330

• How many species are extant?

  >70 000
• When did species diversity peaked?

  mid-Miocene (14-12 MYA)
• In non-amniotes, embryos are enclosed by maternally-produced membranes. Include: Jawed fishes, Jawless fishes and Amphibians.
• In amniotes, embryos have 3 membranes (amnion, chorion, allantois) that come from the embryos themselves. Include: Sauropsids and Synapsids.
• Sauropsids: turtle, lizards, snakes, alligators, crocodiles, birds.
• Synapsids: mammals w/ placenta.
• Around when did veretebrate life begin?

  540 MYA
• What influenced the evolution of vertebrates?

  continental shifts that resulted in global climate changes that led to the creation, alteration or disappearance of habitats--> adapted to specific environmental conditions.
• What happened during the Paleozoic Era?

  Pangaea was located near Equator.
• The evolution of vertebrates followed different trajectories w/ what?

  Changing climates: Northern and Southern hemisphere were temperate rather than tropical.
• Goals of scientific naming of species?

  1. Uniqueness (no 2 species can share the same name)
  2. Universality (everyone agrees to use the same name)
  3. Stability (species name cannot be changed once it is properly named)
• Reasons for change in species' names?

  1. 1 became 2 or 3 species
  2. species is not distinct as was thought
  3. species misplaced in genus
  4. name already
  5. principle of priority- trademark
• Phylogenetic systematics- a method of classifying organisms (both extant and extinct) and understanding their evolutionary relationships based on shared ancestry. It uses a variety of data sources including morphological, molecular, and behavioural data.
• Cladistics – a specific method of classifying organisms within phylogenetic systematics that is characterized by its use of shared derived characteristics. It places a strong emphasis on monophyly (a group of organisms that includes an ancestor and all of its descendants) and parsimony (the simplest explanation for observed character state changes).
• what is a group of organisms that have a single evolutionary origin and include all descendants and its common ancestor?

  Clade
• What is a taxon that includes the common ancestor and some, but not all, of its descendants?

  Paraphyly
• What is a monophyletic lineage most closely related to the monophyletic lineage being discussed?

  Sister group
• Topology is the arrangement of branches and taxa on a tree diagram.
• Which is same and different?

  A) Same

  B) Different

  
• Apomorphy vs synapomorphy?

  Apomorphy: a derived trait that is uniquely evolved to a particular group or species. Synapomorphy: a derived trait shared by a group of organisms, indicating their common ancestry.
• Pleisomorphies?


  organisms within a clade that share characters that they have inherited from their ancestors. Plesiomorphic traits tell us nothing about the degree of relatedness among taxa.
• Outgroup – a reference group when building phylogenetic trees that is known to be related to the organisms under investigation (i.e., ingroup) but is less closely related to any member of the ingroup than the ingroup members are to each other. Helps with determining ancestral traits.
• What is the principle of Parsimony?

  “Any change in a structure is an unlikely event, so the most plausible phylogeny is the one requiring the fewest number of changes”
• What is Homoplasy ?

  similarities in characters that are not indicative of a common ancestry
• Why are phylogenies considered hypotheses?

  Falsified as new data comes in

  Need good outgroup --> character shared or ancestral
• Metezoans are multicellular heterotrophs (feed other organisms) and motile mostly.
• Sponges are the most basal metazoan
• What are the 4 synapomorphies of phylum chordates?

  1. notochord
  2. Dorsal hollow-neural tube
  3. Segmented postanal tail
  4. Endostyle- ciliated glandular groove on the floor of the pharynx -secretes mucus for trapping food particles (generally homologous w/ the vertebrate thyroid gland)
• What are the 3 subphyla of chordates?

  vertebrates, urochordates, cephalochordates
• Which subphyla is a sister group to vertebrates?

  urochordates
• What are the 2 types of urochordates?

  appendicular tunicates (motile, pelagic, filter-feeding)

  Ascidian tunicates (motile but non-feeding larvae that metamorphose to sessile adults)
• What filter food particles from seawater?

  urochordates
• what subphyla has most adults sedentary?

  urochorates
• Urochordates do not retain all four chordates synapomorphies.

  False they do.
• What feature distinguishes vertebrates?

  Cranium

  prominent head w/ complex sense organs

  neural crest

  Large brains having 3 parts

  Complex endocrine organs

  Muscularized gut tube

  Multichambered heart

  mineralized tissues

  Gills
• What are gills efficient for and what are they derived from?

  respiration and from endoderm.
• What is a neural crest?

  unique germ layer that forms many new structures (eg head)
• What are mineralized tissues?

  deposists of minerals (Ca) that creates rigid structures (calcified cartilage, bone, enamel, dentine)
• Why do we observe an increased body size and activity in vertebrates?

  need organ systems that carry out physiological processes at a greater rate

  evolution towards larger head, muscular pharynx, bigger brain, sensory system

  Need muscles and skeletons (mobility)
• Ectoderm – outermost layer, forms the superficial layers of skin (epidermis), linings of most anterior and posterior parts of the digestive tract, and most of the nervous system.