The Diversity of Life part II:
Fungi & Animals
Fungi (Ch 16, p. 328)
Note: Fungal classification & phylogenetic relationships described here are based on:
D. S. Hibbett et al. 2007, A higher-level phylogenetic classification of the Fungi.
Mycological Research 111: 509-547.
Importance of Fungi (p. 330)
 Important decomposers (along with heterotrphic bacteria),
recycle materials.
 Some are serious pests & pathogens.
 Yeasts: baking, brewing, & winemaking.
 Important symbiotic associations:
 Mycorrhizae.
 Lichens
Characteristics of Fungi (p. 329)
 Heterotrophic absorbers, grow on/in.
 Feeding strategies:
 Saprophytes.
 Parasites & pathogens.
 Symbionts.
 Majority are multicellular.
 100,000 species described
 likely many more exist!
 Growth form usually filamentous:
 Fungal filaments= Hyphae
 Mass of hyphae=Mycelium
 Cell walls composed of Chitin.
Fungal Reproduction (p. 329)
Propogate by releasing numerous haploid spores:
Asexual
 Asexual spores = conidia.
 Also fragmentation of hyphae.
Sexual
 Zygote usually only truly diploid stage.
 Immediately undergoes meiosis, forms spores.
 Unique sexual cycle: Meiosis, Gamete formation, & 2phase fertilization: plasmogamy, then Karyogamy.
Generalized Fungal lifecycle
Zygote (2N)
Karyogamy
Growth of
reproductive
structures
Meiosis
Dikaryotic
hyphae (1n+1n)
spores
Plasmogamy
Gamete
formation
Hyphae of opposite
mating strains contact
Mitosis
Fungal hyphae (1n)
Main Groups of Fungi
Evolved from common ancestor with animals.
Chytrids
Other fungal Glomeromycetes Ascomycetes Basidiomycetes
(Arbuscular
groups
(Sac fungi)
(Club fungi)
mycorhhizae)
Chytrids
Mostly aquatic & wetsoil fungi.
Spores have flegella.
Glomeromycetes (AMF)
 Also know as arbuscular mycorhhizal fungi (AMF)
 One of the main groups of mycorrizal fungi (p. 322).
 AMF form symbiotic relationships with > 80% of all plant
species.
 Fungus enhances root absorption.
 Plant feeds fungus
 Categorized as endomycorrizae: penetrate into plant
tissues.
AMF make for a healthy, happy plant!
AMF in root tissue
Ascomycetes
Largest group of fungi.
Named for their reproductive sacs or asci.
Asci organized into large visible structures (mushrooms) in
some species.
Life cycle includes extensive dikaryotic phase
Morel
Ascus: The Micrscopic Reproductive
“Sac” of Ascomycetes
Ascus
Basidiomycetes
Named after diagnostic microscopic club-shaped reproductive
organ: Basidium.
Include many familiar mushrooms, toadstools, puffballs, etc.
Several plant diseases (rusts & smuts).
Many are forest ectomycorrhizae.
Extensive dikaryotic phase
Basidium
Mushrooms:
Basidium-producing
reproductive organs
Rust fungus on leaf
Other Fungi
Four 'subphyla' not currently classified into phyla because
phylogenetic relationships still not clear.
 Mainly portions of a polyphyletic group formerly
known as 'zygomycetes'
Phylum Microsporidia
 Earliest-diverging fungal evolutionary branch.
 Small, highly specialized animal parasites.
Microsporidia
Zygomycete' mold on dead leaves
Yeasts
 General term for Unicelluar fungi:
 Most are ascomycetes.
 Saccharomyces sp.
 Commercial yeast of brewing,
winemaking, & baking (p. 331).
Yeast cells
A beer, brewed
using yeast
Lichens (p. 332)
Symbiotic partnerships between fungus & a green alga or
cyanobacterium.
“Trade off”: carbohydrates (fungus) for a safe environment
(Alga).
The fungus-partner is usually an Ascomycete
Many can survive in in harsh environments: Arctic, rocks, etc.
Mycorrhizae: Symbiotic Association
Between Plant Roots & Fungi (p. 332)
Found in 90% plant species!
 Enhance plant nutrient & water absorption
 Fungus fed by plant.
