BIOL 112

Lab exam 2

Key Fungal Characteristics

Cell walls contain chitin (rather than cellulose).

Produce melanin (pigment cells found in hair and skin)

The main body of most consists of filaments called hyphae

Lack true tissue

Septate hyphae

 hyphae divided into individual cells by cross walls (septa).

Aseptate hyphae

lack cross walls; nuclei share a common cytoplasm.

Mycelium

A mass of underground hyphae

Mutualistic

both partners benefit (e.g., lichen with algae/cyanobacteria)

Saprophytic

feed on nonliving organic matter (e.g., molds growing on dead material)

Commensalism

one partner benefits, the other is neither harmed nor helped

Parasitic

one partner benefits at the other’s expense (e.g., cordyceps aka zombie fungus)

Fungi reproduction

Delayed karyogamy: This is when the gametes fuse without the nuclei fusing immediately

Ascomycota and Basidiomycota

Septate hyphae

Form Ectotrophic Mycorrhizae: a type of symbiotic relationship where fungal hyphae form a sheath & network around plant roots w/out penetrating the root cells

Form fruiting bodies - the large visible structures

Major Phyla of Fungi

Chytridiomycota

Zygomycota

Ascomycota

Basidiomycota

Glomermycota 

Zygomycota

(bread molds, Rhizopus)

Aseptate hyphae

Saprophytic

Form zygosporangium - product of two haploid gametangia

Multinucleate and produces haploid spores in favorable conditions

Ascomycota

(sac fungi, e.g., Penicillium, most yeasts)

Septate hyphae

Fruiting body = ascocarp

Form 8 haploid ascospores per ascus

parasitic sac fungi

Extend specialized absorption cells (haustoria)

from hyphae into plant cells to steal water & nutrients

Imperfect sac fungi

Not technically ascomycetes. Do not have ascocarp stage. Lack sexual reproductive structures. Reproduce asexually via conidiophores and conidia

Basidiomycota

(club fungi, e.g., typical mushrooms)

Septate hyphae, lack asexual reproduction

Fruiting body = basidiocarp with basidia that produce basidiospores

(sexual reproduction)

Glomeromycota

arbuscular mycorrhizal fungi

Yeasts

are basically highly derived, unicellular Ascomycetes or Basidiomycetes

that have lost the ability to form hyphae & other multicellular structures

Lichens

Symbiotic association of fungi (usually Ascomycota or Basidiomycota yeast) with algae or cyanobacteria. The organisms within this association all reproduce independently

Can survive harsh environments; good environmental indicators.

Kingdom animalia

Multicellular, heterotrophic, no cell walls, typically diploid.

Can be classified by symmetry (asymmetric, radial, bilateral), number of germ layers, and body cavities.

Asymmetrical body symmetry 

lack of symmetry. Found in primitive animals (Porifera-sponges)

Radial body symmetry

Parts radiate from the center. No left or right.

(Cnidarians/Ctenophores/Adult Echinoderms - starfish, sea urchins, etc)

Bilateral body symmetry

Has a left and right. Roughly equal parts if cut down the center (all other animals - insects, mammals, birds, etc)

Germ layers: no true tissue 

one germ layer (sponges and placozoa)

Germ layers: diploblastic

two layers- endoderm and ectoderm (Cnidarians/Ctenophores)

Germ layers: triploblastic

three layers- ectoderm, mesoderm, endoderm (everything else)

Endoderm

innermost layer, becomes gut/liver/lungs

Mesoderm 

middle layer, becomes the skeleton/heart/kidney/muscle

Ectoderm

outermost layer, becomes the skin and nervous system

Acoelomate

no body cavity

Psuedocoelomate

Body cavity between mesoderm & endoderm

Coelomate

 Body cavity completely lined with mesoderm

Purposes of coelom

Cushions/protects the suspended organs

Allows internal organs to grow/move independently of outer body wall

Porifera

(ex. Glass sponge)

Simplest invertebrates

Asymmetric or “no symmetry.”

