Bio II Lab Study Guide: Fungi, Animal Evolution, and Mammalian Ecology

Unit 1. Fungi, Opisthokonta, and Early Animal Evolution

Clade Opisthokonta

The Opisthokonta is a clade that includes fungi, animals, and their closest protistan relatives. Members are united by a rearward-facing flagellum in their motile cells, which is evolutionarily significant as it distinguishes them from other eukaryotic groups.

• Rearward-facing flagellum: Allows efficient movement and is a synapomorphy for the clade.

• Examples: Fungi, animals, and choanoflagellates.

Fungal Structure and Classification

Fungi are classified based on their reproductive structures and body organization.

• Hyphae: Thread-like filaments forming the basic structural unit of fungi.

• Mycelium: A network of hyphae, forming the main body of the fungus.

• Reproductive structures: Used to classify fungal phyla (e.g., ascus in Ascomycota, basidium in Basidiomycota).

Major Fungal Phyla

• Ascomycota: Sexual spores produced in an ascus; examples include yeasts and morels.

• Basidiomycota: Sexual spores produced on a basidium; examples include mushrooms and puffballs.

• Mucoromycota: Sexual structures are zygosporangia; examples include bread molds.

Fungal Mutualisms

Fungi form mutualistic relationships with other organisms.

• Mycorrhizae: Symbiotic association between fungi and plant roots, enhancing nutrient uptake.

• Lichens: Mutualism between fungi and photosynthetic partners (algae or cyanobacteria).

• Lichen body forms: Crustose (crust-like), Foliose (leaf-like), Fruticose (shrubby).

Animal Evolution: Parazoa vs. Eumetazoa

Animals are divided into Parazoa (lacking true tissues, e.g., sponges) and Eumetazoa (having true tissues).

• Sponges: Lack true tissues; possess specialized cells like choanocytes (feeding cells), ostia (pores), and oscula (excurrent openings).

• Water flow: Supports sponge feeding by drawing water through ostia, filtering food via choanocytes, and expelling through oscula.

Cnidaria vs. Ctenophora

Both are early-diverging animal phyla, but differ in key features.

• Cnidaria: Possess nematocysts (stinging cells); includes jellyfish, corals, sea anemones.

• Ctenophora: Lack nematocysts; have comb rows for movement.

Bilateria: Triploblasty, Bilateral Symmetry, and Cephalization

Bilaterians are animals with three germ layers (triploblastic), bilateral symmetry, and cephalization (concentration of sensory organs at the head).

• Triploblasty: Three germ layers: ectoderm, mesoderm, endoderm.

• Bilateral symmetry: Body plan with left and right sides.

• Cephalization: Evolution of a head region.

Corals and Sea Anemones (Anthozoa)

Anthozoa includes corals and sea anemones, characterized by the polyp body form.

• Polyp form: Sessile, cylindrical body with tentacles.

Earthworm Anatomy (Phylum Annelida)

Earthworms are segmented worms in phylum Annelida.

• Clitellum: Thickened, glandular region involved in reproduction.

• Pharynx, crop, gizzard: Digestive organs; pharynx (swallowing), crop (storage), gizzard (grinding).

Unit 2. Lophotrochozoa

Platyhelminthes (Flatworms)

Flatworms are acoelomate (no body cavity), have incomplete digestive systems, and exhibit negative phototaxis (move away from light).

• Acoelomate: No body cavity between digestive tract and body wall.

• Negative phototaxis: Movement away from light, seen in planarians.

Tapeworm Anatomy

• Scolex: Attachment organ at anterior end.

• Gravid proglottids: Segments containing mature eggs.

Rotifers

• Corona: Ciliated structure for feeding.

• Mastax: Muscular pharynx for grinding food.

Annelid Segmentation

• Septa: Internal partitions between segments.

• Setae: Bristles aiding movement.

Molluscan Body Plan

• Mantle: Secretes shell.

• Visceral mass: Contains internal organs.

• Muscular foot: Used for movement.

Gastropod Torsion and Cephalopod Arms

• Torsion: 180-degree twisting of body in gastropods.

• Cephalopod arms/tentacles: Derived from the foot.

Squid Anatomy and Adaptations

• Pen: Reduced internal shell.

• Chromatophores: Pigment cells for camouflage and communication.

• Key structures: Gills, siphon, mantle, ink sac, hearts.

Molluscan Classes

• Gastropoda: Snails, slugs.

• Bivalvia: Clams, oysters.

• Cephalopoda: Squid, octopus.

• Polyplacophora: Chitons.

Unit 3. Ecdysozoa

Ecdysis and Ecdysozoans

Ecdysis is the process of molting the exoskeleton, uniting the Ecdysozoa clade.

• Ecdysozoa: Includes arthropods and nematodes.

Arthropod Body Plan

• 'Jointed feet': Refers to jointed appendages.

• Body regions: Head, thorax, abdomen; cephalothorax in some groups.

Major Arthropod Groups

• Chelicerata: Spiders, scorpions, horseshoe crabs; possess chelicerae.

• Hexapoda: Insects; three body regions, six legs.

• Crustacea: Crabs, crayfish; two pairs of antennae.

• Myriapoda: Centipedes, millipedes; many body segments.

