Diversity of Life - Mrs. Hartford Science

Diversity of Life - Mrs. Hartford Science

Diversity of Life Origin of Life Oparin Theory Urey/Miller Experiment ABIOTIC SYNTHESIS OF POLYMERS Go to Notes

History of Life The Origin of Life

To account for the origin of life on our earth requires solving several problems: How the organic molecules that define life, e.g. amino acids, nucleotides, were created? How these were assembled into macromolecules, e.g. proteins and nucleic acids, a process

requiring catalysts. How were these able to reproduce themselves? How were these assembled into a system delimited from its surroundings (i.e., a cell). Theories to Answer These Questions Abiotic Synthesis of Polymers see notes for details

1. Polymers were synthesized from inorganic compounds in the atmosphere (Urey Miller Experiment) 2. rained down on earth from outer space (Meteor analysis) 3. were synthesized at hydrothermal vents on the ocean floor (H gas)

Urey Miller

In the years since Miller's work, many variants of his procedure have been tried. Virtually all the small molecules that are associated with life have been formed: 17 of the 20 amino acids used in protein synthesis, and all the purines and pyrimidines used in nucleic acid synthesis. But abiotic synthesis of ribose and thus of

nucleosides has been much more difficult. Problem it is now thought that the atmosphere of the early earth was not rich in methane and

ammonia essential ingredients in Miller's experiments. Life from Space The Murchison Meteorite Australia on 28 September 1969, turned out to contain a

variety of organic molecules including: purines and pyrimidines polyols compounds with hydroxyl groups on a backbone of 3 to 6 carbons such as glycerol and glyceric acid. Sugars are polyols. amino acids and their relative proportions were quite similar to the products formed in Miller's experiments. Deep Sea Vents

Some deep-sea hydrothermal vents discharge copious amounts of hydrogen, hydrogen sulfide, and carbon dioxide at temperatures around 100C. These gases bubble up through chambers rich in iron sulfides (FeS, FeS2). These can catalyze the formation of simple organic molecules like

acetate. (And life today depends on enzymes that have Fe and S atoms in their active sites.) 3. Origin of Self-replicating Molecules

The discovery that certain RNA molecules have enzymatic activity provides a possible solution. These RNA molecules called ribozymes incorporate both the features required of life: storage of information the ability to act as catalysts

In the lab, the ribozyme serves as both: the template on which short lengths of RNA ("oligonucleotides" are assembled following the rules of base pairing and the catalyst for covalently linking these oligonucleotides Natural Selection in RNA

World In principal, the minimal functions of life might have begun with RNA and only later did proteins take over the catalytic machinery of metabolism and DNA take over as the repository of the genetic code. Several other bits of evidence support this

notion of an original "RNA world": Several other bits of evidence support this notion of an original "RNA world": Many of the cofactors that play so many roles in life are based on ribose; for example:

ATP NAD

FAD coenzyme A cyclic AMP GTP PROTOBIONTS Liposomes

Classification: 3 domains (20.4) Classification and Taxonomy Taxonomy = field in bio. that classifies

organisms according to presence or absence of shared characteristics to trace evolutionary relationships 5, 6 or7 kingdom (breaks down Monera and Protista more specifically) Name this scientist

Carolus Linnaeus Binomial nomenclature Genus species both italicized

Genus capitalized PHYLOGENTIC TREE (20.2) Systematics - the diversity of organisms at all levels

One goal of systematics is to determine phylogeny (evolutionary history) of a group Phylogeny often represented as a phylogenetic tree A diagram indicating lines of descent

Each branching point: Is a divergence from a common ancestor

Represents an organism that gives rise to two new groups TRADITIONAL SYSTEMICS vs MODERN CLADISTIC Traditional

Mainly uses anatomical data

Classify organisms using assumed phylogeny with emphasis on phenotype Stress both common ancestry and degree of structural difference among divergent groups Construct phylogenetic trees by applying evolutionary principles to categories Not strict in making sure all taxa are monophyletic Cladistic

Traces evolutionary history of the group under study Uses shared derived characters to:

