Zoology

• Zoology


  Also known as animal science, the branch of biology devoted to the study of animal life
• Zoology


  • Studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems

  
• Taxonomy


  The science of classifying organisms to construct internationally shared classification systems with each organism placed into more and more inclusive groupings
• Linnaean system


  The taxonomic classification system, also called the Linnaean system, after its inventor, Carlolus Linnaeus, a Swedish botanist, zoologist, and physician, uses a hierarchical model
• Kingdom Animalia, also known as Metazoa, comprises a broad range of animal species, from tiny parasitic nematodes and microscopic invertebrates to the largest of mammals -- the blue whale

  
• The exact number of members of kingdom Animalia is unknown and difficult to guess; there are over one million estimated insects alone
• Kingdom Animalia


  • The largest kingdom in terms of the number of different kinds of species
  • Animals are represented by a very diverse array of sizes, shapes and forms from very simple to extremely complex, including the "human animal"
  • All animals are multicellular heterotrophs
  • Most animals have cells differentiated into highly complex tissues and organs

  
• Plants vs Animals


  • Whereas plants had tissue systems and relatively simple vegetative and reproductive organs, animals have complex tissues forming organs and elaborate organ systems
  • The greater specialization of cells and tissues increases the efficiency by which animals can carry out life's basic processes and allows for almost limitless opportunities for evolutionary variations and adaptations to numerous kinds of habitats and environmental conditions
• There are about 36 distinct phyla within the animal kingdom, many of these phyla contain only one or a few species, yet differ enough from other animals that they are given their own distinct "category"

  
• Some of the largest, most common, or most recognizable groups of animals, categorized roughly in order of increasing complexity

  • Sponges
  • Vertebrates

  
• Members of the Animal Kingdom

  • Multicellular, eukaryotic organisms
  • Cells with no cell wall or chloroplasts and more mitochondria
  • Cells differentiated into complex tissues: epithelial, connective, muscular, nervous
  • Tissues differentiated into complex organs and organ systems
  • Heterotrophic nutrition (herbivores, carnivores, saprobes)
  • Much more active and have a much higher metabolism than members of any other kingdom
  • Require free oxygen for energy production
  • Extra energy usually stored as fats & oils
  • Most are motile at some point in their life cycle
  • Reproduce both sexually and asexually, animals show a great diversity in kinds of reproduction, some with well developed alternation of generations
  • Most have a relatively complex developmental phase including an embryonic or a larval stage as they progress from zygote to adult
  • Most have fairly elaborate behaviors to enhance their survival within their habitat
• Asexual reproduction


  Produces genetically identical copies (ie. clones)
• Sexual reproduction


  Produces genetically unique offspring
• Types of asexual reproduction in animals

  • Budding
  • Fragmentation
  • Polyembryony
  • Regeneration
  • Parthenogenesis
• Budding


  A very common type of asexual reproduction especially in colonial animals, where a new offspring begins as an outgrowth of the parent and may either remain attached and form a colony or break away and begin an independent life
• Fragmentation


  Some animals spontaneously break into many separate pieces which then regrow into a complete animal
• Polyembryony


  A type of asexual reproduction in which the embryo or larva (resulting from sexual reproduction) then clones itself into separate individuals. This allows a single egg to produce 100's of potential offspring and enhances chances that at least a few will be able to find a new host to complete their life cycle
• Regeneration


  The process of replacing missing or damaged parts, where some organisms have great powers of regeneration while others can only regenerate simple cells and tissues
• Parthenogenesis


  Also known as 'virgin birth', this process only regularly occurs in nonhuman animals, both vertebrates and invertebrates, where the unfertilized egg is able to develop even though it has not been fertilized by a sperm
• Types of sexual reproduction in animals

  • Monoecious (hermaphrodites)
  • Dioecious
  • Protandry
  • Sexual dimorphism
• Monoecious (hermaphrodites)


  Organisms containing both male and female reproductive organs
• Dioecious


  Organisms that produce either male or female reproductive organs and gametes but never both at the same time
• Protandry


  The ability in some animals to switch their sex based on environmental cues such as changes in temperature, where they develop first as male and then switch to female
• Sexual dimorphism


  When the male and female of a species differ in appearance, such as size or coloration
• Major animal phyla


  • Porifera (sponges)
  • Cnidaria (jellyfish and corals)

  
• Porifera (sponges)


  • Most primitive animal phylum, with no true tissues and a simple body plan with pores and water channels
• Porifera cell types and structures

  • Pinacocytes (flattened epithelial cells)
  • Choanocytes (collar cells that create water currents)
  • Mesophyll (gelatinous matrix with scattered cells)
  • Spicules (made of calcium carbonate, silica or fibers of spongin)
  • Gemmules (internal asexual buds in freshwater species)
• Porifera body organization (canal systems)

  • Ascon body type
  • Sycon body type
  • Leucon body type
• Porifera classes


  • Demospongiae (commercial sponges)
  • Calcarea (calcareous sponges)
  • Hexactinellida (glass sponges)
• Cnidaria


  • Have two true tissue layers (germ layers), alternation of generations between polyp and medusa forms, many colonial species, gastrovascular cavity with mouth but no anus, hydrostatic skeleton, nerve net and simple receptors, cnidocytes with nematocysts for capturing prey
• Cnidaria cell and tissue types

  • Epitheliomuscular cells (form epidermis)
  • Nutritive-muscular cells (form gastrodermis lining gastrovascular cavity)
  • Mesoglea (gelatinous layer between tissue layers)
  • Cnidocytes (stinging cells containing nematocysts)
• Cnidaria body organization


  • Polyp form (saclike with tentacles)
  • Medusa form (umbrella-like with tentacles around edge)
  • Colonial forms with specialized polyps

  
• Cnidaria classes


  • Hydrozoa
  • Scyphozoa (jellyfish)
  • Cubozoa
  • Anthozoa
• Cnidaria


  • Mouth, no anus
  • Hydrostatic skeleton
  • Nerve net and simple receptors
  • Cnidocytes with nematocysts for capturing prey
• Cnidaria


  • Jellyfish and corals
• Epitheliomuscular cells


  Form epidermis
• Nutritive-muscular cells


  Form gastrodermis which lines GVC
• Mesoglea


  Gelatinous layer between the two tissue layers above
• Cnidocytes (stinging cells)


  Contain harpoon-like nematocysts
• Body Organization of Cnidaria

  • Polyp -saclike with tentacles
  • Medusa -umbrella-like with tentacles around edge
  • Colonial forms -may have polyps specialized for feeding or reproduction