No true tissues (only a loose assemblage of cells).

Skeletons can be fibrous (spongin) or mineralized (silica or calcium carbonate spicules).

Spongocoel: cavity within the sponge

Choanocytes

(collar cells)

create water current and capture food. Line the walls of the internal cavity

Amoebocytes

mobile cells in the sponge that transport nutrients and form spicules

Spicules

spikey structure that forms the sponge’s skeleton

Osculum

water exits through this opening

Porifera body types 

Asconoid (simplest), lots of dead space

Syconoid

Leuconoid (most common, highest complexity)

Cnidaria

(Coral, Jellies, Anemones)

Radial (or biradial) symmetry, diploblastic (endo- and ectoderm).

Cnidocytes with nematocysts (stinging cells/organelles).

Two major body forms: polyp (asexual) and medusa (sexual)

Four main classes of Cnidaria

Hydrozoa

Scyphozoa

Cubozoa

Anthozoa

Hydrozoa 

both polyp and medusa forms (e.g., Obelia, Hydra).

Scyphozoa 

true jellies (medusa dominant)

Cubozoa 

box jellies (medusa only, highly venomous).

Polyp phase is dominant

Anthozoa  

sea anemones and corals (polyp only).

Polyp body form

Some make exoskeletons of CaCO2

2 major clades of protostomes

Ecdysozoa (animals that molt an exoskeleton, e.g., Arthropoda, Nematoda).

Lophotrochozoa (animals with trochophore larvae or lophophores, e.g., Annelida, Mollusca, Brachiopoda, Platyhelminthes).

Arthropoda

Largest animal phylum, with jointed appendages, segmented body, and a chitinous exoskeleton.

Open circulatory system; coelomate

Myriapoda

Subphyla Arthropoda

centipedes (one pair of legs per segment, venom fangs) and millipedes (two pairs per segment, herbivores)

Chelicerata

Subphyla Arthropoda

spiders, scorpions, ticks, horseshoe crab.

Chelicerae (fangs/pincers), two body regions (cephalothorax + abdomen), 4 pairs of legs + 1 set of chelicerae + 1 set of pedipalps (6 pairs of appendages total), book lungs or gills to breathe

Hexapoda

Subphyla Arthropoda

(Insects): head, thorax, abdomen; 3 pairs of legs, often wings.

Spiracles and trachea to breathe

Crustacea

Subphyla Arthropoda

crayfish, lobsters, crabs. Two pairs of antennae, biramous appendages, mostly marine. Each body segment has 2 appendages. Gills or branchiostegal lungs to breathe

Why are hexapoda and crustacea more closely related to each other than any other two groups in Arthropoda?

Synapomorphies between them:

Heavily segmented bodies

Compound eyes

Well-developed mandibles

3 clearly-distinguishable body regions

Nematoda (Roundworms)

Pseudocoelomate

Complete digestive tract, longitudinal muscles only (whip-like movement).

Many are free-living (e.g., vinegar eels), some parasitic (e.g., Trichinella, Ascaris)

Platyhelminthes (Flatworms)

Acoelomate, dorsoventrally flattened (flat bodies). Typically hermaphroditic.

First example of cephalization in the fossil record

Some are free-living (e.g., Planaria or turbellaria), many are parasitic (flukes or trematoda, tapeworms or cestoda)

Cestoda (tapeworms)

Have:

Scolex: attachment organ

Proglottids: reproductive segments, break off the end of the worm when fully mature

Annelida (Segmented Worms)

Coelomate, segmented body divided by septa, closed circulatory system.

Two main clades:

Errantia: free-living marine worms (parapodia, bristles called chaetae).

Sedentaria: includes earthworms, leeches, tubeworms.

Clitellum: glues them together when mating

Mollusca

Coelomate, many have an open circulatory system except cephalopods (closed).

Key features: Foot, Visceral Mass (contains organs), Mantle (secretes shell usually), often a Radula (scraping).

