BIO 1306 Exam VI Lectures Notes

Fungi

  • Essential for terrestrial ecosystems.
  • Heterotrophs that feed by absorption.
  • Cell walls contain chitin, preventing explosion from water absorption.
  • Morphology: Yeast (single-celled, moist environments) and Filamentous (multicellular, hyphae, mycelium).
  • Roles: Decomposers (nutrient cycling), Parasites (negative symbiosis), and Mutualists (positive symbiosis).
  • Decomposers break down cellulose and lignin.
  • Pathogens: 30% of fungi, mostly plant parasites (e.g., smuts, rusts, ergots).
  • Mutualists include mycorrhizal fungi (plant roots) and endophytes (plant leaves).
  • Lichens: fungi + algae or cyanobacteria, sensitive to pollution.
  • Practical uses: Bioremediation, food (mushrooms, yeast), medications (antibiotics).
  • Five major fungal groups: Chytrids, Zygomycetes, Glomeromycetes, Ascomycetes, and Basidiomycetes.
    • Chytrids: flagellate zoospores, some kill amphibians.
    • Zygomycetes: fast-growing molds.
    • Glomeromycetes: arbuscular mycorrhizal fungi.
    • Ascomycetes: sac fungi, diverse, include yeast and lichens.
    • Basidiomycetes: club fungi, decompose wood.

Animals

  • Multicellular, heterotrophic eukaryotes with tissues from embryonic layers.
  • Key events: Cambrian Explosion (body plans), Permian Extinction, Cretaceous Extinction.
  • Metazoa: Porifera (sponges) are basal taxon.
  • Ediacaran Period: soft-bodied organisms, invertebrates appeared.
  • Invertebrates: animals without a backbone, 95% of species.

Porifera (Sponges)

  • Sedentary, suspension feeders.
  • Choanocytes create water current; amoebocytes digest food.

Cnidaria

  • Oldest eumetazoan lineage with true tissues.
  • Radial symmetry, diploblastic.
  • Mobile medusa and sessile polyp forms.
  • Carnivores with nematocytes (stingers).

Bilateria

  • Most groups appeared during Cambrian explosion.

Mollusca

  • Soft-bodied animals with muscular foot.
  • Gastropods (snails), Bivalves (clams), Cephalopods (squids).
  • Threatened by habitat loss.

Arthropoda

  • Most diverse and abundant animals.
  • Key features: body segmentation, exoskeleton (chitin), jointed appendages.
  • Arachnids, crustaceans, insects.
  • Colonization of land: insects were the first animals.
  • Insects success due to flight and diversification of mouthparts.
  • Complete metamorphosis: larva, pupa, adult, eggs.

Chordata

  • Four key characteristics: notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail.
    • Notochord: skeletal support.
    • Dorsal hollow nerve cord: brain and spinal cord.
    • Pharyngeal slits: suspension feeding/gas exchange.
    • Post-anal tail: propulsion.
  • Cephalochordata (lancelets): all 4 characteristics as adults.
  • Gnathostomes: vertebrates with jaws.

Devonian Period (Age of Fishes)

  • Fish diversified, jaws and lungs developed.

Chondrichthyes

  • Cartilaginous fish (sharks, rays).

Actinopterygians

  • Ray-finned fish (ossified skeleton, operculum, air bladder).

Sarcopterygians

  • Lobe-finned fish (lungfish - gills and lungs).

Tetrapods

  • Gnathostomes with limbs and digits.
  • Tiktaalik: “fishapod” missing link.

Carboniferous period

  • Age of Amphibians, dominated swampy areas.

Amphibians

  • Rely on water for reproduction.
  • Frogs, salamanders, caecilians.

Amniotes

  • Tetrapods with terrestrially adapted eggs.
  • Reptiles, birds, mammals.

Reptiles

  • Scales, amniotic egg.
  • Ectothermic (absorb external heat).

Birds

  • Endothermic (maintain body temp by metabolism).
  • Reptilian anatomy modified for flight (hollow bones, feathers, air sacs).

Cretaceous Mass Extinction

  • Asteroid impact led to extinction of dinosaurs.

Cenozoic Era

  • Age of Mammals, adaptive radiation.

Mammals

  • Hair, mammary glands, endothermic.
  • Monotremes (lay eggs), Marsupials (pouch), Eutherians (placenta).

Primates

  • Forward-looking eyes, grasping hands/feet.

Human characteristics

  • Upright posture, bipedal locomotion, larger brains.