Bio 2 - Unit 1 Flashcards
What is the force of evolution that is the source of all new alleles in a given population?
Mutation
What is the force of evolution that is the main force behind adaptation?
Natural Selection
What is the force of evolution that can both lower and increase gene diversity?
Gene Flow
What is the force of evolution that randomly decreases the gene pool (usually via natural disasters)?
Genetic Drift
What is the force of evolution that facilitates secondary sexual characteristics and nonrandom mating?
Sexual Selection
What is convergent evolution?
Convergent evolution is the selection of adaptations in an environment. Natural selection favors certain adaptions, so those adaptions will appear in multiple species that may not be related.
What is an ancestral similarity?
It is a similarity between species that is from the most recent common ancestor of that group/clade. Present in the common ancestor itself.
What is a derived similarity?
A similarity between species that is exclusive to a select few of a group/clade. Common ancestor may or may not have this characteristic.
What is polarization?
The decision whether some character states are ancestral or derived.
What is an outgroup?
An outgroup is a species closely related to the group in study (but not a part of that group).
What is outgroup comparison?
If the outgroup chosen has similar characters to the group in study, then the character is ancestral and vice versa.
What is a clade?
A group with a common ancestor and ALL of its descendants.
What other term can be used to describe a clade..?
A monophyletic group.
What is homoplasy?
A derived characteristic resulting from convergent evolution or evolutionary reversal. Not present in the common ancestor.
What is the acronym for all 8 taxa?
Did King Phillip Come Out For Good Socks?
What are all 8 taxa?
Domain
Kingdom
Phyla
Class
Order
Family
Genus
Species
How does the PSC/LSC constitute a species?
Species are groups of populations evolutionary independent from other groups. Lineages are species.
What are the 3 types of phyletic groups?
Monophyletic
Paraphyletic
Polyphyletic
What is homology?
Passing of a structure from a common ancestor to its descendants.
Homology vs. Homoplasy
Homology results in homologous structures in a descendant of an ancestor.
Homoplasy results in analogous structures in different species (likely from convergent evolution).
What is a monophyletic group?
A group of a common ancestor and all descendants. AKA clade.
What is a paraphyletic group?
A group of a common ancestor, and some descendants.
What is a polyphyletic group?
Does not include a common ancestor. Some species are grouped together based on traits. Species may be far apart on the phylogenetic tree.
What is the basic structure of viruses?
A DNA/RNA genome encased in a protein capsid.
What are naked viruses?
Viruses without an outer lipid envelope.
2 basic shapes of viruses:
Helical - rod like
Icosahedral - geometrical, roundish, like the dice.
What are the two reproductive cycles of viruses?
Lytic and Lysogenic
Processes of Lytic Cycle
Attachment, Entry, Replication, Assembly, Release
Process of Lysogenic Cycle
Virus enters, inserts its genome, cell replicates genome and infection starts.
Prophage is:
Inserted genome from virus during Lysogenic cycle.
Lysogens are:
Infected cells during Lysogenic Cycle.
What is a temperate phage?
A phage that can enter both reproductive cycles.
What are viroids?
Naked strands of RNA. Tends to infect plants.
What are prions?
Infectious strains of proteins.
What types of viruses (genetic) infect animals, plants, and bacteria?
Animals are infected with both RNA and DNA strands of viruses.
Plants are infected with RNA based viruses.
Bacteria are infected with DNA based viruses AKA bacteriophages.
Bacteriophage
A virus that exclusively infects bacteria with a head-tail morphology.
What is sexual dimorphism?
The differences in males and females of a species.
What is the relation of size in prokaryotes compared to eukaryotes?
Prokaryotes are much smaller.
True or False: prokaryotes have membrane bound organelles.
False
Which prokaryotes (Archaea/Bacteria) have ether linkages in their PM?
Archaea
Which prokaryotes (Archaea/Bacteria) have ester linkages in their PM?
Bacteria
What are the purpose of cell walls in bacteria?
To prevent bursting of the cell.