4 major clades of mollusca

Polyplacophora

Gastropoda

Bivalvia

Cephalopoda

Polyplacophora

Mollusca:

chitons, segmented shell made up of 8 plates

Gastropoda

Mollusca:

snails, slugs, nudibranchs

Bivalvia 

Mollusca:

clams, oysters, mussels; two hinged shells

Incurrent & excurrent siphon

4 oversized gills for filter feeding

Cephalopoda

Mollusca:

squid, octopus, cuttlefish, nautilus

Intelligent, closed circulation

Chromatophores: pigment cells to change color

Octopi = 8 arms; sequid = 8 arms + 2 tentacles with hooks

Pen: internal remnant of shell

Brachiopoda

Lophophore for feeding, pedicle for anchoring; superficially resemble clams but are not mollusks.

Two classes: Inarticulata (no teeth on valves, e.g., Lingula) and Articulata (toothed valves, “lamp shells”).

Protostomes 

# of germ layers: triploblastic

coelom formation: schizocoelous

body cavity (coelom) type: coelomate, acoelomate, or pseudocoelomate

cell fate: determinate

blastopore fate: mouth

Deuterostome

# of germ layers: triploblastic

coelom formation: enterocoelous

body cavity (coelom) type: always coelomate

cell fate: indeterminate

blastopore fate: anus

3 major phyla of Deuterostomes

Major phyla: Hemichordata, Echinodermata, Chordata

Schizocoelous

refers to coelom formation by splitting a solid mass of mesoderm

Enterocoelous

describes coelom formation from pouches that bud off the gut

Echinodermata

Spiny skin, slow-moving or sessile.

Secondary pentaradial symmetry (larvae bilateral, adults radial).

Water vascular system with tube feet, used in movement and feeding.

Internal skeleton made of calcite plates called ossicles.

Major classes:

Crinoidea, echinoidea, holothuroidea, asteroide, ophiruoidea

Crinoidea

Major classes of Echinodermata

(sea lilies, feather stars) – earliest branch, filter feeders. Only taxon of Echinoderms that can swim

Echinoidea

Major classes of Echinodermata

(sea urchins, sand dollars) – no arms, move slowly with spines, have “Aristotle’s Lantern” (feeding apparatus)

Holothuroidea

Major classes of Echinodermata

(sea cucumbers) – elongated shape, can eviscerate their intestines

Asteroidea

Major classes of Echinodermata

(sea stars) – 5 arms (often), tube feet with suckers, can eviscerate stomach. Carnivores and often even cannibals.

Ophiuroidea

Major classes of Echinodermata

(brittle stars) – central disc and long/thin/flexible arms, tube feet lack suckers

Chordata

Note: Chordate does not mean vertebrate

All chordates share 5 key traits at some point in development:

notochord, dorsal, hollow nerve cord, pharyngeal gill slits, post-anal tail, endostyle/thyroid glands

Notochord

Chordata

Longitudinal flexible support rod between the gut and nerve cord.

Becomes the disks between vertebrae in adults

Dorsal, hollow nerve cord

Chordata

Rolled tube of ectodermal tissue located dorsal to the notochord. Forms brain and spine in higher vertebrates

Pharyngeal gill slits

Chordata

Openings in the pharynx. Develop into gills for aquatic chordates.

Jaw/support hearing for terrestrial vertebrates

Post-anal tail

Chordata

 A tail that extends past the anus. Often seen in embryonic development and lost later in life.

Endostyle/thyroid gland

Chordata

Ciliated cells located at bottom of pharynx.

Endostyle for invertebrate chordates - used to sweep food toward esophagus.

Thyroid gland in higher, vertebrate chordates - regulates heart rate, body temp, metabolism.

HOX genes

Chordata

Genes responsible for initiating development of body structures in the correct places.

Most Chordates have 13 sets. Urochordates only have 9

Subphylum Cephalochordata

Chordata

(sea lancelets)

Retain all chordate traits unmodified throughout their life.

