BIO exam 2 Flashcards
What type of speciation has populations that are separated by a physical barrier?
Allopatric Speciation
What is a defining characteristic of allopatric speciation?
Geographic isolation
Which of the following is an example of allopatric speciation?
White-tailed antelope squirrel & Harris antelope squirrel
Lake Victoria Cichlid
Whiptail lizards
Midas Cichlid
Cope Gray Treefrog & Gray Treefrog
White-tailed antelope squirrel & Harris
What is sympatric speciation?
A species that live in the same area
No physical barriers; new species form within the range of existing species (in direct contact)
In what ways could sympatric speciation occur?
May occur due to competition driving segments of the population to adapt to specialized niches
May occur due to niche divergence or resource partitioning
May be driven or reinforced by sexual selection
May also occur as a result of hybridization and polyploidy
Autopolyploid: due to nondisjunction (parents are same species)
What type of selection is involved with sympatric speciation?
Disruptive (divergent) selection
What are some examples of sympatric speciation?
Lake Apoyo, Nicaragua: Midas Cichlid
Lake Victoria Cichlid
Cope’s Gray Treefrog & Gray Treefrog
What type of speciation occurs when a new species is formed when two species hybridize?
Allopolyploid
What type of speciation occurs in neighboring populations that may evolve into distinct species?
Parapatric speciation
What are the five patterns of speciation related to time?
anagenesis
cladogenesis
gradualism
punctuated equilibria
extinction
What characteristic applies to both anagenesis and cladogenesis?
Speciation
What are two speculations for the origins of the universe?
Big bang
orgin of the earth
Which of these is the correct from oldest to most recent Era?
Precambrian, Cambrian, Paleolithic, Cenozoic
Cenozoic, Mesozoic, Paleozoic, Paleolithic
Cambrian, Precambrian, Paleozoic, Mesozoic
Precambrian, Paleozoic, Mesozoic, Cenozoic
Paleozoic, Precambrian, Mesozoic, Jurassic
Precambrian, Paleozoic, Mesozoic, Cenozoic
What evidence is consistent with the Big Bang Theory?
Expansion of the universe
Abundances of He, 𝐷_20, Li
Cosmic microwave background radiation
What evidence of the early conditions on Earth, are present in the reducing atmosphere?
Water Vapor
H, 〖𝑁𝑂〗_𝑥, 〖𝐶𝐻〗_4, 〖𝑁𝐻〗_3, 𝐻_2S, 〖𝐶𝑂〗_2
No free 𝑂_2
No Life
Put the following events in sequence:1. anaerobic prokaryotes evolve2. O2 present3. cyanobacteria evolve4. protocells or liposomes form, surrounding amino acids, RNA & other chemicals5. abiotic synthesis of macromolecules
5, 4, 1, 3, 2
Which of the following is NOT something that was found on the early earth (4.6BYA):
A. water vapor
B. CO2
C. small elements (H, N)
D. NH3
E. O2
E. O2
What are early compounds that were floating around in what condensed into pools of water and water vapor?
Primordial soup
What are protobionts?
Kind of molecule to form things that sort of resemble living cells but are not actually living
Precursors
What are the characteristics of early living cells?
Metabolism
Self-replicating molecules
Plasma membranes
What are the characteristics of self-replicating molecules: RNA?
- Heat + coenzymes + phosphate chains = single strands of RNA
- Ribozymes
RNA based on catalysts: able to make short copies of themselves; a sequence of bases that can make a copy of itself - NS on ribozymes
- Copying introduces errors
- More stable and faster copying variants would be more numerous (more efficient)
Ribozymes (choose all that are correct):A. are enzymes
B. are made of single-stranded RNA
C. can self-replicate
D. can digest molecules
E. are more stable than DNA
A. are enzymes
B. are made of single-stranded RNA
C. can self-replicate
What can you tell me about Plasma Membranes?
Synthesized abiotically: happens spontaneously using non-living organisms or non-living elements in the environment
Phospholipids: molecules that have a phosphate head that is hydrophilic and have a fatty acid tail that is hydrophobic
Amphipathic: hydrophilic and hydrophobic
Liposomes: sacs form spontaneously from phospholipids or vesicles
Protocells or protobionts: membrane sacs surrounding macromolecules (RNA/DNA) and metabolic agents
What can you tell me about Plasma Membranes?
