concepts

• evolution produces biodiversity and adaptations to survive in different environments
• charles Darwin's theories in five parts:

  1. perpetual change (the fossil record)
  2. descent with modification (common descent)
  3. multiplication of species
  4. gradualism (slow change)
  5. natural selection
• archaeopteryx is a fossil bird from jurassic period with bird features and reptilian features
• speciation begins as populations are isolated from each other, and their allele for frequencies diverge
• reproductive isolation usually arise as a by-product of geographic separation
• natural selection is the cause of adaptation
• natural selection is unequal reproduction leads to favorable traits increasing frequency
• Homologies are hierarchically arranged (close relatives share many traits, distant relatives share fewer traits)
• ecdysozoa are periodically molted cuticle
• homologies could be used to reconstruct phylogenetic relationships
• Taxonomy and Phylogeny is the descent with modification and extinction lead to discrete taxa
• Phylogeny is the "tree of life" depicting evolutionary relationships at any taxonomic level (or all of life)
• Carolus Linnaeus (father of taxonomy) developed a binomial system and a hierarchical ranking scheme
• The species is the fundamental taxonomic unit (leaves on the tree of life)
• Animal architecture?

  -body symmetry

  -number of cell layers
• most animals are coelomates (possess a coelom)
• acoelomates don't have a coelom (flatworms)
• Early animal development have a vegetal (nutritive organs, digestive system) and animal (everything else) poles
• as cells divide, a blastocoel may form (hollow ball of cells)
• As cells divide, a blastocoel may form and an embryo may develop into gastrula causing gastrulation (investigation)
• radial cleavage include chordates, echinodermata, and cnidaria
• spiral cleave includes mollusks, annelids, and arthropods
• in some animals(ex. mollusks and annelids), all mesoderm descendants from the 4d micromere
• coelom forms via schizocoely: mesodermal mass hallows out(splits)
• coelom also forms via enterocoely: formation via mesoderm outpocketing from the embryonic gut
• some traits go together like spiral determinate cleavage with protostomy and schizocoely
• some traits go together like radial indeterminate cleavage with deuterostome and enterocoely
• spongocytes/sclerocytes

  • secrete collagens (spongin)/spicules
  • amoeboid cells
• amoeboid cells called archaeocytes: can differentiate into other cell types (including eggs)
• for sponges, choanocytes pump water through in order to grab food
• sponges can reproduce by sexual reproduction, most are hermaphroditic (monoecious: both male and female (can alternate))
• A synapomorphy that cnidarians contains cnidae (stinging organelles)
• Cnidarians do NOT have a coelom, due to not having a mesoderm layer
• polyps are found in the benthos and are sessile. They also often clone
• ramets means body, and genets means a specific gene (genotype)
• medusae are mainly pelagic "jellyfish", which reproduce sexaully
• cnidae are intracellular organelles used for feeding or defense
• the main type of cnida is called a nematocyst (contains toxins;typically neurotoxins)
• scyphozoa are most jellies
• scyphozoa planula may develop into a benthic polyp stage called a scyphistoma