Arthropod Anatomy

• Chelicerae: Feeding appendages in chelicerates.

• Merostomata: Subclass including horseshoe crabs.

• Gastric mill: Grinding organ in crayfish.

• Spiracles: Respiratory openings in insects.

• Centipedes vs. Millipedes: Centipedes have one pair of legs per segment (predatory), millipedes have two pairs (detritivores).

Nematoda vs. Annelida

• Nematoda: Unsegmented, pseudocoelomate.

• Annelida: Segmented, true coelom.

External Anatomy: Horseshoe Crab and Crayfish

• Horseshoe crab: Telson (tail spine), chelicerae, book gills, walking legs; males and females distinguished by size and appendages.

• Crayfish: Cheliped (claw), walking legs, carapace, swimmerets, uropods.

Unit 4. Deuterostomia and Chordates

Deuterostome Development

• Blastopore: Becomes the anus in deuterostomes.

Echinoderm Body Plan

• Pentaradial symmetry: Five-part radial symmetry in adults.

• Water vascular system: Hydraulic system for movement and feeding.

• Water flow: Enters via madreporite, travels through canals.

• Aristotle's lantern: Jaw-like structure in sea urchins.

Chordate Synapomorphies

• Notochord: Flexible rod for support.

• Dorsal hollow nerve cord: Central nervous system precursor.

• Pharyngeal slits: Openings in the pharynx.

• Post-anal tail: Tail extending beyond anus.

Vertebrates and Cephalochordates

• Vertebral column: Replaces notochord in vertebrates.

• Lancelets: Cephalochordates, retain all four chordate traits.

Amniotic Egg and Vertebrate Classes

• Amniotic egg: Adaptation for terrestrial life; contains membranes for protection and nourishment.

• Vertebrate classes: Chondrichthyes (cartilaginous fish), Actinopterygii (ray-finned fish), Sarcopterygii (lobe-finned fish).

Unit 5. Mammalian Adaptations and Ecology

Mammalian Features

• Mammary glands: Nutritive feature defining mammals.

• Heterodont dentition: Different types of teeth for specialized functions.

• Carnassial teeth: Adapted for shearing flesh in carnivores.

• Binocular vision: Forward-facing eyes for depth perception.

Ecological Terms and Relationships

• Native species: Occur naturally in a region.

• Endemic species: Restricted to a specific area.

• Invasive species: Non-native, cause ecological harm.

• Parasitism: One organism benefits, other is harmed (e.g., tapeworms).

• Mutualism: Both organisms benefit (e.g., mycorrhizae).

• Commensalism: One benefits, other unaffected (e.g., mangrove-oyster).

• Keystone species: Disproportionately important to ecosystem stability.

• Habitat: Physical environment where species lives.

• Range: Geographic area where species is found.

Taxonomic Identification and Ecological Interpretation

• Oysters: Mollusks, class Bivalvia; example of commensalism in mangrove-oyster relationship.

High-Yield Vocabulary Table

The following table summarizes key vocabulary and their definitions:

Term	Definition
Opisthokonta	Clade including fungi and animals, united by rearward flagellum
Hyphae	Filamentous structures in fungi
Mycelium	Network of hyphae
Ascus	Sac-like structure producing spores in Ascomycota
Basidium	Club-shaped structure producing spores in Basidiomycota
Mycorrhiza	Mutualism between fungi and plant roots
Lichen	Mutualism between fungi and photosynthetic partner
Foliose	Leaf-like lichen body form
Choanocyte	Feeding cell in sponges
Ostia	Small pores in sponges
Nematocyst	Stinging cell in cnidarians
Triploblastic	Having three germ layers
Acoelomate	Lacking a body cavity
Scolex	Attachment organ in tapeworms
Gravid proglottid	Tapeworm segment with mature eggs
Corona	Ciliated feeding structure in rotifers
Septa	Internal partitions in annelids
Mantle	Shell-secreting tissue in mollusks
Visceral mass	Internal organ region in mollusks
Torsion	Body twisting in gastropods
Pen	Reduced internal shell in squid
Ecdysis	Molting of exoskeleton
Chelicerae	Feeding appendages in chelicerates
Spiracle	Respiratory opening in insects
Gastric mill	Grinding organ in crustaceans
Pseudocoelomate	Having a body cavity not fully lined by mesoderm
Deuterostome	Blastopore becomes anus
Madreporite	Entry point for water in echinoderm vascular system
Water vascular system	Hydraulic system in echinoderms
Aristotle's lantern	Jaw structure in sea urchins
Notochord	Supportive rod in chordates
Amniotic egg	Egg with protective membranes
Chondrichthyes	Cartilaginous fish
Actinopterygii	Ray-finned fish
Sarcopterygii	Lobe-finned fish
Mammary glands	Milk-producing organs in mammals
Carnassial	Shearing teeth in carnivores
Native	Species naturally occurring in a region
Endemic	Species restricted to a specific area
Invasive	Non-native, ecologically disruptive species
Parasitism	Relationship where one benefits, other is harmed
Keystone species	Species crucial for ecosystem stability
Range	Geographic area where species is found

Additional info: Academic context and definitions were expanded for clarity and completeness. Examples and applications were added where relevant. Table entries were inferred and completed based on standard biology terminology.