and endoderm Triploblastic animals possessing a pseudocoelom called pseudocoelomates Figure 32.9b Body cavities of triploblastic animals. Copyright © 2021 Pearson Canada, Inc. 26 Body cavities of triploblastic animals (1 of 3) Coelomates are animals that possess a true coelom Figure 32.9a Body cavities of triploblastic animals. Copyright © 2021 Pearson Canada, Inc. 27  28 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Protostome and Deuterostome Development Based on early development, many animals can be categorized as having protostome development or deuterostome development Copyright © 2021 Pearson Canada, Inc. 29 Cleavage (1 of 2) In protostome development, cleavage spiral and determinate In deuterostome development, cleavage radial and indeterminate Figure 32.10a A comparison of protostome and deuterostome development. Copyright © 2021 Pearson Canada, Inc. 30 Cleavage (2 of 2) With indeterminate cleavage, each cell in the early stages of cleavage retains the capacity to develop into a complete embryo Indeterminate cleavage makes possible identical twins, and embryonic stem cells Copyright © 2021 Pearson Canada, Inc. 31  32 Copyright © 2020 Pearson Education, Inc. All Rights Reserved  33 Copyright © 2020 Pearson Education, Inc. All Rights Reserved Ecdysozoa Ecdysozoans are invertebrates that shed their exoskeletons through a process called ecdysis Figure 32.12 Ecdysis. Copyright © 2021 Pearson Canada, Inc. 34  35 Arthropods Copyright © 2020 Pearson Education, Inc. All Rights Reserved  36 Arthropods Copyright © 2020 Pearson Education, Inc. All Rights Reserved Lophotrochozoans Some lophotrochozoans have a feeding structure called a lophophore Others have distinct developmental stage called trochophore larva Figure 32.13 Ecdysis. Copyright © 2021 Pearson Canada, Inc. 37 Reproduction and Development (2 of 2) Most animals have at least one larval stage A larva is sexually immature and morphologically distinct from the adult; it eventually undergoes metamorphosis to become a juvenile A juvenile resembles an adult, but is not yet sexually mature Copyright © 2021 Pearson Canada, Inc. 38 Concept 32.3: Animals can be characterized by “body plans” Zoologists sometimes categorize animals according to a body plan, a set of morphological and developmental traits Some body plans have been conserved, while other have changed multiple times over the course of evolution – The molecular control of gastrulation has remained unchanged for more than 500 million years Copyright © 2021 Pearson Canada, Inc. 39 Reproduction and Development (2 of 2) Most animals, and only animals, have Hox genes regulating development of body form Although the Hox family of genes is highly conserved, it can produce a wide diversity of animal morphology Copyright © 2021 Pearson Canada, Inc. 40  41 Copyright © 2020 Pearson Education, Inc. All Rights Reserved An Overview of Animal Diversity (2 of 4) THINK-PAIR-SHARE What do plants and animals have in common? Copyright © 2021 Pearson Canada, Inc. 42 Concept 32.2: The history of animals spans more than half a billion years The animal kingdom includes a great diversity of living species and an even greater diversity of extinct ones Copyright © 2021 Pearson Canada, Inc. 43 Concept 32.2: The history of animals spans more than half a billion years The common ancestor of all living animals likely lived between 700 and 770 million years ago Morphological and molecular data suggest that the common ancestor may have resembled modern choanoflagellates, protists that are closest living relatives of animals Copyright © 2021 Pearson Canada, Inc. 44 Three lines of evidence that choanoflagellates are closely related to animals 1. Cell morphology 2. Cell morphology unique to animal cells 3. DNA sequence homology Figure 32.3 Three lines of evidence that choanoflagellates are closely related to animals. Copyright © 2021 Pearson Canada, Inc. 45  46 Dr. Nicole King https://www.youtube.com/watch?v=1v6cgSkiHik Copyright © 2020 Pearson Education, Inc. All Rights Reserved Campbell Biology Third Canadian Edition NEXT Chapter 40 Basic Principles of Animal Form and Function Copyright © 2021 Pearson Canada, Inc. 47