Biological Science - Introduction to Animals PDF

BIOLOGICAL SCIENCE FIFTH EDITION Freeman Quillin Allison 33 An Introduction to Animals Lecture Presentation by Stephanie Scher Pandolfi, Michigan State University © 2014 Pearson Education, Inc. Roadmap 33 In this...

BIOLOGICAL SCIENCE FIFTH EDITION Freeman Quillin Allison 33 An Introduction to Animals Lecture Presentation by Stephanie Scher Pandolfi, Michigan State University © 2014 Pearson Education, Inc. Roadmap 33 In this chapter you will learn that Most animal phyla originated suddenly in the Cambrian period and then diversified by asking by asking by asking What is an What key innovations What are the animal? occurred during themes of animal 33.1 animal evolution? diversification? 33.2 33.3 looking closer at Non-bilaterian Protostome Deuterostome animals animals animals then and 33.4 Ch. 34 Ch. 35 © 2014 Pearson Education, Inc. Introduction  The radiation of animals began around 550 million years ago during the Cambrian explosion  Biologists estimate that there are between 8 million and 50 million extant animal species  The ancestors to animals were single- celled protists © 2014 Pearson Education, Inc. What Is an Animal?  Animals are eukaryotes that share key traits: 1.Multicellularity, with cells that – Lack cell walls – Have an extensive extracellular matrix 2.Heterotrophy – They obtain necessary carbon compounds from other organisms – Most ingest their food rather than absorbing it 3.Motility – They move under their own power at some © 2014 Pearson Education, Inc. What Is an Animal?  All animals except sponges also have 1. Nerve cells called neurons that transmit electrical signals to other cells 2. Muscle cells that can change the shape of the body  In most animals, neurons connect to by contracting each other, forming a nervous system – Some neurons connect to muscle cells – Muscles and neurons are adaptations that allow a large, multicellular body to move efficiently © 2014 Pearson Education, Inc. 33.2 – Key Innovations  Scientists look at three types of N evidence when studying evolution: Im ew fossils, morphology, and molecular pr a (genes) o v nd ed  Found supporting evidence of innovation !  Multicellularity  Embryonic tissue layers  Bilateral symmetry, cephalization and the nervous system  The Coelom  Protostomes vs. Deuterostomes  Segmentation © 2014 Pearson Education, Inc. Image: Wikimedia Commons Figure 33.2 Choanoflagellates Fungi ANIMALIA Choanoflagellates Porifera (sponges) ANIMALIA Multicellularity Ctenophora (comb jellies) Cnidaria (jellyfish, corals, sea anemones) Diploblasty Acoela (acoels) LOPHOTROCHOZOA Rotifera (rotifers) Loss of coelom Platyhelminthes Triploblasty (flatworms) Segmentation Annelida (segmented worms) PROTOSTOMES Protostome Mollusca BILATERIA development (snails, clams, squid) ECDYSOZOA Nematoda (roundworms) Cephalization, CNS, coelom Arthropoda Segmentation (insects, spiders, crustaceans) DEUTEROSTOMES DEUTEROSTOMES Radial symmetry Echinodermata (in adults) (sea stars, sand dollars) Deuterostome development Chordata Segmentation (vertebrates, tunicates) © 2014 Pearson Education, Inc. Origin of Multicellularity  Animals are a monophyletic group – All animals have a single common ancestor  Sponges (phylum Porifera) include the two most basal animal lineages – Multicellularity appears to have originated in a sponge-like animal © 2014 Pearson Education, Inc. Figure 33.2 Choanoflagellates Fungi ANIMALIA Choanoflagellates Porifera (sponges) ANIMALIA Multicellularity Ctenophora (comb jellies) Cnidaria (jellyfish, corals, sea anemones) Diploblasty Acoela (acoels) LOPHOTROCHOZOA Rotifera (rotifers) Loss of coelom Platyhelminthes Triploblasty (flatworms) Segmentation Annelida (segmented worms) PROTOSTOMES Protostome Mollusca BILATERIA development (snails, clams, squid) ECDYSOZOA Nematoda (roundworms) Cephalization, CNS, coelom Arthropoda Segmentation (insects, spiders, crustaceans) DEUTEROSTOMES DEUTEROSTOMES Radial symmetry Echinodermata (in adults) (sea stars, sand dollars) Deuterostome development Chordata Segmentation (vertebrates, tunicates) © 2014 Pearson Education, Inc. The Origin of Embryonic Tissue Layers  While sponges have the genetic tool kit needed for cell–cell and cell–ECM adhesion, most do not have complex tissues – Tissues are groups of similar cells that are organized into tightly integrated structural and functional units  