BIOL. 203 - Diversity

Second Exam page

Third Exam Page

 

NOTES FROM LECTURE

 

 

Concept of two kinds of organisms

Plants and Animals.

Old school of thinking

all organisms were thought to be either plant or animal. Two Kingdoms

Concept that most people have of What a plant is.

 

There are many true plants that lack one, some or all of these structures.

Algae -none of the above-

Psilotum -stems only, no leaves or roots

SO HOW WOULD YOU DISTINGUISH A PLANT FROM AN ANIMAL?

Plant vs. Animal

Problems with this system and concept esp. for some forms of organisms

Alga - Euglena

Green, photosynthetic Highly motile, both Autotrophic and Heterotrophic

Fungi Look like plants, have structure that resembles plant stems, but

but no fungi are green, none are Autotrophic all are Heterotrophic

Green animals. Birds and reptiles

Stationary animals (marine barnacles, sea fans, etc.)

New concept! Why does it have to be either a plant or an animal? Why not another life form. (Chickens really are birds)

New concept, not just two kingdomsbut five kingdoms

Classification starts at the cellular level

Five Kingdoms are

We will study the first 4 kingdoms and concentrate on the last one, the Plant Kingdom.

Naming or Organisms. an accepted International System commonly refered to at the Binomial system of Nomenclature.

every organism has a name consisting of two parts, a genus name and a species name. the organisms are generally refered by either both name or perhaps more commonly the genus name to establish a category of organism. scientific names are often descriptive with significant meanings

names are given to all organisms, living and extinct, including all fossils. Many but not all organisms have common names also while common names are useful, they may less useful over large geographic areas and even less so on a world while basis,

For Example the wide spread weed Plantgo major which occurs throughout most of the world, has no less than 45 known English names, 11 French Names 75 Dutch names, 106 German names and perhaps as many as several hundred additional names worldwide.

But it has only one Binomial name Plantgo major,

DEFINITION OF SPECIES: A population of individuals capable of freely interbreeding in nature but not generally interbreeding with members of another species.

International Code of Botanical Nomenclature. 1867 group of botanist met in Paris to try and standardize rules for naming plants. Single book with rules for naming plants.

Do not specify what they are name but how they are named. All species must have a Latin description Why?

regardless of nationality, scientist all over the world can pick up a species description and read it with a knowledge of Latin

Let us trace out taxonomy and nomenclature

OTHER CATEGORIES (in between)

subdivision, subclass

subspecies, varieties and forms Some scientist recognize "super" categories Superspecies, superorder,

Never complete agreement on namesa And how to classify organisms but names are useful

Taxonomist or systematists = Person who specializes in identifying, naming and classifying things

Dichotomous Keys constructed to enable someone unfamiliar with organisms to identify them

Series of pairs of statements, choosing the correct statement that applies to the organism which then leads to two more statements. Eventually leading to the name of the organism

See keys on Pages 262-263

 

There are keys available for all types of organisms, nearly every where you go!

Keys on Local plants, Fish, insects, everything you can think of some specialist has written a key to aid in identification.

KINGDOM MONERA

 

 

 

A few Bacteria and Cyanobacteria (the Blue Green Algae) are Photosynthetic

 

REPRODUCTION

Asexual by means of fission (pinches in two) No mitosis

DNA does duplicate

No known Sexual reproduction but genetic recombination occurs in several groups facilitated by minute tubes that form connections between cells call pili

 

REPRODUCTION IN BACTERIA

NO mitosis as in eukaryotic cells

Dna and plasmid replicate and move to opposite ends of the cell. the in the middle of the cell a transverse wall forms and the cell divides in two. The cells separate and enlarge to their original size. in some bacteria the cells may remain attached to one another and form chains = Strepto or Clusters = Staphlo

 

Thousands of different Kinds of Bacteria occur primarily in 3 different forms

 

CYANOBACTERIA OR BLUE-GREEN BACTERIA (AKA BG ALGAE)

Originally algae were grouped on being photosynthetic, small, and simple organism. As we learned more about cellular detail and structure Blue Green algae were no longer considered similar to true Green Algae more nearly resembled Bacterial Cells

Less often refered to as Blue Green Algae

differences between Bacteria and Cyano

Nitrogen fixation is the ability of the organism to utilize atmospheric Nitrogen N2 and via respiration convert it in to NH4 products (ammmonia and proteins)

Cyanobacteria are often found in a mycorhizal associate with higher plants In root nodules Nitrogen fixation by cyanobacteria leads to two features of importance to Humans

 

Explain crop rotation metod and plants used. Blue Green algae live symbiotic in other organisms and lack a cell wall. when the plants cells divide their choloroplast divide if the cell contains Blue green bacteria they divide also. Speculation that all chloroplast in plant cells might have originated as Blue Green bacteria living in other cells Fossil organisms 3.5 billion years old resemble Blue Green Bacteria. Blue Green can produce substances that are toxic of higher animlas which drink water where an algal bloom has occured .

Blue Greens are generally not edible but one species in the genus Spirulina has been used for food by both African and Mexican natives for Centuries. Spirulina is very high in vitamins and now grown commercially and available in heath food stores.

