Lecture 9/8- Systematics CH 12

Intro

• 2 sciences

• Taxonomy

• Science of classification

• Science of nomenclature

• Systematics

• Science of relationships

• Science of phylogeny (evolution)

Taxonomy

• based on ranks

• Forms hierarchy

• Kingdom

• Division

• Class

• Order (-ales)

• Family (-aceae)

• Genus

• Species

Inclusive to exclusive (on way down)

Exclusive to inclusive (on way up)

Taxonomy gives names (nomenclature)

Modern nomenclature

• Carl Linnaeus

• Organisms consist of genus and specific epithet= species name

• Hence binomial system

Systematics

• gives relationships

• how different taxonomic ranks relate

• Currently implies evolution

• Based on homology not analogy

Taxa should be based on phylogeny

• Evolutionary descent

• Derivation from single common ancestor

• monophyletic vs polyphyletic

• Single branch vs multiple branch

Species Name consists of:

• Genus and specific epithet

• What is a species?

• Biological species concept

• Group of interbreeding populations

• Reproductive isolations

• Problems?

• Hybrids (Quercus- oaks, Fraxinus- Ashes)

• Asexual organisms (bacteria, algae)

• Analogous structure (A question)

• Wings

Major Groups of Organisms

• From molecular, anatomical, and morphological data

• 2 main groups

• Prokaryotes

• Eukaryotes

• 3 domains of life

• Bacteria (Pro)

• Archaea (Pro)

• Eukarya (Eu)

• Molecular data suggests

• Over 17 kingdoms of prokaryotes

• Over 50 kingdoms of eukaryotes

• Make life simple

• 6 kingdom system

• 2 kingdoms of prokaryotes

• Eubacteria

• Archaebacteria

• 4 kingdoms of eukaryotes

• Protistans

• Animals

• Plants

• Fungi

Prokaryotes

• first cells to evolve

• Characteristics

• DNA free in cytoplasm

• Lack membrane bounded organelles

• Lack microtubules

• No 9+2 flagella or cilia

• No mitosis

• Haploid

• 1 chromosome

• No sexual reproduction (meiosis)

• No multicellularity

• Small (70S) ribosomes

• Over time 2 distinct lineages evolved

• Archaea

• Refers to habitats that they grow under

• Methogens, halophiles, thermophiles

• Younger of two

• Eubacteria

• Elder of the two

• Both groups underwent serial endosymbiosis

• Cell from archaea “host”

• Mitochondria/chloroplast from eubacteria

Eukaryotes

• nucleus

• Endosymbiosis

• Characteristics

• DNA bounded

• Membrane bounded organelles (optional)

• Microtubules

• 9+2 flagella or cilia

• Mitosis

• Haploid or diploid

• Sexual reproduction (meiosis) (only if diploid)

• May or may not be multicellular

• Large (80S) Ribosomes

• Evolution of nucleus lead to kingdom Protista

• from kingdom Protista several divisions evolved

• Cellular differentiation

• Multicellular organisms

• Several lineages evolved

• Fungi

• Plantae

• Animalia

Lecture 9/8- Prokaryotes CH 13

• Oldest group of living organisms

• Over 3.5 billion years old

• Structurally simple

• Lack nucleus

• Lack endomembrane systems

• Biochemically complex

• Nutritional modes

• Autotrophs

• Photoautotroph

• Chemoautotroph (deep sea vents)

• Heterotrophs

• Ecology

• Ubiquitous (everywhere)

• How?

• O2 requirements

• Aerobes (Oxygen is Final electron acceptor in cellular respiration)

• Microaerophiles (Small amount of O2)

• Facultative anaerobes (Can grow in O2)

• Obligate anaerobes (die in O2)

• Ecological roles

• Producers

• Recyclers (Saprobes)

• Symbionts

• Commensalism (1 benefits)

• Epiphytes

• Mutualism (2 benefits)

• Lichens

• Jellyfish/flashlight fish

• Parasitism (1 benefits at others expense)

• Strep throat

• Soft rots

• Fire blight

• Reproduction

• Binary fission

• No spindle apparatus or microtubules

• Fragmentation of colony

• No meiosis

• Gametes never produced

• Haploid only

• Genetic exchange?

