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.