KINGDOM PROTOCTISTA

 

Mobility

 

SUBKINGDOM PHYCOBIONTA

ALGAE Phycology Phycologist

Large Seaweed's, Scum on the glass of your aquarium or swimming pool human vitamins (cod liver oil) Toothpaste Sugar refining, swimming pool filters reflective paints.

ALL OF THESE ACTUALLY UTILIZE ALGAE IN SOME FORM.

 

ALGAE ARE GROUPED IN SEVERAL DIVISIONS BASED ON

 

DIVISION CHRYSOPHYTA Golden Brown Algae 4 classes in this division

Xanthophyceae Yellow Greens

Chrysophyceae Golden Browns

Bacillariophyceae Diatoms

Cryptophyceae Cryptophytes

 

While gross observation of this group would suggest they are unrelated !

They share several features to many similar features,

 

· THE DIATOMS Bacillariophyceae

 

All Diatoms - ornate appearance like glass boxes or cases.

REPRODUCTION IN DIATOMS

Unique must have adequate source of silicon in surrounding water/medium

In culture, reproduced is control by the amount silicon added to the medium

Division in culture is rhythmic, all cells dividing at the same time.

occurs this way for several generations with each new generation slightly small than the previous eventually meiosis occurs and produce gametes, these are released and fuse with other gametes = zygotes called auxospores these rapidly balloon before forming a wall and restore the diatom to normal size.

Major Ecological role

DIVISION PYRROPHYTA

Dinoflaggelates

reddish tinge to water on beaches called red tide, sudden explosion of Dino. in every cup of sea water can be highly ornate, looking like strange armor plated space ship, see page 295

· Odd!! chromosome contain 40 X DNA found in human cells? repro by mitosis, sexual is very rare some species are bio luminescent, they produce glowing blue white light when agitated (Noctoluca, Pyrocystis) Ludiferin + luciferace (enzyme) mixture produced light energy

· Used in Water quality test

· Food reserve is starch (out Chloro)

· Powerful neurotoxins due to red tides as they dye they release toxins which can accumulate in shellfish, oysters, clams, and can even kill vert. fish Dont harm shellfish but every year est. 2000 people are affected some fatal toxins so potent have been considered for chemical warfare. size of 2 periods in your text is fatal.

Global warming and red tides use to restrict to northern hemisphere as of 1990, occurring in tropical waters of So. hemisphere

EUGLENOPHYTA

THE EUGLENOIDS

barnyard pools, sewage treatment ponds

rich green bloom of algae - very active cells, one of 750 species

Euglena is the most common

some cell reproduce faster than chloroplast and produce w/o chloro will function as long as food supply is present.

Div. Cholrophyta

Green algae 7500 species

sloth has algae for camouflage backs of turtles endosymbionts in flatworms, sponges

· most common algal part of Lichens

· greatest variety is that found in freshwaters, also Ocean forms are important part of plankton, food chain.

Green algal cells resemble those of higher plants.

 

Spirogyra Water silk - most striking chloroplast known, spirally arranged within cells.

· Asexual - cell division, filaments elongate and break apart

· Sexual repro - adjacent strands form bumps called papillae, whi separates cells and fuse at tips, forming conjugations tubes.

· Protoplast condenses in one strand and moves thru tubes to fuse with stationary protoplast. Motile one refered to as male gamete stationary one - female gamete fusion = zygote zygote developes thick wall, and remains dormant for long periods generally over winter. Thick walled resting, overwintering zygotes are characteristic of fresh water algae. in Spring zygote undergoes meiosis= 4 haploid cells, three of these die only one survives to germinate in to filament

This type of sex repro is called ISOGAMY

Oedogonium

Like other filamentous, but base of filament has a hold fast cell for attachement, often occurs as epiphyte Most specialize sex repro than other green algae. short box like cells called antherida containing pair of male gametes or sperm resenble zoospores but smaller other filaments produce large round cells called OOGONIA containing 1 female gamete, called an egg. when mature, an opening or pore developes on side of oogonia male gametes are attracted to the oogonia by a chemical produced by the egg. fusions results in zygote zygote may lie dormant for long period of time, eventually undergoing meiosis and producing 4 zoospores, each of which is capable of developing in to a new filament.

This type of sex. repro is called OOGAMY

Phaeophyta - brown algae

Main food reserve is carbo - laminarian

Alginic acid or Algin makes up 40% of the dry weight of many kelp weeds.

Unlike other algae, the conspicious plant like phase of the life cycle is diploid, the inconspicious phase is haploid

Plant like Body of a kelp weed is called a thallus

Algin is commonly used as an ingredient in many products for its ability to regulate water behaviour Ice cream, salad dressing, beer, latex paints, medical suspensions, and many other products. Controls development of ice crystals in liquids regulate penetration of water in porous products stablize any kind of suspension.

Rhodophyta

RED ALGAE 5000 species are seaweeds

prefer warmer waters, from costal, to deep many grow in very low light depths few are unicelluar most are

filamentous forming branching segments and develop beautiful feathery appearance, like art work. Most are small the largest one seldom exceeding 3 feet. One sp in particular responsible for production of Agar a gelatinous substance Used in laboratories for culturing organisms and used in medical practice for capsule Many red algae show promising medicinal value for a variety of ailments including cancer treatment.

 

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