Animals Chapters 32-35 Exam November 22, 2011
Overview of Animals Chapter 32
General Features of Animals and Evolution of the Body Plan
General Features of Animals Heterotrophs Multicellular No Cell Walls Active Movement Diversity in Form and Habitat Sexual Reproduction Embryonic Development Unique Tissues
Key Evolutionary Developments Evolution of Tissues Evolution of Symmetry Types Evolution of the Body Cavity Evolution of Developmental Patterns Evolution of Segmentation
Tissues Tissues allow for Specialization and Differentiation Only the Parazoa do not have specialized tissues Even the Parazoa have cell-level specialization
Symmetry Parazoa are again the exception. Radial Bilateral
Body Cavity Most animals produce 3 types of tissue Bilaterally Symmetrical bodies follow three basic plans
Circulatory System As body sizes increases the need to move fluid becomes active and we see the evolution of a circulatory system Open Circulatory System Closed Circulatory System
Spiralians vs. Deuterstomes
Traditional Taxonomy of Animals
Parazoa vs. Eumetazoa Traditional taxonomy differentiates between the near animals (Parazoa) and true animals (Metazoa) Parazoa lack true differentiated tissue and symmetry
Molecular vs. Morphology On many groupings traditional morphology methods agree with molecular data. Morphology taxonomy is based on the presence or absence of the coelom. Molecular taxonomy is based on the genetics of differentiation End Result: While there is concurrence, molecular data shows that the coelom developed a number of times.
Roots of the Animal Family Tree
Where did we come from? Multinucleate Hypothesis Colonial Flagellate Hypothesis Molecular Data supports the Colonial model.
Noncoelomate Invertebrates Chapter 33
The New Invertebrate Phylogeny
Parazoa Animals That Lack Specialized Tissues
Dominant group of the Parazoa These are the Sponges Lacking true symmetry or tissues While the adults are sessile, the larval stage is motile. Porifera
Cell Types
Look Familiar?
Eumetazoa Animals with True Tissues
Phylum Cnidaria Distinct Specialized Tissues Mostly Marine in Nature No Organs Primitive Sensory System
Cnidaria Body Plans Polyp vs. Medusa Mesoglea glue material between the epidermis and gastrodermis Gastrovascular Cavity
Cnidaria Specialized Tissues
Cnidaria Life Cycles Life Cycles vary by species, but can include both a polyp and medusa stage or only one. Individuals are diploid tissue and sexual haploid gametes are produced, sexes can separate. The diploid zygote develops into a larval planula Asexual reproduction is also possible.
Nematocysts Defining characteristic of the phylum Used to incapacitate and acquire food Expulsion is one of the fastest known biological processes.
Major Groups of Cnidaria Class Anthozoa Sea Anemone and Corals Class Cubozoa Box Jellies Class Hydrazoa Hydroids Class Scyphozoa Jellyfish Class Staurozoa Star Jellies You should learn a defining characteristic of each
Phylum Ctenophora Surface similarity to the Cnidaria is not borne out. They do not possess nematocysts and possess an anal pore. They possess colloblasts for prey capture They possess mesoderm tissue
The Bilaterian Acoelomates
Phylum Platyhelminthes Flatworms Incomplete Guts Complex systems Cephalized
Platyhelminthes Groups Class Turbellaria* Free-Living Flatworms Subphylum Neodermata Parasites Possess a Neodermis and lack Eyepores Comprised of two Subgroups Trematodes Flukes Cercomeromorpha - Tapeworms
Schistosoma Life Cycle
Tapeworms Body divided into three sections Scolex Neck Proglottids No digestive systems
Acoel Flatworms Distinct from Flatworms Convergent Appearance Lack digestive cavity Primitive nervous system Uncertain position
Phylum Cycliophora Near Microscopic Live in the mouthparts of Claw Lobsters Sexual cycle is linked to Lobster molt
The Pseudocoelomates
Pseudocoelm A body cavity isolated from the exterior environment Serves as a hydrostatic skeleton Serves as a circulatory system Evolved numerous times
Phylum Nematoda Roundworms Possess a cuticle that they molt Developed digestive and reproductive systems Lack circular muscles
Nematoda Anatomy
Nematoda Life Cycle Most are gonochoric and exhibit sexual dimorphism Development is often indirect (larval to adult) Eutely (a precise number of cells) is common and allows for determination of cellular development in some species.
Nematoda Diseases
Phylum Rotifera
Coelomate Invertebrates Chapter 34
Phylum Mollusca
Phylum Mollusca
Mollusca Characteristics Extremely varied in body plan and appearance. Coelom is reduced and the role replaced by a shell in many. Highly efficient gas exchange system Most mollusks possess a radula Most posses open circulatory systems
Class Polyplacophora: Chitons Marine species Covered in shell plates Grazing animals Modified foot that serves as an anchor against predators.
Class Gastropoda Snails and Slugs Most adults are not bilaterally symmetrical due to torsion. Numerous predatory adaptations Evolution of a primitive lung.
Class Bivalvia Clams and such No radula or cephalization Extremely agile while digging or swimming Two shells
Class Cephalopoda Octopuses, squids, and nautiluses Highly divergent and specialized body plan Largest relative brain sizes of invertebrates Direct development Highly advanced eyes
Phylum Annelida
Annelida Characteristics Body Segmentation Cephalized with developed brains Head and Tail develop first, then the internal segments develop Segments are separated by septa, but communicate between the sections. Most possess chaetae Circulatory system is closed, but excretory system is segmented.
Possess paired fleshy parapodia Class Polychaeta
Class Clitellata Earthworms and leeches Named for the clitellum, a thicken saddle around the worm.
Hirudo medicinalis
The Lophophorates Bryozoa and Brachiopoda
Lophophore Defining characteristic of these Phyla A circular or U-shaped ridge around the mouth bearing one or two rows of ciliated tentacles into which the coelom extends.
Phylum Bryozoa Exclusively colonial Specialized members within the colony Can produce structures much like coral.
Phylum Brachiopoda Possess a U-shaped digestive system Solitary animals Possess hardened mantles or chitinous sheaths.
Phylum Anthropoda
Key Features of Arthropoda Segmentation Exoskeleton Jointed Appendages Circulatory System Nervous System (central and diffuse) Respiratory System Excretory Systems
Segmentation, Exoskeleton and Joints
Internals
Class Chelicerata Spiders, mites, ticks, and horseshoe crabs, etc. Defined by the chelicerae, pedipalps and four pairs of walking legs Two body segments
Class Crustacea Crabs, Lobsters, Pill Bugs, etc. 2 pairs of antennae, 3 pairs of feeding appendages, and various legs They have appendages on the abdomen.
Class Hexapoda Mandibles Three body regions One pair of antennae Thorax has three segments, each with a pair of legs Wings are derived from outgrowths, not legs
Class Myriapoda Having a myriad of legs Mandibles A head with various segments Each segment contains a pair of legs. Segments can be added as they grow.
Phylum Echinodermata
Characteristics Adults are pentaradially symmetrical, but larval forms are bilaterally symmetrical They possess an endoskeleton (the things you usually buy at gift shops) Water-Vascular System Regeneration
Anatomy
Classes Asteroidea Holothuroidea Echinoidea Crinoidea Ophiuroidea
Vertebrates Chapter 35
The Chordates and Nonvertebrate Chordates
Fishes
Amphibians
Reptiles
Birds
Mammals
Evolution of Primates