Biodiversity Flashcards
Phylogeny
A group of related species
What are the hiearchical classifications in order?
- Domain
- Kingdon
- Phylum
- Class
- Order
- Family
- Genus
- Species (can interbreed)
What is binomial nomenclature? Who was it invented by?
- Naming organisms by their genus and then their species name.
- Polar bear (Ursus Maritimus), Grizzly bear (Ursus Horribilis)
- It was invented by C. Linnaeus
What is a phylogenetic tree?
- A representation of the evolutionary history of a group of organisms.
- Built according to morphology, genetics, and the behavioral traits of organisms
What is a clade?
A group of organisms that will include an ancestor and the descendants of that ancestor.
What is a homologous structure?
- Share a common ancestor
- Structures may resemble one another
- Morphological divergence
- They might not perform the same function
- Think bat wing vs whale fin, or Arm of a human vs a bird’s wing
What is an analogous structure?
- No common ancestor NB!!!!
- Similar in appearance and structure
- Perform the same function
- Think fins of a fish vs fins of a whale, or wing of a dragonfly vs wing of a bird
Molecular Clocks
- Methods used to measure evolutionary change
- Based on the idea that some parts of the genome appear to evolve at constant measurable rates.
- Some genes will evolve thousands or even millions of times faster than another
- Mutation rates are noted and conclusions of when species diverged can be formed.
Eukaryotes vs Prokaryotes
- Nucleus:
- E: Nucleus houses the genetic material
- P: No nucleus, but contains DNA and RNA
- Cytosol
- E: Contains cytosol
- P: Contains cytosol, it has a special portion with DNA floating in it called the nucleoid
- Ribosomes
- E: Contain ribosomes all over the place
- P: Contain ribosomes in the cytosol, but they are smaller
- Organelles:
- E: Contain many diverse organelles
- P: Doesn’t contain any membrane bound organelles. They do contain vacuoles and ribosomes. Cyanobacteria have free floating chlorophyll vs a chloroplast
- Cytoskeleton:
- E: Present
- P: Flagellum is present, but composed of only one fiber. Rudimentary cytoskeleton. May be absent
- Cell Membrane
- E: Plasma membrane with steroid
- P: usually no steroids
- Nucleolus
- E: yes
- P: No, lacks membrane bound organelles
- Cells
- E: Multicellular (usually)
- P: Unicellular (usually)
- Cell Wall
- E: Only in fungi, protists, and plants but not in animal cells. Chemically simple
- P: In all. Chemically complex
- Types
- E: Animals, insects, hydra, plants, fungi, etc.
- P: Bacteria and Archaea
What was the first organism to inhabit the earth?
Anaerobic heterotrophic prokaryotes
How old is earth? How old are Prokaryotes? How old are Eukaryotes?
Earth is 4.5 billion years old
Prokaryotes are 3.5 billion years old
Eukaryotes are 2.5 billion years old
What kind of atmosphere did early earth have?
A reducing atmosphere. It lacked O2. It contained CH4, H20 vapor, H2, CO, and HCN
How did earth gain O2?
Partly from cyanobacteria. Studies are still ongoing.
What range of shapes do prokaryotes take?
- Coccus:
- Diplococci - may be in pairs or singly
- streptococci - may be in chains
- staphylococci - may be in clusters
- Bacilli - Rod shaped
- Spiral
What kingdom do prokaryotes belong to?
Monera
How do prokaryotes reproduce?
They divide by binary fission. Asexual reproduction
They are highly successful because they can reproduce rapidly given favorable conditions. a new generation can appear in under a half hour
Taxis
Many use flagella to move.
+ chemotaxis: bacteria moves towards food
- chemotaxis: bacteria moves away from a toxin
Pilli
Protein filaments used to attach to cell surfaces or even to each other during conjugation
conjugation
When two bacteria join together by pilli and swap plasmids with each other.
plasmid
- Circular DNA that is separate from the main chromosome.
- Contains genes that can benefit the organism (eg. drug resistance)
- F-Plasmids: contain tra genes that allow for conjugation
- R-Plasmids: contain genes for resistance against poisons or antibiotics
- Plasmids can belong to multiple groups. NB
Bacteria Mutualism in humans
E. Coli in the large intestine helps break down food and form vitamin K. We allow them to live and give them food, while they provide us with vitamins
What are some bacterial diseases?
- Anthrax
- Sepsis
- Salmonellosis
- leprosy
- Syphilis
- Gonorrhea
What are the three main groups of Archaea
- Thermophiles: Love heat. Live in sulfur rich hot springs. Almost all are obligate anaerobes. They die if exposed to O2. They use Sulfur as their electron donor.
- Methanogens: Make CH4 gas. Live in swamps. Live in the stomach of ruminants(can digest cellulose) like cows. rod shaped and cocci are noted. They are chemo autotrophs: Use H2 as an electron source for reducing CO2 and CH4 gas
- Extreme Halophiles: They love salty brackish habitats like the dead sea. Most produce ATP aerobically, but when O2 is low some strains will use sunlight for photosynthesis.
Prokaryotic Metabolism
- They carry out glycolysis and are capable of additional reactions
- They can use an electron transport chain to produce ATP
- Anaerobic bacteria live by using different electron acceptors such as NO3- or SO4-2 at the end of their ETC
- Phototrophs obtain energy from sunlight
Prokaryotes and gas cycles
- Prokaryotes decompose plants and animals, which returns CO2 to the atmosphere.
