Tree Of Life Flashcards
Yeast Cell (Eukarya)
-size 8um in diameter
-some Ekarya cells are 500 um in diameter
-virus cell of Escherichia Coli (Bacteria) ~1x3 um
-1000nm = 1um in diameter
Bacteria
-Bacteria can range in size very dramatically
-most are close to 1um, but surgeonfish gut symbiont Epulopiscium (clostridia -> spores) is 600 um x 5um
Subcellular Organizations
ALL cells have
1. Cytoplasmic membrane
2. Cytoplasm containing ribosomes and metabolic enzymes
3. DNA
-some cells have walls: Bacteria, Fungi, Plants
-Animal cells have a cytoskeleton
Prokaryotic Cells
-no organelles
-no membrane-bound nucleus
Eukaryotic Cells
-internal membrane-bound organelles
-DNA within the membrane-bound nucleus
Arrangement of DNA in a Prokaryotic Cell
- DNA condensed with a “nucleoid” region
- Generally a singular circular chromosome
- Haploid
- No sexual reproduction
- Some small circular extra-chromosomal DNA “plasmid”
Arrangement of DNA in a Eukaryotic Cell
- DNA within the nucleus
- Multiple linear chromosomes
- Diploid
- Divide by mitosis
- Produce haploid gametes be meiosis
- Sexual reproduction
Viruses
-No cytoplasm, ribosome, or metabolic activity
-Not alive
Only have: 1. Nucleic acid genome (DNA or RNA)
2. Protein capsid
3. Sometimes a membrane
-must infect a prokaryotic or eukaryotic cell in order to reproduce
Classifying Life Forms
-the classical methods of classifying life forms were based on organism structure and to some degree cell structure
Early Attempts at Classisfication
Linnaeus (1753) 2 kingdoms
-Animalia (higher animals and protozoa)
-Plantae (higher plants, algae and fungi)
-no prokaryotes!
Haeckel (1865) 3 Kingdoms
-Animalia (higher animals)
-Plantae (higher plants and multicellular algae)
-Protista (all microorganisms including bacteria, protozoa, algae, molds, and yeast)
-Haeckal was a believer in Darwin’s theories of evolution and tired to present his classifications in a evolutionary tree!
What word did Haeckal invent and what does it mean?
Phylogeny = the evolutionary history of organisms
Whittaker (1969)
-Five kingdom classification of living organisms
-Monera then Protista then Plantae, Fungi, and Animalia branch off of Protista
Molecular-based approach to Phylogeny
-Carl Woese (1970s)
-16s rRNA in prokaryotes (18s rRNA in eukaryotes)
-ancient molecule that ALL cells have (part of the ribosome, essential for translation)
-changed very slowly over evolutionary time
-sequenced easily
Steps of Molecular-based approach to phylogeny
- Isolate DNA from each organism
- Make copies of rRNA gene by PCR
- Sequence DNA
- Analyze sequence
- Generate phylogenic tree
Current Phylogenic Tree of Life
-Three Domains!
-Bacteria
-Archaea (branch off of Eukarya)
-Eukarya (macroorganisms: Animals, Funi, and Plants)
-All connected by LUCA
LUCA
-Last Univeral Common Ancestor
-which diverged to two lines, one to Bacteria and one to Archea and Eukarya
Endosymniosis
Engulfing bacteria to make an interior organelle
Heterotrophs
Require organic compounds as their carbon (sugars, proteins, lipids)
Autotrophs
Utilize CO2 as their carbon source (photosynthesis, chemosynthesis)
Are energy sources and carbon sources tied together?
No
Chemoheterotrophs
Humans, many bacteria, fungi
Chemlithautotrophs
Bacteria that live in sediments, aquatic, deep sea vents
Photoautotrophs
Plants, algae, many photosynthetic bacteria
Photohetetrophs
Some photosynthetic bacteria that can use light for energy and can consume fixed carbon sources
Archaea
-Halophiles (require high salt)
-Methanogens (anaerobes, produce methane)
-Hyperthermophile (require high temp, circled)
-Extremophiles (Temp, Salt, pH) (Euryarchaeota and Crenarchaeota)
Eukarya
-Diplomonads
-Trichomonads
-Flagellates
-slime molds
-Brown algae
-Diatoms
-ciliates
-Fungi
-Red algae
-plants (green algae)
-Animals
-Diplomonads and Trichomonads don’t have mitochondria
