Fungi

-          Domain of eukarya

-          Kingdom of fungi

-          Found in the fossil record (460 million years ago)

-          Thought to have evolved from a unicellular flagellated ancestor

-          Originated 1.5 billion years ago

-          Heterotrophic – but they do not ingest food

-          The absorb nutrients from other organisms –

-          Fungi secrete enzymes that digest their food outside their bodies

-          Then they absorb the small nutrient molecules directly

Hyphae – threadlike filaments

Mycellium – branch and form a network

Single cells -  yeast

-          Wall are made of chitin (strong, but flexible)

-          The chains of cells in some hyphae are separated by crosswalls

-          The walls have pores that allow some things to pass

Fungi with cross walls 

Fungi with no cell walls

0 fungi grow longer without getting thicker

Very high growth rates: a mycelium can add a kilometre a day

-          Asexual and sexual

-          Fungi produce huge numbers of asexual spores, each of which can germinate to form a new fungus

 any rapidly growing fungus that reproduces asexually by producing spores, at the tips of specialized hyphae

 any single celled fungus that reproduces asexually by budding – inhabit liquid or moist habitats

-          Haploid mycelia

-          Different mating types

-          Release signalling molecules

-          Grow toward each other

-          Fusion of cytoplasm without fusion of nuclei: heterokaryotic stage

-          Cells contain two genetically distant haploid nuclei

-          Hours or centuries may pass before parental nuclei fuse to form a short-lived diploid phase

-          Zygotes undergoes meiosis inside specialized reproductive structures and disperse haploid spores

-          Used to classify the fungi

-          Fungi that have no known sexual stage are called imperfect fungi

-          Chytrids (ancestor group)

-          Zygomycetes

-          Glomeromycetes

-          Ascomycetes

-          Basidiomycetes

-          Only fungi with flagellated spores

-          Probably the earliest linage

-          Common in ponds, lakes, soil

-          Linked to mortality in frogs in central America and Australia

-          Ex. Bread mould, moulds that rot produce

-          Characterized by their zygosporangium

-          Can tolerate harsh conditions

-          When conditions are favourable, parental nuclei fuse, diploid nucleus undergoes meiosis to form spores

-          Sexual reproduction in the fall: genetic diversity

-          Haploid spores mature in the spring

-          Can reproduce asexually for many generations

-          Form mychorrizae that invade plant root with distinct structures called arbuscles

-          Unicellular yeasts to morels and cup fungi

-          Named for the sac like asci that hold the sexual spores

-          Varity of habitats: marine, freshwater, terrestrial

-          Pathogenic forms

-          Lichens

-          Named for their basidia (their sexual spores)

-          Spores are called basidiospores

-          Mushrooms are formed from tightly packed hyphae

-          They are reproductive structure is the part that we eat

1)      Fusion of the two hyphae of different mating types

2)      Growth of heterokaryotic mycellium

3)      Diploid nuclei

4)      Spores released

5)      Germination of spores and growth of myclia

The basic structure that makes up a fungus is the  ___________

a)      Hypha

b)      Anther

c)       Archegonium

d)      Frond

-          Cells lack walls

-          Have special junctions that join cells

-          Have muscle cells for movement and nerve cells for conductions impulses

-          Unique embryonic stages

-          Unique genes

-          Haploid egg and sperm produced by meiosis meet in fertilization

-          The newly formed diploid stage is called a zygote

-          The zygote undergoes a series of mitotic divisions without changing total volume

-          Eventually a hollow ball of cells is formed, this is called a blastula

-          Some cells migrate an infolding in the hollow

-          Gastrulating occurs when a tube is formed in the embryo; it is now know as gastrula

-          The opening formed during gastrulation will become the mouth in some animals

-          The endoderm is the inner layer

-          The ectoderm is the outer layer

-          The larva is an immature form that looks different from the adult

-          Metamorphosis is when the larva undergoes a major change of body form to become the adult

-          A group of genes that controls the transformation from zygote to adult in animals

-          Control the events that lead to different body forms in different animals

-          Evolution of hard body coverings: increasingly complex predator-prey relationships

-          Diverse adaptations for feeding, motility and protection

-          Atmospheric oxygen reached a high enough concentration to support the metabolism of more active, mobile animals

-          The Hox complex of regulatory genes variation in these genes produced animal diversity

-          Symmetry

-          Presence and type of body cavity

-          Number of germ layer

-          Top and bottom

-          - but no sides

-          Mirror – image , right and left sides

-          Distinct head (anterior) and tail (posterior)

-          A back (dorsal) and belly (ventral)