• Conjugation (direct contact)

• Transduction (via virus)

• Transformation (naked DNA)

Morphology

• Cell shape

• Bacillus

• Coccus

• Spiral

• May or may not have sheath

• Mucilaginous covering

• Cell wall composition

• Peptidoglycan

• Pepti- protein

• Glycan- sugar

• Subunits

• NAG

• May or not have NAM (Eubacteria has it) (Archeae may or may not have it)

• May or may not have pigmentation

• May or may not have pili + fimbriae (attachment)

• Fimbriae attach to substrate

• Pili to other cells for conjugation

• May or may not have flagella (non-microtubular)

• Anatomy

• Plasma membrane

• Ribosomes

• Inclusion bodies

• Nucleoid

• Single circular chromosome

• Ribosome free area in the cytoplasm

• Plasmids

• Extrachromosomal DNA

• Exists as small circular pieces

• R-factors (resistance)

Autotrophic photo systems found in plasma membrane

Kingdoms

• Archaea

• Diverse group of organisms

• Name refers to habitats, not age

• Organisms found in primitive/old habitats

• Characteristics

• rRNA sequence- eukaryotic like

• Lipids of plasma membrane unique

• Cell walls lack muramic acid

• Primarily autotrophs

• Major groups

• Methanogens

• Anaerobic chemoautotrophs

• Produce methane from respiratory pathways

• Found in swamps, bogs, marshes, deep oceans, ruminants

• Swamp Gas

• Halophiles

• High salt concentrations (12-23%)

• Found in salt lakes, salt domes

• Photosynthetic

• Rhodopsin

• Hence the red color

• Prefer high temperatures

• 30-50 Celsius

• Thermophiles

• Heat lovers

• 70-105 Celsius

• Sulfur users

• Chemoautotrophs

• Found in hot springs, thermal vents

• Eubacteria

• Characteristics

• RRNA 30s + 50s

• Both autotrophic and heterotrophic

• Cell wall contains muramic acid

• Two main types

• Gram +- thick cell wall

• Gram - - thin cell wall

• Two divisions

• Schizobacteria

• Heterotrophs

• Regular bacteria

• Cyanobacteria

• Autotrophic

• “Blue-green” algae

• Cyanobacteria

• Found: water, soil, rock, turtle shells, 3-toes sloth

• 7,500 species- most in symbiotic relationship

• 200 species that are free living

• Symbiotic relationships:

• Plants -cycads

• Protists

• Animals

• Fungi - lichens

• Energy stored as glycogen

• Pigments

• Chlorophyll a

• Chlorophyll b

• Phycobilins

• Phycocyanin-blue

• Phycoerythrin- red

• Pigments found in photosystems

• Highly folded plasma membrane

• Colors: blue, green , blue-green, red

• Other colors: Black, olive, violet

• How?

• Structural, sometimes color is in the sheath

• Morphologies

• 3 basic cell shapes

• Can form colonies

• Nostoc-colony in collective sheath

• Can form filaments (chain)

• Branching pattern true or false

• Can act as propagation unit

• Separation disk

• Hormogonium

• Can be buoyed by gas bubbles

• Lack flagella

• Other specialized cells

• Heterocysts

• N-Fixation

• Thick cell wall with indentations

• Akinetes

• Survival

• Thick cell wall + dense cytoplasm

• Other autotrophic Eubacteria

• Sulfur users

• Green sulfur bacteria

• Purple sulfur bacteria

• Chlorophyll a + carotenoids

• Hydrogen sulfide used instead of water to recharge photosystem

• CO2 + H2S >> CH2O +H2 +S

• Non Sulfur users

• Purple non sulfur bacteria

• Mitochondria

• Various compounds used as electron donors during photosynthesis

• Few Species edible

• Nostoc, spirulina

FUNGI

• Kingdom contains variation in growth forms and life cycles

• What ties them together

• Primarily grow as threads

• Hypha (e)

• Mycelium

• Nutrition

• Heterotrophic by absorption

• Spores

• Walled reproductive structures

• Sexual and asexual reproduction

• Cell wall composed of chitin

• Food reserve glycogen

• Ecological Roles

• Recyclers/decomposers

• Symbionts

• Parasites

• Plants

• Tomato Wilt

• Cedar apple rust

• Wheat rust

• Animals

• Ringworm

• Athletes foot

• Mutualism

• Lichens

• Mycorrhizae (fungus roots)

• Fungus acts as root hairs-absorbing

• Plant gives food to fungus

• Fungus gives water back to plant

• Association common

• Thought that mycorrhizal associations allowed colonization of land

• Soils poorly formed, if it all

• Fungi able to use it

• Protect autotroph

• Drying out

• Reproduction

• Asexual

• Zoosporangia with zoospores

• Chytridiomycota

• Sporangia with spores

• Zygomycota

• Conidiogenous cells with conidia

• Ascomycota

• Basidiomycota

• Sexual

• Gametes

• Chytridiomycota

• Gametangia

• Zygomycota

• Specialized cells

• Ascomycota

• Basidiomycota

Chytridiomycota

• Chytrids

• 800 species

• Aquatic to terrestrial habitats

• 1 flagellum on reproductive cells

• Growth form

1. Unicellular

2. Hyphal

• Coenocytic (multiple nucleus)

