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