BIO REV

• Zoology is also known as animal science is the branch of biology devoted to the study of animal life.
• Zoology is the branch of biology that 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

  • (which means “arrangement law”) is the science of classifying organisms to construct internationally shared classification systems with each organism placed into more and more inclusive groupings.
• Taxonomic Classification System – also called the Linnaean system after its inventor, Carolus Linnaeus, a Swedish botanist, zoologist, and physician, which uses a hierarchical model.
• Three Domains of Life

  • Eukaryota
  • Bacteria
  • Archaea 
• Domain => Kingdom => Phylum => Class => Order => Family => Genus => Species
• Binomial Nomenclature

  1. Naming of organisms using 2 names.
  2. It consist of 2 epithets (words) (Genus and Species)
  3. It was first introduced by Linnaeus in 1751.
• Kingdom Animalia, also known as Metazoa
• Asexual reproduction produces genetically identical copies (ex. clones) while sexual reproduction produces genetically unique offspring.
• Budding (Asexual reproduction)

  A very common type of asexual reproduction especially in colonial animals. In budding 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.
• Regeneration

  This process is most commonly used not just as a form of reproduction but also to replace missing or damaged parts. Some organisms have great powers of regeneration while others can only regenerate simple cells and tissues. In other animals, such as lizards and arthropods, tails or whole limbs can be replaced. Starfish can regenerate new “arms” when one is broken off and sometimes a single arm can regenerate an entire starfish.
• Polyembryony

  A type of asexual reproduction in which two or more embryos (result of sexual reproduction) develop from a single fertilized egg, forming clones. This is a common phenomenon which occurs regularly in the nine-banded armadillo, which usually gives birth to four identical young.
• Parthenogenesis

  Known as the ‘virgin birth’ which occurs in non-human animals, both vertebrates and invertebrates. In these cases the unfertilized egg is able to develop even though it has not been fertilized by a sperm. Most rotifers (wheel animals), brine shrimp and some social insects such as ants regularly reproduce this way. Some higher animals such as fish and frogs can also sometimes reproduce in this way.
• Monoecious Animals (Hermaphrodites):

  Those containing both male and female reproductive organs. About 15% of animals, especially those that are sessile (non-motile) or parasitic, tend to be hermaphrodites.
• Dioecious Animals:

  These are organisms that produce either male or female reproductive organs and gametes but never both at the same time.
• Protandry and protogyny is the ability in some animals to switch their sex based on environmental cues such as changes in temperature or leadership in a colony.
• Animals develop first as male and then switch to female (protandry)
• the individuals develop first as female and then switch to male (protogyny)
• Sexual Dimorphism: 

  Sometimes it is impossible to distinguish the male from the female of a species by outward appearance. In other dioecious animals the males and females are not identical, thus showing dimorphism. For example, in most invertebrates the male is usually smaller than the female, while in vertebrates the female is usually the smaller one. In addition to size, dimorphism may also result in differences in structures and color between genders. In birds the male is usually more brightly colored.
• Phylum Porifera

  • from Latin porus ‘pore’ + -fer ‘bearing’.
• Phylum Porifera

  • most primitive animal phylum
• Phylum Porifera

  • no true tissues
• Phylum Porifera

  • simple body plan with pores and water channels
• Phylum Porifera

  Ex. Sponges
• How do sponges eat?

  1. The water enters the sponge through its pores.
  2. Inside the sponge, cells called collar cells, which filters / strains the food and microorganisms from the water.
  3. Then the water flows into the central cavity and out the top of the sponge through a hole called osculum.
• Sponges sexually reproduce through the process of synchronous spawning.
• Sponges also reproduce asexually by the process of budding.
• Phylum Cnidaria

  • Greek word “cnidos”, which means “stinging”
• Phylum Cnidaria

  • they are invertebrates
• Phylum Cnidaria

  • has two true tissue layers
• Phylum Cnidaria

  • gastrovascular cavity, no anus but with mouth
• Phylum Cnidaria

  • They can be in the form of Medusa (mobile life stage of cnidaria), or Polyp (sessile or immobile stage of cnidaria; fixed)
• Phylum Cnidaria

  • hydrostatic skeleton
• Phylum Cnidaria

  • nerve net and simple receptors
• Phylum Cnidaria

  • Cnidocytes (stinging cells) which contains organelles called nematocysts (stingers) for capturing prey
• Phylum Cnidaria

  • Example: Jellyfish, sea anemones
• Phylum Cnidaria

  Class Hydrozoa

  Class Scyphozoa (Jellyfish)

  Class Cubozoa (Box Jellyfish)

  Class Anthozoa (Sea Anemones and Corals)
• Phylum Ctenophora

  • came from the Greek words ‘kteis / kten’ which means comb + ‘pherein’ which means to bear
• Phylum Ctenophora

  • have cilia to help them move