Diversity

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Transcript Diversity

Diversity

2.7 billion years ago, microbes invented
photosynthesis
 Water
split to get H needed to turn CO2 into
sugars, O2 left behind
 All the iron on the surface rusted
 Oxygen accumulated

Organisms adapted to new world
 They
could get bigger; more efficient
metabolism
Eukaryotes
Bigger, more complicated cells than
prokaryotes
 Multicellular organisms developed
 Four kingdoms of eukaryotes currently
recognized.

Fungi, the champion decomposers
Familiar terms: what do they mean exactly?
 Molds: types of fungi that grow as long
threads or filaments.

 When

Yeasts: another way fungi can look; oval,
unicellular in appearance.
 Some

they reproduce, they look different.
fungi can grow as yeasts or molds.
Mushrooms: these are reproductive
structures of certain types of fungi.
How do Fungi grow?

Fungi are heterotrophs
 They
are the great decomposers, break down
all kinds of polymers. Can destroy wood,
rubber, paint, all types of things.
 They are never photosynthetic!

Fungi grow into, through their food.
 They
release enzymes that break things down
 They take up resulting small molecules
 They grow at the tips and penetrate.
Fungi and plants

Some fungi are parasites
 Many
plant diseases are caused by fungi
 Fusarium, for example

Many fungi grow along with plants
 Myco
(fungi) rrhizae (roots) = mycorrhizae
 Fungi growing with plant roots help furnish the
plant with minerals from the soil
 Plants leak nutrients to feed fungi
 Both prosper
Fungi and humans

As decomposers, important in ecosystem
 Industrial

problems
Some cause disease
 Athlete’s
foot, yeast infections, histoplasmosis
 Serious infections with diseases like AIDS

Source of important antibiotics
 Penicillium

is a fungus
Important in food and other industries
 Citric
acid, soy sauce, cheeses, mushrooms
How are they classified?
Once again, it’s about sex.
 Three main types of fungi

 When
two different mating types get together,
they make sexual spores
 The type of structure the spores are found in
determines the type of fungus


Mushroom is a type of spore-bearing structure
Fungi also reproduce asexually too
 They
make lots of spores this way, but not
involved in classification
Sexual reproductive structures that
Fungi make
Protista: one kingdom, or 8?
The Protists are unicellular eukaryotes
 For “pond scum” they show incredible
diversity

 Protists
were always lumped together by what
they aren’t.
 New schemes suggest grouping them into 8
or more different KINGDOMS
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As different from each other as they are from
plants and animals.
Is there an easy way to learn about
the Protists?

Here’s one. Divide them into 3 groups:
Plant-like
Animal-like
Fungus-like
Plant-like Protists
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
Contain chloroplasts
Representatives
 Diatoms (right).

Diatomaceous earth = fossilized
diatoms: abrasives and slug
repellants.
 Red,

brown, yellow algae
Seaweed, source of agar
 Dinoflagellates
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Neurotoxins and red tide
http://www.bhikku.net/archives/03/img/diatoms.JPG
www.enviroliteracy.org/ article.php/534.html
Animal-like protists
Capable of ingesting their food.
 Capable of moving around
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 Amoebas
 Protozoa

with flagella or cilia
Disease-causing protists belong
to this group
 Diarrhea,
malaria, STD
http://en.wikipedia.org/wiki/Slime_mold
http://ar.geocities.com/seti_argentina/estamos_solos/ameba.jpg
Fungus-like

Water molds
 Motile
by flagella (fungi aren’t.)
 Phytophora infestans, cause of
Irish potato blight

Slime molds
 “the
blob”, one giant cell or groups
of cells that crawl over the ground
 Digest everything in their path
res2.agr.ca/lethbridge/ emia/SEMproj/phyinf_f.htm
http://en.wikipedia.org/wiki/Slime_mold
The Kingdom Plantae
Plants are highly successful
 Photosynthetic, use sunlight energy and
carbon dioxide

 Also
need minerals to grow
The world of Plants
The most abundant and successful type of
plant are flowering plants, the Angiosperms.
 There’s actually 9 other completely different
types of plants.

 Mosses
 Ferns
 Cycads
 Conifers
6
others
(most evergreens w/ needles)
Examples: most primitive to most
advanced

Mosses
 Have
no roots
 No seeds

Ferns
 Produce
spores, not
seeds

Gymnosperms
 Naked

seeds, in cones
Angiosperms
 Flowers
and seeds
Pictures cited

http://www.mpm.edu/collect/fern-6.gif
www.maxwaugh.com/ arb02/moss.html
http://www.huntergardens.org.au/images/conifer1.jpg
www.sbs.utexas.edu
What have angiosperms got that
makes them good?
Specialized structures for pulling water out
of dry ground: roots
 Specialized structures for exchanging
gases with the atmosphere and collecting
sunlight: leaves
 Structures for holding the leaves up where
they can do these things: shoots


Flowers
 Attract
pollinators that spread male gametes
(pollen, from anthers) to female gametes
(inside ovaries)
 Provide a protective place for embryo (within
seeds) to form.

Seeds are within or attached to fruit.
 Fruit
is a mechanism for dispersal of seed
 Some is eaten and excreted elsewhere
 Some sticks and is carried about
 Some blow, some float, many strategies