Synthesized abiotically: happens spontaneously using non-living organisms or non-living elements in the environment
Phospholipids: molecules that have a phosphate head that is hydrophilic and have a fatty acid tail that is hydrophobic
Amphipathic: hydrophilic and hydrophobic
Liposomes: sacs form spontaneously from phospholipids or vesicles
Protocells or protobionts: membrane sacs surrounding macromolecules (RNA/DNA) and metabolic agents
What can you tell me about the first prokaryotes?
~3.8 BYA
Membrane-bound, self-replicating sacs of DNA and other organic molecules
Lack
No O₂; anaerobic reaction, fermentation (energy pathways)
~3.5 BYA- photosynthesis evolved in anaerobic prokaryotes
~2.5 BYA- O₂ accumulated
Cyanobacteria: transformed the atmosphere
O₂ rich atmosphere
Aerobic respiration
No further chemical origin of living cells
Ozone layer (O₃)
What can you tell me about the first prokaryotes?
~3.8 BYA
Membrane-bound, self-replicating sacs of DNA and other organic molecules
Lack
No O₂; anaerobic reaction, fermentation (energy pathways)
~3.5 BYA- photosynthesis evolved in anaerobic prokaryotes
~2.5 BYA- O₂ accumulated
Cyanobacteria: transformed the atmosphere
O₂ rich atmosphere
Aerobic respiration
No further chemical origin of living cells
Ozone layer (O₃)
What are stromatolites?
Build up in layers that form rocks that form fossils
What characteristics are involved when comparing mitochondria & chloroplasts to bacteria?
Very similar in size and structure
Have circular DNA that is replicated independently of ‘host’ DNA
Self-replicate by similar cell division
M & C have their own ribosomes which resemble those of bacteria more than eukaryotic ribosomes
Many antibiotics that kill or inhibit bacteria inhibit M & C protein synthesis
Woese and Doolittle
Contemporary endosymbiotic relationships
How did Woese determine the relationships among the 3 domain lineages:
sequenced small subunit ribosomal RNA
What made the evolution of eukaryotic cells possible by the origin of eukaryotic organelles?
Endosymbiosis
Endosymbiosis has resulted in…
The origin of mitochondria and chloroplasts
The evolution of eukaryotic cells
Horizontal gene transfers
A chimera in biology is…
an organism which has cells containing DNA from different individuals (of the same species, or of different species)
What are the 3 domains?
Archaea
Bacteria
Eukarya
Put the 3 domains in evolutionary order from the most primitive ancestral domain to the most recently evolved domain.
Bacteria, Archaea, Eukarya
What are the 6 kingdoms?
Archaebacteria, Eubacteria, Protists, Fungi, Plantae, Animalia
Which of the 6 kingdoms are prokaryotes?
Archaebacteria, Eubacteria
Which of the 6 kingdoms are eukaryotes?
Protists, fungi, plantae, animalia
What are fossils?
Mineralized proof of life (evidence of formerly living life)
What is the geologic time scale?
Transition periods based on sequences of fossils in sedimentary rocks
What are 3 examples of the geologic time scale?
Cenozoic (65 MYA-present; age of mammals)
Mesozoic (240-65 MYA; age of reptiles)
Paleozoic (570-240 MYA; age of invertebrates)
What are variants of elements with differing numbers of neutrons?
Radioisotopes
What is radio-isotope dating?
Compare the ratio of radioisotopes/stable isotopes in a sample with that of a similar living organism
What are the other types of radiometric dating of fossils?
Carbon dating
Potassium-Argon dating
Uranium-lead dating
What is taxonomy?
The science of naming things
What is the classification of organisms?
Hierarchical, attempts to reflect evolutionary relationships
What is the hierarchal order of classification of organisms?
Domain, Supergroup, Kingdom, phylum, class, order, family, genus, species
What are phylogenies?
Hypothesis: evolutionary history of relatedness of taxa
How are phylogenies constructed?
Based on shared characteristics
Morphology & homologous
structures
Genetic structure
Biochemistry
What is comparative DNA or biochemistry?
Similarities are greatest among most closely related species
What is a clade?
A grouping of related organisms
What is a cladogram?
A diagram that shows clade arrangements
What is a phylogenetic tree?
A diagram that shows the evolutionary history and evolutionary relatedness
When constructing a phylogenetic tree (or cladogram), how do scientists narrowdown the possible configurations to the most likely candidates? By:
A. the principle of parsimony
B. the fewest evolutionary events or changes required
What are the characteristics of cladistics or phylogenetics?
