Biology 1102

Lecture 3

Slide 2 - Fungi

Slide 3 – General characteristics of fungi

Fungi have the following characteristics:

• They are eukaryotic organisms

• Most are multicellular eukaryotic organisms

• Some are unicellular organisms – yeast is the prime example

• They are heterotrophs that consume organic matter

• They do not consume their food source but they absorb nutrients

– Fungus spew out digestive enzymes and dissolve the organic matter externally and then they absorb the food source

• Most fungi are saprotrophic that decomposes organic matters such as leaves or dead bodies

• Some fungi are parasitic

• Some fungi form mutualistic relationship with roots of seed plants where they acquire inorganic nutrients for plants and in return they are fed organic matters by the plant itself

Slide 4 – Mycelium and hyphae of the fungi

Mycelium

Hyphae

Slide 5 – Function of hyphae

– The branching hyphae provide large surface area for the fungi

– The large surface area allows the fungi to increase its absorption rate/amount

– The tips of the hyphae grows while the bundle of hyphae (known as mycelium) absorbs and pass nutrients to the growing tips

– Reproduction occurs when a specific part of the mycelium becomes a reproductive structure while the remaining mycelium provides nutrients it needs

– Fungi cells contains no chloroplasts

– Fungi cells contains a cell wall that is constructed out of chitin (similar to the exoskeleton of a shrimp or crab) and not cellulose

– The storage sugar of the fungi is glycogen and not starch - similar to animals

– Fungi are immobile throughout their life cycles (no flagellated sperm etc.)

Slide 6 – Septae and nonseptate fungi

Septa

Septae fungi Nonseptae fungi

Slide 7 – Fungi – sexual reproduction

Slide 8 – dikaryotic – sexual reproduction of fungi (n + n)

Slide 9 – zygospore fungi

Characteristics of a zygospore fungi (bread mold):

- A horizontal hyphae called a stolon exist on the surface of the bread and eventually

grows into the bread itself.

- Mycelium forms through aggregation of hyphae while rhizoids grows out and anchors the mycelium

- Mycelium carries out external digestion and food absorption

- During asexual reproduction a sporangiophore grows out of the mycelium and at the tip of this structure

a sporangium is formed.

- Sporangium produces haploid spores and are subsequently released into the

environment

Slide 10 – sac fungi - truffles

Sac Fungi – (~30,000 species) they are saprotrophs that digests materials that are otherwise not easily digested (e.g. cellulose, lignin or collagen etc.)

- Truffles belong to this group of fungi

- Yeast is another example but it is

an unicellular sac fungi

Slide 11 – club fungi – common mushrooms

Ergot on wheat

Slide 12 – imperfect fungi - Penicillin notatum

Slide 13 – Magic mushrooms

Slide 14 – deadly mushrooms – Destroying Angel

The structure of alpha-amanitin

Slide 15 – Origin of fossil fuel

Slide 16 – Plant cuticle

Slide 17 – Stomata (stomates)

Slide 18 – Carotinoids (e.g. ß - Carotene)

Slide 19 – Plant sex organs (gametangia)

Slide 20 – Sporophyte and gametophyte generations of plants

Slide 21 – vascular vs. nonvascular plants

Slide 22 – Characteristics of nonvascular plants

Non-vascular plants has the following

characteristics:• Gametophyte is the

dominant generation in non-vascular plants

• The flagellated sperm swim to the egg (located in the archegonia) in a water fill medium

• Due to the flagellated sperm, the non-vascular plants usually require a moist environment.

Slide 23 - Bryophytes

Bryophytes (non-vascular plants) are mosses,liverworts and hornworts

• They do not have internal vascular structures such as xylem or phloem to transport water and nutrients (dissolved sugars and ions) respectively

• They do have leafy and stem like structures that makes up their body

• Bryophytes are capable of being dried out (proceed in a form of dormancy) and still revive itself after the absorption of water

• They have rhizoids that are very similar to roots but again do not have internal vascular structures nevertheless performs anchoring and absorption duties

Slide 24 – Non-vascular plants - hornworts

Hornworts – are usually found in tropical forests, along streams, and in disturbed fields around the world Most species are small and unassuming greasy blue-green patches

Hornworts will generally have a single large chloroplast per cell.

Slide 25 – non-vascular plants - liverworts

Liverworts – all liverworts has the following traits:

A flattened thallus or a leafy body or a lobed thallus or body

Each thallus has a smooth upper surface and a lower surface that possesses numerous rhizoids – hair or root like projections into the soil.

Liverworts are capable of sexual and asexual reproduction

Sexual reproduction depends on the disk-headed stalks that bear antheridia – where the flagellated sperm are produced.

Eggs are produced on the umbrella-headed stalks that bears the archegonia.

After fertilization a tiny sporophyte composed of a foot, short stalk and capsule appears. Windblown spores are produced within the capsule

Slide 26 – non-vascular plants - mosses

Mosses – Mosses can be found from the Artic through the Antarctic although they prefer damp temperate environments. Mosses have the following traits:

Mosses have usually a leafy shoot

Mosses can contain a tremendous amount of water and can become dormant when the environment becomes too dry

Mosses can reproduce asexually by fragmentation – just about any part of the plant can produce leafy shoots

This form of reproduction is most common in desert, artic and Antarctic regions

Mosses have Rhizoids those functions as an anchor. Rhizoids also contain the antheridia and archegonia

The antheridia consist of a short stalk, an outer layer of non-reproductive cells used for protection and an inner mass of cells that becomes the flagellated sperm

Slide 27 – Vascular plants

Slide 28 – vascular plants

Slide 29 – Anatomy of roots

Slide 30 – Anatomy of a plant stem

Slide 31 – Anatomy of a vascular leaf

Slide 32 – Microgametophyte (e.g. pollen)

Slide 33 - Megagametophyte

Slide 34 - horsetail

Slide 35 – Whisk fern

Slide 36 – Ferns – fiddle head and fronds

Slide 37 – Lifecycle of ferns

Slide 38 – Gymnosperm lifecycle

Slide 39 – conifers - Redwood (Sequoia sempervirens)

Slide 40 - cycads

Slide 41 – Ginkgo trees

Slide 42 - Gnetophytes

Slide 43 - Dicot stems

Slide 44 – monocot stems

Slide 45 – Lifecycle of an Angiosperm

Slide 46 – anatomy of a flower