Classify organisms, and Arrange taxa into a cladogram A cladogram is a special type of phylogenetic tree A clade is an evolutionary branch that includes:

A common ancestor, together with All its descendent species Focus on Evolutionary Classification of Monera,Protista

Plantae Prokaryotes Chapterand 21-2 and 21-3 Protista Chapter 22

Fungi - Chapter 23 Plantae - Chapter 24 Classification Classified into two Domains: Eubacteria and Archeabacteria

Kingdom Cyanobactera, Proteobacteria, etc See page 372 Classified according to nutrition, reactivity to oxygen, and divided into the two domains based on differences in their rRNA (which is really slow to change over time most likely they common from two distinct anscestors)

Autotrophic Bacteria These heterotrophic bacteria digest oil -remember oil is partially decayed plant

and animal cells Nutrition and Growth

Heterotrophic or Autotrophic Some are Photoautotrophs Use sunlight for Energy Some are Chemoautotrophs. Many are Obligate Anaerobes. Some are Faculatative Anaerobes

With or without Oxygen Ex. Escherichia Coli Some are Obligate Aerobes

Oxygen = Death Ex. Clostridium tetani Tetanus Ex.) Mycobacterium tuberculosis Temperature requirements

Some are Thermophilic, Some prefer acidic envmt. 37 Kingdom Archaebacteria

First discovered in extreme environments Methanogens: Harvest energy by converting H2 and CO2 into methane gas

Anaerobic, live in intestinal tracts Extreme halophiles: Salt loving, live in Great Salt Lake, and Dead sea. Thermoacidophiles: Live in acid environments and high temps.

Hot Springs, volcanic vents 38 Kingdom Eubacteria Can have one of three basic shapes

1. Bacilli rod-shaped 2. Spirilla spiral-shaped 3. Cocci sphere-shaped Staphylococci grape-like clusters Streptococci in chains 39

BACTERIA PICS Proteobacteria Spirochetes, Chlymydias Gram Stain

Gram-positive retain stain and appear purple Have thicker layer in cell wall. Gram-negative do not retain stain and take second pink stain instead.

Phylum Shape Motility Metabolism

Gram reacion Cyanobacteria Bacilli, Cocci Gliding, some nonmotile

Aerobic, photosynthetic autotrophic Gram-negative Spirochetes

Spirals Corkscrew Aerobic, and anaerobic; heterotrophic Gram-negative

Gram-Pos Bacilli, cocci Flagella; some nonmotile Aer/anaer.;

heterotrophic, photosynthetic Mostly grampositive Proteobacteria Bacilli, cocci, Flagella; spiral

some nonmotile Aer/anaer.; heterotrophic, photosynthetic autotrophic Gram-negative 43

Protista Endosymbiotic Theory http://www.biology87.org/apbio/diversity/Activ ity3_2005_notes.pdf

Fungus-like Animal like Amoeba Rhizopoda Foraminifera

actinopoda Plant-like dinoflagellates diatoms

Brown algae Red algae LIFE CYCLES OF PROTISTS Unicellular Green Alga Clyamydimonas

Multicellur ex. Ulva Diploid life cycle Brown Algae KINGDOM FUNGI

Overview Fungi 1. Absorptive Chemoheterotrophs 2. Decomposers 3. Study of =

mycology Ex medical mycology Characteristics

Characteristics of Fungi 1. The 80,000 species of the Kingdom Fungi are mostly multicellular eukaryotes that share a common mode of nutrition.

2. Like animals, fungi are heterotrophic and consume preformed organic matter. 3. Animals, however, are heterotrophic by ingestion while fungi are heterotrophic by absorption. 4. Fungal cells secrete digestive enzymes; following breakdown of molecules, the nutrients are absorbed. 5. Most fungi are saprotrophic decomposers, breaking down wastes or remains of plants and animals.

6. Some are parasitic, living off the tissues of living plants and animals. a. Plants are especially subject to fungal diseases. b. Fungal diseases account for millions of dollars in crop losses each year; fungal diseases also have reduced the

numbers of certain species of trees. c. Fungi also cause human diseases including ringworm, athletes foot, and yeast infections. 7. Several types of fungi are adapted to mutualistic relationships with other organisms. a. As symbionts of roots, they acquire inorganic nutrients for plants and receive organic nutrients. b. Others form an association with a green alga or cyanobacterium to form a lichen.

