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Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell.

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Presentation on theme: "Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell."— Presentation transcript:

1 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Chapter 32 An Introduction to Animal Diversity

2 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overview: Welcome to Your Kingdom Largest Kingdom, multicellular, heterotrophic, gametes produced in gonads (ovaries & testes) Life evolved in the sea. The few animal groups that successfully colonized fresh water and land and evolved many adaptations of structure, function, and reproduction to these different environments. Most animals are made u of three layers: an outer protective and sensory tube, an inner digestive tube, and between them the organs of motion, reproduction, excretion, and transport. Active carnivores made many of the major evolutionary advances among animals, but most groups then radiated to produce members with other lifestyles such as herbivory, sessile filter feeding, or parasitism. (Sun coral catching and eating live brine)http://www.youtube.com/watch?v=sTtJlyBcSv0&feature=related

3 Fig. 32-1

4 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings There are exceptions to nearly every criterion for distinguishing animals from other life-forms Several characteristics, taken together, sufficiently define the group Animals are heterotrophs that ingest their food Animals are multicellular eukaryotes Their cells lack cell walls Their bodies are held together by structural proteins such as collagen Nervous tissue and muscle tissue are unique to animals Concept 32.1: Animal are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers

5 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Reproduction and Development Most animals reproduce sexually, with the diploid stage usually dominating the life cycle After a sperm fertilizes an egg, the zygote undergoes rapid cell division called cleavage Cleavage leads to formation of a blastula The blastula undergoes gastrulation, forming a gastrula with different layers of embryonic tissues (early embryonic development)http://www.youtube.com/watch?v=lXN_sDnd1ng&NR=1 (sea urchin gastrulation)http://www.youtube.com/watch?v=Lgb4wMsZwZA

6 Fig Zygote Cleavage Eight-cell stage

7 Fig Zygote Cleavage Eight-cell stage Cleavage Blastula Cross section of blastula Blastocoel

8 Fig Zygote Cleavage Eight-cell stage Cleavage Blastula Cross section of blastula Blastocoel Gastrulation Blastopore Gastrula Archenteron Ectoderm Endoderm Blastocoel

9 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Many animals have at least one larval stage A larva is sexually immature and morphologically distinct from the adult; it eventually undergoes metamorphosis All animals, and only animals, have Hox genes that regulate the development of body form Although the Hox family of genes has been highly conserved, it can produce a wide diversity of animal morphology

10 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 32.2: The history of animals spans more than half a billion years The Cambrian explosion (535 to 525 million years ago) marks the earliest fossil appearance of many major groups of living animals There are several hypotheses regarding the cause of the Cambrian explosion – New predator-prey relationships – predators acquired novel adaptations, such as forms of locomotion that helped them catch prey, while prey species acquired new defenses, such as protective shells – A rise in atmospheric oxygen – greater oxygen availability would have provided opportunities for animals with higher metabolic rates and larger body sizes to thrive – The evolution of the Hox gene complex – provided the developmental flexibility that resulted in variations in morphology

11 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Animals can be categorized according to the symmetry of their bodies, or lack of it Some animals have radial symmetry 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 (head) and posterior (tail) ends – Cephalization, the development of a head

12 Fig (a) Radial symmetry (b) Bilateral symmetry

13 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tissues Animal body plans also vary according to the organization of the animals tissues Tissues are collections of specialized cells isolated from other tissues by membranous layers During development, three germ layers give rise to the tissues and organs of the animal embryo Ectoderm is the germ layer covering the embryos surface Endoderm is the innermost germ layer and lines the developing digestive tube, called the archenteron Diploblastic animals have ectoderm and endoderm Triploblastic animals also have an intervening mesoderm layer; these include all bilaterians

14 Fig Coelom Body covering (from ectoderm) Digestive tract (from endoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) (a) Coelomate Body covering (from ectoderm) Pseudocoelom Digestive tract (from endoderm) Muscle layer (from mesoderm) (b) Pseudocoelomate Body covering (from ectoderm) Tissue- filled region (from mesoderm) Wall of digestive cavity (from endoderm) (c) Acoelomate Body Cavities Most triploblastic animals possess a body cavity

15 Fig. 32-8a Coelom Body covering (from ectoderm) Digestive tract (from endoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) (a) Coelomate A true body cavity is called a coelom and is derived from mesoderm Coelomates are animals that possess a true coelom