Animals other than sponges are divided into two groups based on the number of embryonic tissue layers they have © 2014 Pearson Education, Inc. The Origin of Embryonic Tissue Layers  Diploblasts are animals whose embryos have two types of tissues, or germ layers: 1.The ectoderm (“outside skin”) 2.The endoderm (“inside skin”)  Triploblasts are animals whose embryos have three germ layers: 1.The ectoderm 2.The endoderm 3.The mesoderm (“middle skin”) © 2014 Pearson Education, Inc. The Origin and Diversification of Tissues  Germ layers develop into distinct adult tissues and organs  In triploblasts – Ectoderm gives rise to skin and the nervous system – Endoderm gives rise to the lining of the digestive tract – Mesoderm gives rise to the circulatory system, muscle, and internal structures such as bone and most organs  In general – Ectoderm produces the covering of the © 2014 Pearson Education, Inc. The Origin and Diversification of Tissues  Most cnidarians (which include the jellyfish, corals, sea anemones, and more) and all ctenophores (comb jellies) are diploblastic  All other animals are triploblastic  The evolution of mesoderm was important because it gave rise to the first complex muscle tissue used in movement © 2014 Pearson Education, Inc. Origin of Bilateral Symmetry, Cephalization, and the Nervous System  Body symmetry is a key morphological aspect of an animal’s body plan (a) Radial symmetry(b) Bilateral symmetry Figure 33.5 Cnidarians, Most other animals exhibit ctenophores, bilateral and some sponges symmetry, with a single © 2014 Pearson Education, Inc. plane of symmetry and Homology or Convergent Evolution?  Bilaterians are triploblastic, bilaterally symmetrical animals  The symmetry in bilaterians results from the action of – Hox genes – Regulate development of the anterior– posterior axis – Decapentaplegic (dpp) genes – Regulate development of the dorsal– ventral axis © 2014 Pearson Education, Inc. Origin of the Nervous System  Biologists hypothesize that the evolution of the head and nervous system are tightly linked to the evolution of bilateral symmetry (a) Nerve net: (b) Central nervous system: diffuse neurons in hydra clustered neurons in earthworm Cnidarians, All other animals Ctebophores Ganglia Figure 33.8 © 2014 Pearson Education, Inc. Origin of the Nervous System  The evolution of the CNS coincided with cephalization – Evolution of a head where structures for feeding, sensing the environment, and processing information are concentrated  The cerebral ganglion or brain is located in the head – Large mass of neurons that is responsible for sending and receiving information to and from the body © 2014 Pearson Education, Inc. Origin of the Coelom  The basic bilaterian body shape is a tube within a tube Figure 33.9 Skin and nervous system derived Muscles and Coelom from ectoderm organs derived (cavity lined (Outer tube) from mesoderm with mesoderm) Mouth Gut derived from endoderm (Inner tube) Anus © 2014 Pearson Education, Inc. Origin of the Coelom  A coelom is an enclosed, fluid-filled body cavity between the tubes Provides a space for oxygen and nutrients to circulate Enables the internal organs to move independently of each  Theother coelom likely evolved in the common ancestor of protostomes and deuterostomes © 2014 Pearson Education, Inc. Origin of the Coelom  The coelom creates a container for circulation of oxygen and nutrients, and acts as an efficient hydrostatic skeleton – Allows soft-bodied animals to move even without fins or limbs  The evolution of the coelom gave bilaterally symmetric organisms the ability to move efficiently in search of food © 2014 Pearson Education, Inc. Origin of Protostomes and Deuterostomes  The bilaterally symmetric common ancestor with a CNS, cephalization, and a coelom gave rise to many diverse lineages  There are two subgroups based on embryonic development © 2014 Pearson Education, Inc. Origin of Protostomes and Deuterostomes 1. Protostomes – The mouth develops before the anus – Blocks of mesoderm hollow out to form the coelom – Includes arthropods, mollusks, and segmented worms 2. Deuterostomes – The anus develops before the mouth – Pockets of mesoderm pinch off to form the coelom – Includes chordates and echinoderms © 2014 Pearson Education, Inc. Origin of Protostomes and Deuterostomes  A fundamental split occurred within protostomes, forming two major protostome subgroups: 