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