16 Pseudocoelom Body covering (from ectoderm) Muscle layer (from mesoderm) Digestive tract (from endoderm) (b) Pseudocoelomate A pseudocoelom is a body cavity derived from the mesoderm and endoderm Triploblastic animals that possess a pseudocoelom are called pseudocoelomates

17 (c) Acoelomate Body covering (from ectoderm) Wall of digestive cavity (from endoderm) Tissue- filled region (from mesoderm) Triploblastic animals that lack a body cavity are called acoelomates

18 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Protostome and Deuterostome Development Based on early development, many animals can be categorized as having protostome development or deuterostome development In protostome development, cleavage is spiral and determinate In deuterostome development, cleavage is radial and indeterminate 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

19 Fig Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderm, chordates) Eight-cell stage Spiral and determinate Radial and indeterminate Coelom Archenteron (a) Cleavage (b) Coelom formation Coelom Key Ectoderm Mesoderm Endoderm Mesoderm Blastopore Solid masses of mesoderm split and form coelom. Folds of archenteron form coelom. AnusMouth Digestive tube MouthAnus Mouth develops from blastopore.Anus develops from blastopore. (c) Fate of the blastopore

20 Eight-cell stage (a) Cleavage Spiral and determinate Radial and indeterminate Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) In protostome development, cleavage is spiral and determinate In deuterostome development, cleavage is radial and indeterminate 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 Cleavage

21 Coelom Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) (b) Coelom formation Key Ectoderm Mesoderm Endoderm Mesoderm Coelom Archenteron Blastopore Solid masses of mesoderm split and form coelom. Folds of archenteron form coelom. Coelom Formation In protostome development, the splitting of solid masses of mesoderm forms the coelom In deuterostome development, the mesoderm buds from the wall of the archenteron to form the coelom

22 Anus Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderms, chordates) Anus Mouth Digestive tube (c) Fate of the blastopore Key Ectoderm Mesoderm Endoderm Mouth develops from blastopore.Anus develops from blastopore. Fate of the Blastopore The blastopore forms during gastrulation and connects the archenteron to the exterior of the gastrula In protostome development, the blastopore becomes the mouth In deuterostome development, the blastopore becomes the anus

23 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 32.4: New views of animal phylogeny are emerging from molecular data Zoologists recognize about three dozen animal phyla Current debate in animal systematics has led to the development of two phylogenetic hypotheses, but others exist as well One hypothesis of animal phylogeny is based mainly on morphological and developmental comparisons (This is the one we will follow in chapters 33 & 34) One hypothesis of animal phylogeny is based mainly on molecular data

24 Fig ANCESTRAL COLONIAL FLAGELLATE Metazoa Eumetazoa Porifera Bilateria Deuterostomia Protostomia Cnidaria Ctenophora Ectoprocta Brachiopoda Echinodermata Chordata Platyhelminthes Rotifera Mollusca Annelida Arthropoda Nematoda Phylogeny based mainly on morphological and developmental comparison

25 Fig Silicea ANCESTRAL COLONIAL FLAGELLATE Metazoa Eumetazoa Porifera Bilateria Deuterostomia Lophotrochozoa Ecdysozoa Calcarea Ctenophora Cnidaria Acoela Echinodermata Chordata Platyhelminthes Rotifera Ectoprocta Brachiopoda Mollusca Annelida Nematoda Arthropoda Phylogeny based mainly on molecular data

26 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Points of Agreement All animals share a common ancestor Sponges are basal animals Eumetazoa is a clade of animals (eumetazoans) with true tissues Most animal phyla belong to the clade Bilateria, and are called bilaterians Chordates and some other phyla belong to the clade Deuterostomia

27 Fig. 32-UN1 Common ancestor of all animals True tissues Sponges (basal animals) Ctenophora Cnidaria Acoela (basal bilaterians) Deuterostomia Lophotrochozoa Ecdysozoa Metazoa Eumetazoa Bilateria (most animals) Bilateral summetry Three germ layers

28 Fig. 32-T1

29 Fig. 32-UN2

30 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings You should now be able to: 1.List the characteristics that combine to define animals 2.Distinguish between the following pairs or sets of terms: radial and bilateral symmetry; diploblastic and triploblastic; spiral and radial cleavage; determinate and indeterminate cleavage; acoelomate, pseudocoelomate, and coelomate 3.Compare the developmental differences between protostomes and deuterostomes


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