• Reproduction

1. Asexual

• Zoospores in zoosporangia

2. Sexual

• Various types

• Anisogamy

• Female gametangium >> large gamete

• Male gametangium >> small gamete

• Zygote >> biflagellated

• Importance

1. Recycling

2. Decomposers

3. Pathogens

• Synchytrium on onion/potato

• Biocontrol of mosquitos

4. Chytridiomycota is decimating frogs/salamanders populations world wide

5. Of the app. 500 species attacked by fungus

• 90 species extinct

• 124 species have had populations reduced by more than 90%

• That’s about 7% of the amphibians

• Started in late 1980s

• Make sure you know life cycle of chytrids **

Zygomycota

• 1100 species

• Terrestrial

• AFlagellate

• Hyphal        (coenocytic)

• Reproduction

• Asexual

1. Spores in sporangium

• Sporangium on sporangiophores

2. May or not may see columella (clear)

• Sexual

1. Thick wall zygospore by conjugation

• Gametangium contact

• Often ornamented

2. Compatible hyphae grow towards each other

3. Progametangia make contact (conjugation)

4. Lay down septa, gametangia produced

5. Plasmogamy and karyogamy

6. Zygospore maturation

• Importance

• Recyclers and decomposers

• Pathogens

• Biocontrol of insects

1. Entomophthorales

• Bread and fruit rots

• Commercial uses

1. Cheeses

2. Tempeh

3. Soy sauce

4. Drugs

5. Yellow coloring

• Go over Life Cycle ***

Ascomycota

• Sac fungi

• 32,000 species

• Terrestrial

• AFlagellate

• Growth form

• Septate hyphae

• Some unicellular (yeasts)

• Life cycle twist

• Dikaryon (two nuclei in cell) (n+n)

• Haploid cells fuse

• Haploid nuclei do not go through karyogamy immediately

• Reproduction

• Asexual

• Conidia on

• Conidiogenous cells on

• Conidiophores

• Budding (yeasts)

• Asexual reproduction common most species have it

• Sexual

• 8 ascospores in

• Ascus in

• Ascocarp

• Fertile layer called hymenium (reproductive structures on it)

• Dikaryon produce by

• Ascogonium

• Female

• Produces trichogyne

• Antheridium

• Male

• Trichogyne grows to fuse ascogonium and antheridium

• Importance

• Morels and truffles

• Drugs

• Fermentation (bread and beer)

• Impact:

• Animal- athletes foot

• Plants- Dutch elm disease

• Chestnut Blight

• Ergotism

• Poisoning by fungi

• St. Anthony’s fire

• Ergotine

• LSD

• Salem Witch Trials

• Biocontrol of insects

Basidiomycota

• Club Fungi

• 23000 species

• Terrestrial

• AFlagellate

• Growth form

• Septate hyphae

• Clamp connections

• Morphology

• Reproduction

• Asexual (rare)

• Conidia on

• Conidiogenous cells on

• Conidiophores

• Sexual

• 4 basidiospores on

• Sterigmata on

• Basidia on

• Basidiocarp

• Importance

• Food

• Shiitake, puffballs, oysters, button mushrooms

• Toxins

• Destroying angel, hallucinogens

• Life cycles

• Most follow 1n>n+n>2n

• Dikaryon can last decades

• Know life cycle**

• Rust

• Some have complicated life cycles

• Alternate hosts

• 5 spore types

• Rusts

• Host: American barberry

• Structures and spores produced

• Spermogonia produce spermatia (upper leaf surface)

• Acecia produce aeciospores (lower leaf surface)

• aeciospores Go to wheat

• Host:

• Uredinia produce urediniospores**

• Telia produce teliospores (black) **

• Basidia produce basidiospores

• Basidiospores go to American barberry

• Know the cycle **

• Uredospores not pointed , not bi cell , crinkled

• Telia spore pointed , bi cell , smooth

• Deuteromycota

• Fungi Imperfecti (imperfect fungi)

• About 15000 species

• “Molds + mildews”

• Reproduction only asexual

• Sexual stage is extremely rare

• Deuteromycota was/is a dumping ground for species of fungi that reproduce primarily by asexual reproduction

• Can either be Ascomycota or Basidiomycota

• Most Ascomycota

• How to tell ?

• Basidiomycota have clamp connections

• Asexual reproduction very advantageous

• Quick

• Little energy involved

• Adapted to environment

• Molds vs Mildews?

• Lichens

• Symbiotic relationship with fungi and algae

• Fungi — mycobiont (usually Ascomycota)

• Algae — phycobiont (usually chlorophyta, Cyanobacteria)

• Importance

• Primary colonizers — soil formation

• Pollution indicators

• Dyes

• Food

• Antibiotics

• Pharmaceuticals

• 3 morphologies

• Crustose- crusts

• Foliose- leafy

• Fruticose- shrubby

• Reproduction

• Fragmentation

• Soreidia

• Hyphae wrapped around algal cell