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