Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
eras of increased complexity (notable groups/changes, time frame of eras) |
Neolroterozoic (1 bill-542mya): sponges, cnidarias, soft-bodied multicellular prokaryotes
Paleozoic (542-251mya): hard, mineralized skeletons, arthropods, echinoderms, chordates
Mesozoic (251-65.4mya): animal groups already developed spread to new habitats and adapted. dinosaurs and first mammels
Cenozoic (65.5mya-now): large mammels filled empty niches, and with cooling climate new adaptions arose |
|
|
|
Eons (oldest to newest, time frame and notable characteristics) |
Hadean(4600-3850mya) - super hot, formation of earth (crust, atmosphere, oceans) no life
Archaean (3850-2500 Mya) - prokaryotes
Proterozoic (2500-542 mya)- O2 in atmosphere, eukaryotes, multicellularity
Phanerozoic (542mya- now), diversity, plants, animals |
|
|
|
Conditions for life |
1. Abiotic synthesis of organic molecules 2. Formation of polymers 3. Packaging of molecules into protobionts, or simple cells 4. Evolution of heredity mechanisms |
|
|
|
Oxygen revolution- when and why |
2.5 billion year ago, proven by bands of iron oxide rust in sediment. Oxygen believed to have come from photosynthetic bacteria (like cyanobacterium) via oxidation of water to oxygen. Led to aerobic respiration->more energy |
|
|
|
Cambrian Diversification Event |
Begins 542mya, proven by new fossils, .any present day phyla appear in the fossil record, large predators appear. Empty niches filled, resulting in more adaptions and complexity
Theories: -adaptions of predator locomotion, pretty defense, exoskeletons -more atmospheric oxygen- higher metabolic rates -genetic changes, new Gene duplications, more raw material |
|
|
|
Theory of diversification |
New niches/environments drive adaptions and diversification Diversity is reduced by extinction events (change in environmental conditions, organisms cannot adapt, creates empty niches) |
|
|
|
Permian-Triassic extinction event |
-95% marine sp, 70% terrestrial sp. Extinct Disruption of seawater circulation, depletion of O2, high conc. Of CO2, major climatic pattern changes. -end of Paleozoic(542-251mya), beginning of Mesozoic(251-65.5mya) Support for asteroid- Wilkes land crater under ice sheet, Antarctica Support for volcano- large eruption in siberia Maybe one or both Results: increased diversity of reptiles, eliminated dinosaur competition, they proliferated. |
|
|
|
Cretacous Extinction event Plus hypothesis that supports it |
-inland seas regressed, cooling, cyclic extinctions. -extinction of non-avian dinosaurs, marine reptiles, some terrestrial mammals, temperate zone plants, many cephalopods -tropical plants, small animals and freshwater organisms not as affected -modern impact hypothesis (Alvarez, Luis and Walter 1980): asteroids- iridium is rare in earth (common in meteorites), and 20-160X more than normal levels of iridium during the cretaceous-tertiary boundary Sharpton(1993)- Yucatan impact crater in Yucatan peninsula, evidence of tsunami from large boulders from Arkansas Texas found in Cuba.
|
|
|
|
Consequences of extinction events |
-Species do not return -Decrease in diversity -Change in ecological community composition |
|
|
|
Life as fixed vs gradual |
-aristotle, Carl von Linnaeus saw organisms as fixed, created by God, and like a ladder, with humans being closest to God -Anaximander and later paleontologists saw organisms as gradually changing, and originating from animals as they require a lot of care. Support from sediment timleine and dating methods Gradual types: -G.cuvier: fossils are different in layers, catastrophism, extinction and new species -J. Hutton and C. Lyell: gradual change is constant like geology, unifomitarianism |
|
|
|
JB Lamrack |
-Gradual change in life as environment changes -use and disuse, unused parts weaken, used parts strengthen and are passed on to next gen. -inheritance of acquired characteristics-can pass modifications of use/disuse to offspring, organisms become more complex |
|
|
|
C Darwin, A Wallace |
Gradual change over time through Natural selection: some traits enhance survival, are passed on to next gen at higher rates. Acts on phenotype (Gene must already be expressed in nature for it to be selected for). Genotypes change through mutation Adaption: to environment
Both called 'decent with modification'
Supported by fossil record, geographic distribution of species, comparative anatomy and genetics |
|
|
|
Micro vs macro evolution |
Micro: short term evolution, within a single population, small scale, variation in genetic traits (alleles) through cross-overs, mutations, DNA deletions or insertions
Macroevolution: long-term evolution, transcends the boundaries of a single species, cannot be readily observed/defined.
