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BIO 1010
mid term 2
151
Biology
Undergraduate 1
03/11/2009

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Term
Fungi
Definition

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 –

Term
Absorptive heterotrophy
Definition

 

-          Fungi secrete enzymes that digest their food outside their bodies

-          Then they absorb the small nutrient molecules directly

Term
Body forms of fungi
Definition

 

Hyphae – threadlike filaments

Mycellium – branch and form a network

Single cells -  yeast

Term
Cells of fungi
Definition

 

-          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

Term
septate hypha
Definition

Fungi with cross walls 

Term
coenocytic  hypha
Definition

Fungi with no cell walls

Term
Fungal Growth
Definition

 

0 fungi grow longer without getting thicker

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

Term
Fungal Reproduction (fig 17.15)
Definition

 

-          Asexual and sexual

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

Term
Mould
Definition

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

Term
Yeast
Definition

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

Term
Sexual reproduction of fungi
Definition

 

-          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

Term
Sexual Structures of Fungi
Definition

 

-          Used to classify the fungi

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

Term
Five major groups o fungi
Definition

 

-          Chytrids (ancestor group)

-          Zygomycetes

-          Glomeromycetes

-          Ascomycetes

-          Basidiomycetes

Term
Chytrids
Definition

 

-          Only fungi with flagellated spores

-          Probably the earliest linage

-          Common in ponds, lakes, soil

-          Linked to mortality in frogs in central America and Australia

Term
Zygomycetes (fig 17.17)
Definition

 

-          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

Term
Glomeromycetes
Definition

 

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

Term
Ascomycetes
Definition

 

-          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

Term
Basidiomycetes (mushrooms, puffballs and shelf fungi)
Definition

 

-          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

Term
Mushroom life cycle
Definition

 

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

Term

The basic structure that makes up a fungus is the  ___________

a)      Hypha

b)      Anther

c)       Archegonium

d)      Frond

Definition
a) hypha
Term
Defining characteristics of animals
Definition

 

-          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

Term
Animal life cycle
Definition

 

-          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

Term
Hox genes
Definition


-          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

Term
Ecological causes for the Cambian explosion
Definition

 

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

-          Diverse adaptations for feeding, motility and protection

Term
Geological causes
Definition

 

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

Term
Genetic causes
Definition

 

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

Term
Animal body plans vary in:
Definition

 

-          Symmetry

-          Presence and type of body cavity

-          Number of germ layer

Term
A radically symmetrical animal has
Definition

 

-          Top and bottom

-          - but no sides

Term
Animals with bilateral symmetry have
Definition

 

-          Mirror – image , right and left sides

-          Distinct head (anterior) and tail (posterior)

-          A back (dorsal) and belly (ventral)

Term
Organization of tissues of animals
Definition

 

<!--[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

Term
Why have a body cavity
Definition

 

<!--[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

Term
Pseudocoelom
Definition

 only two layers of tissue surrounded by endoderm and mesoderm

 

Term
Coelom
Definition
third layer of tissue that is surrounded by mesoderm tissue on all sides
Term
Sponges are simple, sedentary animals
Definition

 

-          Ingest food, no cell walls, genes

-          A sexual and sexual reproduction

Term
Body form of sponges
Definition

 

-          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

Term
how do sponges feed?
Definition

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

Term
Cnidarians: sea jellies, anemones and associates
Definition


Have true tissues: eumetazoans

-          Radially symmetrical

-          Two tissues

-          Simple nervous and muscle system

-          Marine and freshwater habitats, mostly marine

Term
functions of cnidocytes
Definition

 

 

-          Prey capture (carnivores)

-          Defence

-          a fine threads coiled within a capsule

-          can wrap around prey

Cinidocytes sometimes contain poisons

Term
Polyps:
Definition

 attached on the aboral surface

Term
Medusa:
Definition

 float in the water column, oral surface down

Term
Hydras
Definition

 

-          freshwater

-          small: 25 mm

-          Polyps dominant form

Term
Anemones
Definition

 

-          Purely marine

-          Polyp is the dominant life stage

-          Sessile generally but can move away from danger

Term
sea jellies
Definition

 

-          medusa is the dominant body forms

Term
Corals
Definition


-          Polyps forms secrete a hard external skeleton

Term
Coral bleaching
Definition