2 main types:
Arbuscular mycorrhizae :
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Phylum Glomeromycota
Penetrate into roots (endomycorrhizae)
Most widespread type, >80% of plants.
Ectomycorrhizae:
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Surround roots but don’t penetrate.
Locally: pines, oaks & other forest trees.
Most are Basidiomycetes, many familiar forest
mushrooms.
Pine seedling with
ectomycorrhizae
Animals (Ch. 17)
 First Animals: PreCambrian period (1200-670
M.Y.A.)
 More than 2 million species.
 Roughly 35 phyla
 0nly part of 1 phylum & 50,000 are vertebrates.
Characteristics of Animals (p. 338-340):
Multicelled.
Heterotrophs.
Feed by ingestion (eating).
Aerobic respiration.
Sexual reproduction.
Motile (move around) for at least part of life.
Complex sequence of embryonic
development.
 3 tissue systems form in most groups:
Ectoderm, Endoderm & Mesoderm (p. 340).
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Diversity in Animal Body Plans (p.340)
Symmetry:
 Radial
 Bilateral
Gut types:
 Saclike (one opening)
 Tubular (2 openings)
Body Cavities
 Presence of a body cavity
(=Coelom) lined with
mesoderm-derived
peritoneum: (most bilateral
lineages).
No coelom: Flatworms & a few
other invertebrates.
Animal Phylogeny (P. 340):
Evolutionary
relationships
among the 9
main animal
phyla.
See Fig. 17.5,
p. 340.
Sponges (Phylum Porifera) p. 341
 Asymetrical
 Minimal differentiation of cells and tissues:
 Flattened surface cells line cavities & outer surface.
 Amoeboid cells between the 2 linings.
 No organs.
 Protein fibers & glass-like structures of silica & calcium
carbonate stiffen the body.
Sponges (Phylum Porifera) p. 340
Feeding:
 Cilia cause water to flow through
pores & chambers.
 Surface cells capture water-borne
bacteria & food particles.
Reproduction:
 Sperm released into water
 Fertilized eggs develop into
microscopic,
 free swimming larvae**.
 Larvae disperse, settle, and begin to
grow.
**Larva (Pl. Larvae):
Immature form of a species.
sponge larvae
Cnidarians (Phylum Cnidaria):
Jellyfish & Anemones, etc (p. 342).
 Radial-symmetric with tentacles.
 Tentacles of some species with poisonous sting.
 Simple tissues each with different cell types.
 Saclike (anus=mouth) gut.
 Two body forms:
 Medusa–free floating, bell-shaped
with tentacles.
Medusae
 Polyp–attached, tube-like, ring of tentacles at
unattached (mouth) end.
 Contractile cells enable movement.
 Medusae move by contracting bells & emitting a water
jet.
Exmples of Cnidarian Diversity
 Colonial cnidarians:
 Portuguese man-of-war:
 medusa & series of tentacled polyps.
 Sea anemone (polyp body form)
 Corals
 Colonies of polyps connected by calcium-rich external
skeletons (the reef).
 Symbiotic algae supplement feeding.
Man-of-war
Sea anemone
Corals
Flatworms
(Phylum platyhelminthes) p. 344
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Bilatteral symmetry
Saclike gut, highly branched for increased
nutrient absorption.
Tapeworms:
Mamalian gut parasitesT
 3 Classes of Flatworms:
Turbellarians:
Free-living
aquatic worms
Flukes:
Microsopic parasites
Tapeworm
Diet?
 Yuck!!!
 Can you believe
this???
 Diet add from
the 1800's
Schistomsomiasis: (p. 344)
A tropical disease from a parasitic fluke (flatworm)
 Alternates between
humans and snails
 Infection by exposure to
infested waters
 Weakness & lethargy
 Liver, spleen, bladder &
kidney damage
 Serious problem in
some tropical countrys.
Annelids (Phylum Annelida)
Segmented Worms (p. 345)
 Bilateral body, segmented into many repeating, similar units.
 Well developed internal organs-(partially repeat in each
segment).
 Rudimentary brain (organ to integrate nerve sensory input) at
head.
 Complete (tubular) gut (digestive tract).
 16,000 or more species.
 Include earthworms, leeches, & marine polychaete worms.
Segments
Leach
Earthworm
Polychaete
Molluscs (Phylum Mollusca)
 Bilateral symmetry.