Filter feeders, notochord extends to front of head, buccal cirri (mouth tentacles)

Subphylum Urochordata

Chordata

(tunicates/sea squirts)

Most primitive chordate group

Larvae have all chordate traits; adults lose tail/notochord.

Outer “tunic” of cellulose-like tunicin.

Subphylum Vertebrata

Chordata

Retain all 5 chordate traits but may be heavily modified or only appear during some life stages then disappear.

Have a vertebral column replacing most of the notochord; a skull; advanced organ systems.

Two infraphyla/superclasses:

1. Agnathans

2. Gnathostomes. Two traits for all Gnathostomes:

Jaws

Two sets of paired appendages

Class Myxini

Infraphylum Agnathans/Cyclostomes

Hagfish

Problematic classification. No backbone, so technically not a vertebrate but DNA evidence places them with vertebrates

Infraphylum Agnathans/Cyclostomes - Class Petromyzontida

Lampreys

Jawless, skull & rudimentary backbone, rasping tongue to suck blood, &

adults are parasitic.

Class Chondrichthyes

Infraphylum Gnathostomata

Sharks & Rays

Full skeleton made of cartilage, placoid scales (homologous to teeth)

Class Actinopterygii: Ray-finned Fishes

Gnathostomata

Ray-finned Fishes

Bony rays in fins (homologous to phalanges), swim bladder for neutral buoyancy, cycloid scales

ex. Perch, bass, zebrafish, carp, etc

Sarcopterygii: Class Actinistia

Gnathostomata

Lobe-finned Fishes

Also known as Coelacanthiformes

Bones in fins homologous to those of tetrapod limbs

Most members extinct

Sarcopterygii: Class Dipnoi

Gnathostomata

Lungfish

Import evidence for sequence of evolution because they use gills & lungs AND can walk on their fins out of water for short periods of time

Lungs are a modified swim bladder

Live in stagnant ponds/swamps & during dry periods can burrow into mud to hibernate

Vertebrata:Class Amphibia

Chordata

Incompletely terrestrial, skin (integument) contains some keratin to protect against some desiccation, gas exchange through their moist skin

ex. Frogs, newts, salamanders, etc

Vertebrata: Class Reptilia

Chordata

Amniotoa

Best adapted for a dry environment

Tough skin with epidermal scales does not need water and completely prevents water loss

Leathery or hard shells on amniotic eggs prevent water loss

Includes Turtles, Snakes, Lizards, Crocodiles, & Birds/Chicken

Feathers - modified scales

Flight adaptations: Keeled sternum, large pectoral muscles, wings

Vertebrata:Class Mammalia

Chordata

Amniota

All mammals are endothermic to some degree – they regulate their own internal body temperature.

Most have live-born offspring

All have hair or fur on their bodies (at least during embryogenesis), 4 chambered hearts (with a left aortic arch), and produce milk for their offspring, hence mammary glands

ex. Cats, dogs, mice, elephants, primates….

Anapsid skull

no holes (temporal fenestrae) behind eyes (Amphibians & Turtles)

Synapsid skull

one hole behind eyes (Mammals)

diapsid skull

two holes behind eyes (Dinosaurs & Birds, other Reptiles except Turtles)

Clade Amniota (Reptilia & Mammalia)

tetrapods adapted to dry environments

Thicker skin with increased keratin

Well-developed lungs

Internal fertilization

Amniotic egg

Parts of amniotic egg

Amnion: fluid-filled membrane that protects the embryo

Allantois: membrane used in gas exchange and waste removal

Yolk Sac: nourishes the embryo

Chorion: encloses the embryo & all internal membranes

Shell: prevents desiccation & allows gas exchange

Open Circulatory System

blood not always contained in vessels, blood flows freely around organs

(arthropods, most mollusks).

Closed circulatory system

 blood always in vessels, more efficient (vertebrates, annelids, cephalopods)