Archaea lack _____ in their cell walls. They instead have _____ in their cell walls.
Peptidoglycan; Pseudomurein
What is an S-layer? Which domain is it universal in and why?
An extra protein layer outside of the membranes. Universal in Archaea to help them survive extreme environments.
What are capsules? What are slime layers?
Capsules are gelatinous layers surrounding other cell wall layers. Slime layers are capsules that are harder to detect.
What are endospores?
Almost like a state of being where bacteria enter when environment is too harsh. They are nearly indestructible.
3 types of horizontal gene transfers.
Conjugation (cell contact)
Transduction (virus injection)
Transformation (plasmids from environment)
What are the 3 main shapes of bacteria?
Bacili, Cocci, Spirilis
What is the extra shape of bacteria not of the main 3?
Virbrios - comma shaped or beans
What is horizontal gene transfer?
The spreading of genetic material across multiple species or cells of prokaryotes.
What do bacteria do during nitrogen fixation?
They convert atmospheric N2 to NH3. Ammonia is an easier form of nitrogen to use for many organisms. N2 has a tough triple covalent bond to break.
What is phagocytosis?
The engulfment of pathogens by phagocytes (good) leading to pathogens’ death.
What is the human microbiome?
The collective population of bacteria in a human.
Bioremediation is:
The usage of prokaryotes to lessen pollution.
Assortative Mating is:
Positive assortative mating is:
Negative assortative mating is:
Assortative mating is the nonrandom mating based on phenotypes.
Positive AM is choosing mates based on similar phenotypes (relative to chooser).
Negative AM is choosing mates based on different phenotypes (relative to chooser).
Intrasexual selection is:
The competition between, usually, males. Males will fight to assert dominance.
Intersexual selection is:
The ‘choosiness’ of females towards male mates.
What leads to intersexual selection?
The parental investment of females is greater than males.
What is stabilizing, directional, and diversifying/disruptive selection?
Stabilizing - the selection for intermediate phenotypes.
Directional - the selection for one phenotype or the other.
Diversifying - the selection for two extreme ends of a phenotype.
What is negative frequency dependent selection?
The selection FOR individuals with outlier phenotypes. These individuals will be ignored by predators looking for the common phenotype.
What is positive frequency dependent selection?
The selection AGAINST individuals with outlier phenotypes. These individuals will be picked off because they stand out.
Negative frequency dependent selection leads to…
More genetic variation.
Positive frequency dependent selection leads to…
Less genetic variation.
Biological Species Concept states a species is a species because…
Populations that interbreed and produce viable offspring and species.
Prezygotic and postzygotic barriers are things that influence the BSC because…
They prevent the inbreeding of certain populations which leads to the classification of different species.
Allopatric Speciation is…
The differentiation of populations due to geographic isolation.
Sympatric Speciation is…
The differentiation of individuals in a population in the same area. Same place speciation due to allopolyploidy or autopolyploidy.
Fusion of species is a result of what?
The result of gene flow countering speciation. Fusion of species is due to incomplete reproductive isolation barriers.
What are reservoir species?
The natural hosts of a virus that do not contract symptoms of said virus.
What are viral vectors?
Spreaders of a virus (usually bugs).
What are the enzootic cycles and epizootic cycles of disease?
Enzootic - the regularly active disease which affects organisms in a place or season.
Epizootic - the temporarily prevalent and widespread disease.
Pili in bacteria are similar to ___ in protists.
Cilia
What is bacterial mucilage?
Sticky secretion of bacterial cells. Used for biofilms to adhere colonies.
What are some defining traits of Gram Positive Bacteria?
Stained purple, high amounts of peptidoglycan in cell walls, vulnerable to penicillin.
What are some defining traits of Gram Negative Bacteria?
Stained pink, low amounts of peptidoglycan in cell walls, resistant to penicillin, presence of lipopolysaccharides in cell walls.
Cyanobacteria are:
Photosynthetic bacteria that are diverse in their multicellular structure.
Proteobacteria are:
Heterotrophic Bacteria.