- Methanogens produce CH4, which can eventually be oxidized to CO2. Clearly, they are vital to the Carbon Cycle
- Prokaryotes also fix atmospheric Nitrogen, where it is converted into NH3. Nitrogen fixation is essential for the biosynthesis of essential molecules in plants and other life forms. Their role in the Nitrogen cycle is enormous. The nitrogen fixing bacteria are found in root nodules
Gram + vs Gram - bacteria
- Peptidoglycan layer (cell wall)
Gram - : Thin peptidoglycan layer (cell wall) that poorly stains red or pink, but when washed with an alcohol solution does not retain it.
Gram + : Thick peptidoglycan layer (cell wall) that stains purple and retains the stain when washed with alcohol solution.
Gram + vs Gram - bacteria
- Teichoic acids
Gram - : No teichoic acids
Gram + : Usually have teichoic acids that provide rigidity to cell wall, and provide binding sites for cations
Gram + vs Gram - bacteria
- Outer membrane
Gram - : No outer phospholipid bilayer
Gram + : Two phospholipid bilayers sandwich a smaller cell wall (peptidoglycan layer)
Gram + vs Gram - bacteria
- Lipids and Lipoprotein
Gram - : High lipids and lipoprotein content
Gram + : Low amount of lipids and lipoprotein
Gram + vs Gram - bacteria
- Antibiotic resistance
Gram - : Much more resistant to antibiotics due to the outer phospholipid bilayer.
Gram + : Less resistant, thus more susceptible to antibiotics
Gram + vs Gram - bacteria
- Pathogenic
Gram - : Can be pathogenic
Gram + : Can be pathogenic
Are Archaea pathogenic?
NOOOOOOO!!!!!!!!
Gram + vs Gram - bacteria
- Capsule
Gram - : Have an outer capsule
Gram + : Have an outer capsule
Viruses
- No cells or organelles
- Contains either DNA or RNA, but never both
- Consists of capsid (protein coat), Nucleic acid core (DNA or RNA (called a retrovirus)), and sometimes a membranous envelope
- Many shapes are possible: polyhedral, circular, filamentous
- smaller than a ribosome
- Need a host to reproduce (obligate intracellular parasites)
- Possess a limited host range
What is a retrovirus?
A virus that contains RNA instead of DNA
What are the two ways that viruses can reproduce in a bacteriophage? What are the differences?
Lytic cycle
- Bacteriophage inserts its DNA into a bacterial cell.
- The DNA causes the host DNA to deteriorate and then the virus DNA is used to create proteins of progeny viruses.
- The DNA replicates and the proteins are assembled with the DNA to form progeny.
- The cell lyses and the virus progeny go on to infect another bacteria.
Lysogenic cycle:
- Bacteria inserts its DNA into a bacterial cell
- The viral DNA incorporates into the host DNA. This DNA is referred to as a prophage
- The bacteria replicates passing the prophage on to its progeny
- At some point an event occurs, chemical, radiation, etc that triggers the lytic phase to occur.
- The DNA causes the host DNA to deteriorate and then the virus DNA is used to create proteins of progeny viruses.
- The DNA replicates and the proteins are assembled with the DNA to form progeny.
- The cell lyses and the virus progeny go on to infect another bacteria.
Virulent
The damage done to the host cell. The more damage the more virulent.
The lytic cycle is more virulent than the lysogenic cycle.
prophage
The DNA that is incorporated into a bacterial cell during the lysogenic cycle
What are some examples of DNA and RNA viruses
DNA
- herpes
- small pox
- cow pox
RNA
- HIV
- Coronavirus
How do RNA viruses pass their genetic material to the host
The mRNA is passed into the cell and is transcribes its RNA into cDNA using reverse transcriptase.
The cDNA is then incorporated into the genome and is transcribed normally and then translated into the viral proteins
Viroids
- Circular RNA molecules devoid of a protein coat
- Smallest infectious pathogen known!
- Seen in plants mostly >99%
- Only human disease caused by a viroid is hepatitis D
Prions
- Infectious protein that are involved with causing proteins to fold incorrectly
- The misfolded protein passes on the same misfolding to other proteins
- Ex: Mad Cow disease, Scrapie in sheep and goats, Kuru, and Creutzfelt-jacob Disease.
- Can’t be killed by cooking
- No cure, so always fatal
Obligate anearobe
killed by O2
Obligate aerobe
need O2 to grow and live
Facultative anearobe
prefers O2 if around, but can switch to fermentation if needed
Photoautotroph
Use light for photosynthesis. CO2 is used to make organic molecules like sugar.
Cyanobacteria, plants, and algae
Chemoautotroph
Seen in prokaryotes
CO2 is the carbon source, but an inorganic substance is an energy source. H2S, NH3, or even Fe+2 are oxidized. No light needed.
Photoheterotroph
Light is needed for ATP production, but gets their carbon from various organic sources like fatty acids or carbohydrates that other organisms produced
Chemoheterotroph
Energy is obtained from organic compounds.
Bacteria, Fungi, most protists, and animals are here.
What are the two main decomposers?
Bacteria and Fungi
detritivore
Bacteria and Fungi decompose the matter into smaller units. A detritivore then consumes the smaller units for energy.
worms, slugs, lice, etc