1.The Lophotrochozoa – Grow by extending the size of their skeletons – Grow continuously when conditions are good – Includes the mollusks, annelids, flatworms, and rotifers 2.The Ecdysozoa – Grow by shedding their external skeletons © 2014 Pearson Education, Inc. Origin of Segmentation  Segmentation is the presence of repeated body structures  A segmented backbone is a defining characteristic of the vertebrates – Includes fish, reptiles, birds, amphibians, and mammals © 2014 Pearson Education, Inc. Origin of Segmentation  Invertebrates, animals that are not vertebrates, - Segmentation occurs in annelids and arthropods - Research suggests that segmentation arose independently in these lineages © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Sensory Organs  Sight  Hearing  Taste/Smell  Touch © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Sensory Organs  Sight  Hearing  Taste/Smell  Touch © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Sensory Organs  Sight  Hearing  Taste/Smell  Touch © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Sensory Organs  Sight  Hearing  Taste/Smell  Touch © 2014 Pearson Education, Inc. Specialized Sensory Abilities  As animals diversified, a wide array of more specialized sensory abilities evolved – Magnetic field – Some animals can detect magnetic fields and use them as a navigation aid – Electric field – Some aquatic predators can detect electrical activity in the muscles of passing prey – Barometric pressure – Some birds can avoid storms by sensing changes in air pressure © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  What animals eat  Detritivores  Herbivores  Carnivores  Omnivores © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  What animals eat  Detritivores  Herbivores  Carnivores  Omnivores © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  What animals eat  Detritivores  Herbivores  Carnivores  Omnivores © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  How Animals Eat  Suspension Feeders:  Deposit Feeders  Fluid Feeders  Mass Feeders © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  How Animals Eat  Suspension Feeders  Deposit Feeders:  Fluid Feeders © 2014 Pearson Education, Inc.  Mass Feeders 33.3 – Diversification Themes  How Animals Eat  Suspension Feeders  Deposit Feeders  Fluid Feeders:  Mass Feeders © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  How Animals Eat  Suspension Feeders  Deposit Feeders  Fluid Feeders  Mass Feeders: © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Movement  Lobe-like limbs:  Jointed limbs  Parapodia  Tube feet  Tentacles © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Movement  Lobe-like limbs  Jointed limbs:  Parapodia  Tube feet © 2014 Pearson Education, Inc.  Tentacles 33.3 – Diversification Themes  Movement  Lobe-like limbs  Jointed limbs  Parapodia:  Tube feet  Tentacles © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Movement  Lobe-like limbs  Jointed limbs  Parapodia  Tube feet:  Tentacles © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Movement  Lobe-like limbs  Jointed limbs  Parapodia  Tube feet  Tentacles: © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Reproductio n  Asexual  What sort of cell division is involved? © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Reproductio n  Sexual  What sort of cell division is involved?  External fertilization © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Reproduction  Sexual  Internal fertilization © 2014 Pearson Education, Inc. 33.3 – Diversification Themes  Reproduction  Embryo development Image: Karen Pulfer Focht Giraffes are viviparous © 2014 Pearson Education, Inc. Life Cycles  Most sexually reproducing animals have diploid- dominant life cycles because the haploid gametes are single celled and short lived – There are, however, exceptions to this general pattern  Perhaps the most spectacular innovation in animal life cycles involves the phenomenon known as metamorphosis  A drastic change from one developmental stage to another © 2014 Pearson Education, Inc.  33.3 – Diversification Themes  Life Cycles Direct Development © 2014 Pearson Education, Inc. Figure 33.14 Indirect Development Diploid (2n) (most animals) EMBRYOGENESIS Haploid (n) N Zygote IO ME AT (2n) TA IZ Larva MO IL (2n) RT RP FE HO Egg (n) Sperm (n) SIS G AM Juvenile ET (2n) O G EN ES TH IS OW GR Adult (2n) © 2014 Pearson Education, Inc.