Uses shared homologous traits to construct diagrams
The polarity of a trait: i.e., traits that are plesiomorphic (primitive or ancestral) vs apomorphic (derived)
Clades grouped according to common ancestry
Nested
What are shared ancestral traits?
Symplesiomorphy
What are synapomorphies?
Shared derived (recently evolved) traits due to common ancestry
What are shared characteristics that are analogous, evolved independently 2 or more times?
Homoplasies
What is paraphyletic?
Does not contain all descendants
What is polyphyletic?
More than one ancestor
When describing a group of animals, you speak about an ancestral species andsome but not all of its descendants. This is an example of a
paraphyletic group
What is Occam’s razor?
The explanation that relies on the least assumptions is most likely correct
What is a phylogram?
Geological time is used to determine the relative distance of the branches
What are some general characteristics of bacteria?
Microorganisms are 0.5 to 2.0 micrometers in size
Prokaryotic, single cells
DNA: single circular chromosomes & small circular plasmids
Lack membrane-bound nucleus and organelles
What are the different prokaryotes and what membranes do they have?
Aerobic prokaryotes – respiratory membrane
Photosynthetic prokaryotes – thylakoid membrane
What are magnetosomes?
Magnetic crystals
Like a compass
Helps locate low-oxygen habits
Common in anaerobic bacteria
What helps bacteria to float?
Gas vesicles
The gram stain procedure:
. stains gram - cells pink
stains gram + cells purple
What can you tell me about cell wall: rigid?
Cell shape, physical protection, prevents lysis in a hypotonic environment
Peptidoglycan (peptides + sugars)
Some Archaeans lack cell walls, most have cell walls of proteins
What are the 3 basic shapes?
Spherical (cocci)
Rod-shaped (bacilli)
Spiral (spirillum, spirochetes)
What is glycocalyx?
Capsule (more dense, firmly attached) or slime layer (more loosely attached)
‘Mucilage’: hydrated polysaccharides and proteins, lipids and nucleic acids
Capsule/slime layer helps bacteria evade destruction by host immune cells
Mucilage: holds cells together for chemical communication: quorum sensing, DNA exchange, binding nutrients, float in water, repel attach by pathogens, glue to surfaces/form biofilms
What are biofilms?
Slime-enclosed communities of microorganisms
Resist attack by pathogens, resist antiseptic sanitizing cleaners (take time to penetrate), glue bacteria to surfaces
Function in quorum sensing
What is budding?
‘Bud’, break off a small daughter cell
What are the 3 bacterial genetic exchanges?
Conjugation
Transformation
Transduction
What is horizontal gene transfer?
DNA exchanges between different species
How does occur conjugation?
Via pilus or ‘mating bridge’
Cell-to-cell connect
Which of the following involves bacteria genetic recombination?
Conjugation
What is the F factor?
Genes that allow a cell to form pili and donate plasmids or chromosomal DNA
F+ can form pilus
F- cannot form pilus
What is transformation?
Bacteria-to-bacteria transfer
Acquired genes from another bacteria
What is transduction?
Bacteriophages transfer genetic material
Phages=virus
Virus that infects bacteria
Virus can also assist bacteria in picking up new genes
Which of the following results in the bacterial acquisition of new genes?
Transformation
What are R plasmids?
Carry antibiotic resistance genes
Frequently exchanged
Transform harmless bacteria into pathogens
What are endospores?
A thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions
What are chemoautotrophs?
Oxidize high-energy inorganic compounds to produce energy
Recycle these nutrients in the environment
Help to make certain resources available
What are chemoheterotrophs?
Decomposers; breakdown organic compounds
Carbon-based compounds
Dead stuff like animals, plants,
protists, bacteria, etc.
Examples: most pathogenic bacteria,
P. acnes, plant symbionts: fixed N
What are photoautotrophs?
Cyanobacteria
Use sunlight to create energy
Photosynthesis
What are photoheterotrophs?
Need light and organic molecules
Aerobic vs Anaerobic metabolism
Obligate aerobes: Bacteria that have-to-have oxygen (or they die)
Anaerobes: May or may not tolerate oxygen
Facultative anaerobes : Can do fermentation or aerobic respiration
Depends on if oxygen is available