<!--[if !supportLists]-->-          <!--[endif]-->Sponges lack true tissues

<!--[if !supportLists]-->-          <!--[endif]-->In other animals, cell layers formed during gastrulation give rise to tissues and organs

<!--[if !supportLists]-->-          <!--[endif]-->Some animals have only ectoderm and endoderm, but most animals also have a mesoderm

<!--[if !supportLists]-->-          <!--[endif]-->Filled with fluid

<!--[if !supportLists]-->-          <!--[endif]-->Cushions internal organs

<!--[if !supportLists]-->-          <!--[endif]-->Allows organs to grow and move independent of the body wall

 only two layers of tissue surrounded by endoderm and mesoderm

-          Ingest food, no cell walls, genes

-          A sexual and sexual reproduction

-          2 layers of cells

-          Separated by gelatinous region

-          Class, carbonate or protein fibres for support

-          Can be simple or more folded and complex

-          Sponges can be put through a sieve, and the cells will eventfully re-aggregate and function as a sponge

-          Outer layer with pores

-          Inner layer

·         Flagellated choanocytes

·         Filters food and engulfs it by phagocytosis

-          Amoebocytes

·         Wander through the middle body region

Water is drawn in through pores in the body wall into a central cavity, and then flows out rhough a larger opening

Have true tissues: eumetazoans

-          Radially symmetrical

-          Two tissues

-          Simple nervous and muscle system

-          Marine and freshwater habitats, mostly marine

-          Prey capture (carnivores)

-          Defence

-          a fine threads coiled within a capsule

-          can wrap around prey

Cinidocytes sometimes contain poisons

 attached on the aboral surface

 float in the water column, oral surface down

-          freshwater

-          small: 25 mm

-          Polyps dominant form

-          Purely marine

-          Polyp is the dominant life stage

-          Sessile generally but can move away from danger

-          medusa is the dominant body forms

-          Polyps forms secrete a hard external skeleton

-          Corals have symbiotic algae to provide sugars from photosynthesis: sometimes a majority of the energy requirements

-          Coral bleaching occurs when the symbiotic algae die

-          Caused by raise in temperature, poor water quality and a number of other factors

budding or fissioning

-       gametes shed in the water column

-          Bilaterally symmetrical

-          Acoelomate

-          Thin and ribbon like

-          Three groups: free living; flukes; tapeworms

 trochophore

-          Highly branched GVC

-          Light-sensitive eyespots and flaps to detect chemical

-          Nerve cells from a simple brains, and a pair of nerve cords

-          Can regenerate

-          Reproduce sexually and asexually by fissioning

-          Parasitic flatworms with complex life cycles

-          Flukes have suckers to attach to their hosts

-          Tapeworms inhabit the digestive tract of vertebrates: can have hook and/or suckers

-          Single unit body

-          Suckers for attachment

-          Complex life cycle with multiple hosts

-          Mammals usually host the adult stages: definitive host

-          Ribbon-like body with repeated units

-          Armed with hooks and suckers on anterior end for attachment (scolex)

-          Posterior units: full of eggs and sperm, digestive tract, absorb nutrients from the intestimes of their host

-          Round worms

-          Free living and parasitic

-          Pseudocoelomate, bilateral symmetry

-          Have a cuticle which must be shed for them to grow

-          Live almost every environment: 500 000 species

-          The shedding of the cuticle groups nematodes in the Ecdysoa with arthropods

-          A hormone called acdysone causes the shedding: ecdysis

-          Have a complete digestive tract, muscles

-          Fluid in their body cavity gives them a hydrostatic skeleton

-          Contract muscles to bend body against non-compressible fluid

-          Nematodes move in a whip like motion

-          Mosquito carrying larvae bites dog

-          Larvae are passed into dogs blood stream

-          Develop into adults

-          Migrate to the heart and lungs

-          Mature males and females mate within the dog and release them into the blood stream where they can be picked up by mosquitoes

-          At least 50 species

-          Range of severity

-          Trichinosis: from eating infected uncooked pork: larvae encyst in host tissues