Lichen BASIDOMYCETES YEAST Structural Features

. 1. Fungi can be unicellular (e.g., yeasts). 2. Most fungi are multicellular in structure. a.The thallus (body) of most fungi is called a mycelium. b.A mycelium is a network of hyphae

comprising the vegetative body of a fungus. c.Hyphae are filaments that provide a large surface area and aid absorption of nutrients. d.When a fungus reproduces, a portion of the mycelium becomes a reproductive structure. Mycelium growing on fruit

3. Fungal cells lack chloroplasts and have a cell wall made of chitin, not cellulose. a.Chitin, like cellulose, is a polymer of glucose molecules organized into microfibrils. b.In chitin, unlike cellulose, each glucose has an attached nitrogen containing

amino group. 4. The energy reserve of fungi is not starch, but glycogen, as in animals.

5. Fungi are nonmotile; their cells lack basal bodies and do not have flagella at any stage in their life. 6. Fungi move to a food source by growing toward it; hyphae can grow up to a kilometer a day.

7. Nonseptate fungi lack septa, or cross walls, in their hyphae; nonseptate hyphae are multinucleated.

8. Septate fungi have cross walls in their hyphae; pores allow cytoplasm and organelles to pass freely. 9. The septa that separate reproductive cells, however, are complete in all fungal groups. Hyphae with septa are called septate hyphae

Hyphae without septa are called coenocytic hyphae REPRODUCTION Fungi Phylogeny Plant Evolution and Classification

Chapters 24 Key Concepts Plants moving from water to land Classification of plants

Alternation of generations Plant Characteristics Challenges to life on land Challenges to life on land Challenges to life on land

Challenges to life on land Challenges to life on land Focus on Mosses TheGametophyte Generation

The leafy shoot of mosses is haploid and thus part of the gametophyte generation

Mosses: continued three kinds of shoots: female, which develop archegonia at their tip;

male, which develop antheridia at their tip;

A single egg forms in each archegonium. Multiple swimming sperm form in each antheridium. sterile, which do not form sex organs.

Mosses: continued In early spring, raindrops splash sperm from male to female plants. These swim down

the canal in the archegonium to the chamber containing the egg. The resulting zygote begins the sporophyte generation.

Mosses: continued The Sporophyte Generation Mitosis of the zygote produces an embryo that grows into the mature sporophyte generation. It consists of:

a foot, which absorbs water, minerals, and probably some food from the parent gametophyte. a stalk, at the tip of which is formed a sporangium.

Mosses: continued The sporangium is filled with spore mother cells sealed by an operculum, and covered with a calyptra. The calyptra develops from the wall

of the old archegonium and so is actually a part of the gametophyte generation. It is responsible for the common name ("haircap moss") of this species.

Mosses: continued During the summer, each spore mother cell undergoes meiosis, producing four haploid spores - the start of the new gametophyte

generation. Late in the summer, the calyptra and operculum become detached from the sporangium. Low humidity causes the ring

of teeth within the opening of the sporangium to pop outward ejecting the spores. Mosses: summary

These tiny spores are dispersed so effectively by the wind that many mosses are worldwide in their distribution. If a spore reaches a suitable habitat, it germinates to form a filament of cells called a protonema. Soon

buds appear and develop into the mature leafy shoots. The gametophyte generation is responsible for sexual reproduction The sporophyte generation is responsible for dispersal.

http://www.sirinet.net/~jgjohnso/ lifecyclesplants.html Classification Non-vascular vs. vascular

What does vascular mean? Xylem= transports water from roots to rest of plant Phloem= transports sugars and nutrients throughout plant Classification

Seedless vs Seeds What is a seed?

Plant embryo packaged with a store of food within a resistant coat http://www.sirinet.net/~jgjohnso/lifecyclesplants.html PLANT STATIONS

I. Bryophytes II. Ferns III. Pine Life Cycle IV. Angiosperms

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