 Small coelom & fleshy, soft body;
complete gut.
 Mantle: skirt-like tissue that drapes
over body.
 Mantle secrets a shell of calcium
carbonate & proteins.
 Gills for gas exchange.
 Well-developed internal organs
 Nearly 100,000 species.
(p. 343)
Mollusc Diversity: Gastropods
Largest Class: Snails & slugs, etc.
Mollusc Diversity: Bivalves
Clams, Oysters, etc. Shell in 2 parts (valves)
Mollusc Diversity: Cephalopods
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Squid & octopus
Reduced/ absent shell
Streamlined & fast
Large brain, complex behavior
Jet propulsion
Roundworms (Phylum Nematoda)
 Bilateral worms. (P. 346).
 Complete (tubular) gut: both mouth and anus.
 Numerous & widespread
 Many soil-dwelling species
 Most free-living: important detritivores/ nutrient
recyclers in ecosystems.
 Some nematodes are serious plant parasites.
 Human/ mammal parasites: Hookworms,
Trichinella, Elephantiasis, dog heartworm.
Nematodes
parasitic nematodes
killing Insect: for sale
on gardening website!
Phylum Arthropoda: Arthropods
(p. 347-352)
 Largest, most widespread animal group
 > 1,000,000 species “most successful
organisms on earth”
 5 groups: Trilobites, Arachnids, insects,
centipedes/ millipedes, & Crustaceans.
Fossil Trilobite
Arthropod Adaptations
 Hardened exoskeletons:
 Chitin.
 Support body & provide resistance for
muscle contractions.
 Molting (shedding of old, too-small
exoskeleton during growth).
 Jointed appendages (can move at joints
despite rigid exoskeleton.
 Fused and modified body segments.
 Respiratory structures (branching tubes
deliver oxygen directly to cells).
 Division of labor: Juvenile (larval) stages
growth & development, adults: dispersal &
reproduction.
Arachnids: Spiders & their kin (p. 348)
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Spiders
Ticks & mites
Horseshoe crabs
Scorpions
Crustaceans (p. 349)
pillbugs
Crawfish (yummy!!)
Crabs & shrimp
Lobster(also yummy)
Centipedes & Millipedes (p 350)
Insects (p. 350-352)
More than 800,000 species! Largest arthropod (and animal) group!
Butterfly
Fly
Cockroach
Cricket
Moth
Beetle
Echinoderms (Phylum
Echinodermata) (p. 353)
 Radial symmetry with some bilateral features
(bilateral ancestry).
 Endoskeletоn (internal skeleton).
 Decentralized nervous system (no brain).
 Often have defensive spines.
 Related to chordates (that's us!).
Starfish
Sea Urchin
Brittle star
Chordates (Phylum Chordata) p. 355
 Bilateral symmetry
 4 Basic features develop in all
chordate embryos: (p. 383)
Supporting rod for body (notochord).
Dorsal nerve cord.
Pharyngeal slits: grooves in pharynx
(throat)
 Post-anal tail.
 Some of these features may be
modified /disappear as adults develop.
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 All but Tunicates, Lancelets &
hagfishes are Vertebrates (see
p. 355).
Lancelet
Vertebrates (p. 355-360)
 Most of the Chordates
 Dorsal nerve cord enclosed in
a “backbone” of either cartilage
or bone.
 Brain enclosed in protective
cartilaginous or boney
chamber (= Cranium).
 Vertebrate classes:
 Jawless fishes (lampreys)
 Cartilaginous fishes
 Boney fishes,
 Amphibians
 Reptiles (includng birds &
dinosaurs)
 Mammals.
Vertebrate Diversity: fishes (P. 356)
Jawless fishes: Lampreys
Cartilaginous fishes: sharks & Rays
Vertebrate Diversity: Boney Fishes
P. 355
Vertebrate Diversity: Amphibians
P. 357.
Vertebrate Diversity: Reptiles (p. 258)
“Traditional” Reptiles: Paraphyletic group:
Only part of a lineage that also includes
birds & dinosaurs.
Some modern classifications (our book) have
expanded reptiles to include birds.
Vertebrate Diversity: Birds -the Surviving Dinosaurs (p. 359)
Vertebrate Diversity: Mammals
P. 360
Mammary (milk) glands & hair
The End!
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