-          Inhabit small intestine

Shell – protein

Mantle – secretes the shell

Muscular foot – locomotion

Radula – rasping organ used to scrape food

Visceral mass – internal organs

Note that molluscs have a coelom and a complete digestive tract

Gills (most)- respiratory structures, housed in the mantle cavity

Note the complexity of the organ system if the visceral mass of molluscs

Excretory : kidney

Heart and gills – circulation and respiration

Circulatory system – unlike flatworms and nematodes

Nerve cords

Separate sexes in most

Gastropods: snails and slugs

Bivalves – clams, scallops and oysters

Cephalopods – squids and octopi

Chitons

Habitat: freshwater, marine, terrestrial

Land snails are the only molluscs that live on land

Most protected by a single spiral shell

Land snails do not have gills, lining of the mantle cavity acts as a lung

-          Have lost their shell during evolution

-          Land slugs have a pneumostome: opening for air

-          Sea slugs often have frilly projections that serve as gills

-          Marine and freshwater

-          Shell composed of two valves

-          Use their foot for digging or anchoring

-          Mussels tend to attach to substrates; clams and scallops tend to move more

-          Marine

-          Have a shell composed of 8 plates on dorsal surface

-          Most consume algae and seaweed

-          Some are carnivorous

-          Fast agile predators

-          Some have external shells: nautilus

-          Others have a small internal shell: squid, cuttlefish and octopus

Cephalopods are good swimmers and hunters

-          Use their mantle cavity as a hydrostatic skeletonephalopod nervous system

-          Large brains

-          Complex eyes

-          Eye forms clear images

-          Octopus how learning abilities

-          Bilateral summetry

-          Trocophore larvae

-          Segmented bodies

-          Terrestrial – damp soil

-          Marine: water and sediments

-          Freshwater

-          Closed circulatory system: blood remains enclosed in vessels (remember molluscs habe an open circulatory system)

-          Subdivision of the body along the entire length

-          Series of repeated parts

-          Gives flexibility

-          Earthworms and relatives

-          Polychaetes

-          Leeches

-          Hermaphrodites

-          Mate by cross fertilization; cocoons

-          Eat their way through soil: extract nutrients as soil passes along digestive tract

-          Ecologically very important: aerates the soil

-          Improve soil texture with castings (feces)

-          Circulatory and longitudinal muscles: work against the coelomic fluid: hydrostatic skeleton

-          Bristles allow them to have tractionégrip surface – 4 per segment

-          Dorsal and central blood vessels, connected by `hearts`- pumping vessels

-          Repeated excretory organs in each segment

-          Marine annelids

-          Named for their many bristles

-          Bristles aid in movement, can be used as gills, or for feeding

-          Sedentary and active types

-          Free living and carnivore

-          Fresh water

-          Have jaws that are razor life to slit the skin of prey

-          Leech anticoagulants used to dissolve blood cots

-          Hirudin inhibits blood coagulation by binding to a protein need for coagulation

-          Leeches secrete anaesthetics which are being studied for therapeutic used as well

-          Bilateral symmetry

-          In the Ecdysoa with nematodes: shed their outer covering

-          A million species, 10^18 individuals

1.       Segmented

2.       Hard exoskeleton... must molt to grow

3.       Jointed appendages

-          Several distinct groups of segements that fuse during development

-          Head, throax and abdomen

-          Separate functions in each segment

-          Open circulatory system

-          Gas exchange: aquatic species have gills

-          Chelicerates

-          Millipedes and centipedes

-          Crustaceans (including insects)

-          Arachnids, horseshoe crab

-          Named for their chelicerae (mouthparts)

-          Most live on land

-          Their ancestors were the first terrestrial carnivores

-          Living fossils

-          Abundant 300 million years ago

-          Common on Atlantic and gulf coasts of US

-          Body segmentation

-          An exoskeleton

-          Jointed appendages

-          Flight

-          A waterproof cuticle

-          A complex life cycle with short generations and large numbers of offspring

-          Insects mouthparts are adapted for various types of feeding

-          Chewing (grasshoppers)

-          Biting and tearing prey (mantids)

-          Lapping up fluids (houseflies)

-          Piercing and sucking fluids out of plants (aphids) and animals (mosquitoes)

-          Include metamorphosis

-          Different body form as they develop from larva to an adult

-          Division of resources: adults and larvae do not compete

Complete- flies, bees, moths, butterflies

Incomplete – grasshoppers and cockroaches

-          Pupa is non-feeding

-          Rebuilds body

-          Larva specialized for eating and growing

Incomplete

-          Larvae à adult achieved through multiples molts

-          No pupa formed

-          Modifications to antennae, wings, and bodies

-          Imitation of other organisms

-          Camouflage

-          Predator-prey-co-evolution

During embryonic development...

In protosomes:

1^st opening becomes the organism’s mouth

1^st opening becomes the anus, 2^nd opening becomes the mouth

-          Marine

-          Slow-moving or sessile radically symmetrical organisms

-          Endoskeleton of hard calcareous plates under a thin skin

-          5 part symmetry

-          Water vascular system