Both rely on mutation, migration, natural selection, genetic drift, environmental change Over time, micro develops into macro |
|
|
|
Gene and allele |
Gene: spot on chromosome that codes for an allele Allele: physically expressed trait, varied withing a species. Homozygous- two alleles for the same trait (XX dominant xx recessive), heterzygous- two different alleles for the same trait (Xx, one recessive one dominant). May be more than two alleles. |
|
|
|
Gene pool |
Aggregate of all copies of every type of allele at l loci in every individual in a population |
|
|
|
Gene flow |
The transfer of alleles from one population to another (movement of fertile gametes) |
|
|
|
Hardy-Weinberg principle |
Hardy-Weinberg principle: allele frequency/proportions of traits follows patterns of distribution Frequency of alleles and genotypes in a population will remain constant from F1 to F2 provided that only Mendels segragation and recombination are at work.A null hypothesis defining a population that is not evolving. fr(AA) + fr (As) + fr (AA) =1p^2 + 2pq + q^2=1Equation will stop accurately predicting populations during evolution : mutation, natural selection, genetic drift, and Gene flow alter allele frequency. |
|
|
|
Genetic drift |
Chance events like natural disasters and illnessess (especially in small populations) that cause Gene/allele frequencies to change unpredictably -> founder effect, population bottleneck, reduction in variability Bottleneck: population is dramatically reduced, and the genes of those remain become the only Gene variability in the population Founder : a small portion of a population migrates, and their genes make up the variability of the new population |
|
|
|
Modes of natural selection |
Directional selection: shifts the mean phenotype toward the end of the distribution favoured by natural selection, an extreme
Stabilizing selection: the mean is favoured over extreme phenotypes, favours intermediate phenotypes
Disruptive selection: decrease in distribution at mean, increase of distribution and extremes. Can result in speciation |
|
|
|
Levels of biodiversity |
-Within a group of organisms (Gene pool, populations) -between groups of organisms (Gene flow) -between ecosystems, variety of organisms present in a given ecosystem |
|
|
|
Biological species concept |
Species defined as a group of populations that can interbreed and produce viable fertile offspring (reproductive isolation). Includes separateness, interrupted Gene flow, and a Gene pool of a species.
Pro- accounts for Gene flow, reproductive isolation, model of speciation Con- cannot be applied to asexual organisms or fossils |
|
|
|
Ecological species concept |
Species defined as those that have the same ecological niche Pro-accomodates asexual organisms. Emphasis on disruptive selection/ natural selection Cons- not applicable to fossils |
|
|
|
Morphological species concept |
Species defined as those that share the same unique morphology
Pro- applicable to asexual organisms and fossils, does not need information of general flow therefore can classify dead organisms
Con- relies on subjective criteria |
|
|
|
Phylogenetic species concept |
A species defined as the smallest group of individuals on a.phylogenetic tree Pro-can use morphology and molecular data Con-need to know common ancestor, and what degree of difference makes a species? |
|
|
|
Allopatric speciation |
Speciation due to geographic separation of a population |
|
|
|
Sympatric speciation |
A subset population forms a new species without geographic separation |
|
|
|
Polyploidy |
-Due to a failure in cell division May result in organisms not being able to reproduce. "Microallopatric" -when two different species of different ploidy interbreed, it results in offspring hybrids with different ploidy than the parents, which are usually infertile. It may later change into a fertile polyploid offspring. |
|
|
|
Peripatric speciation |
Small population, founder effect forms new species |
|
|
|
Parapatric speciation |
Part of the population enters an adjacent niche, and forms a new species while in contact with the parent species |
|
|
|
Prezygotic reproductive barrier |
Inhibits mating between species or hinders fertilization of ova should there be mating
Includes: Habitat isolation, temporal isolation (time of day they are active), behavioural isolation (do not understand each other's mating rituals), mechanical isolations (physical and anatomical differences), gametic isolation (gametes do not find each other) |
|
|
|
Postzygotic reproductive barrier |
After egg is fertilized, the zygote is prevented from reaching maturity (more rare)
Includes: reduced hybrid viability (adults are hybrid, sickly and due before maturation), reduced hybrid fertility (#chromosomes, ploidy don't match. Sterile adults), hybrid breakdown (f2 hybrid gen less viable/fit than wither parents) |
|
|
|
Hybridization and hybrid zones |
Result of incomplete reproductive barriers, results in mixed offspring, species have hybrid zones:
-intraspecific, between subspecies of different populations within a species -interspecific, between species
Rarer in animals, more common in plants Shows the limitations of species concepts |
|
|
|
Min requirements for life |
-Membrane to separate internal and external environment -molecules that change energy (ie inorganic to organic molecules as well) -self replicating molecules |
|
|
|
Prokaryotes morphology |
Bacilli-rod Cocci-sphere Spiral Small, 200nm-micrometers Rely on diffusion for metabolic needs May contain capsule, cell wall (+/-) will peptidoglycan, ribosomes, simple internal body plan, inner infolded membrane. Movement: rotational flagellum that is attached to the inside of the cell via axial filament, cillia, gliding motion through secreted slime,
|
|
|
|
Obligate vs facultative anaerobe |
Obligate is poisoned by O2, and use fermentation or anaerobic respiration. Facultative can switch their metabolism depending on presence/absence of O2. |
|
|
|
Nitrogen fixation |
Done only by prokaryotes. Uses enzymes via heterocyst (chemoautotrophs!) Convert atmospheric nitrogen to ammonia |
|
|
|
Reproduction in prokaryotes Plus horizontal Gene transfer |
Asexual: binary fission (cloning) where chromosomes are replicated at the "origin of replication", and two daughter chromosomes move apart, and the cell divides into two. Exponential growth, population can double every 20 min
Sexual: genetic recombination through: -conjugation (dna transfer through sex pili between cells) -transformation (dna taken up from environment) -transduction (bacteriophage/virus transfers dna into and between cells)
The sexual processes are all horizontal Gene transfer, as they can transfer between species and domains (archae and bacteria can transfer dna!). Sexual recombination occurs when conditions favor an adaptive change. Triggers diversification. Takes the shape of plasmids, infections, fusion of organisms. |
|
|
|
Biofilms |
Metabolic cooperation between different prokaryotic species, where genetic material and nutrients are shared. Develop via: 1. Attachment to surface 2. Irreversible attachment 3-4. Maturation, cells grow and divides, change in physiology due to cooperation, matrix develops 5. Dispersion |
|
|
|
Archaea morphology plus classifications based on environment |
Bacilli, cocci, spiral, small. Similar to bacteria but no peptidoglycan. Instead, membrane of branched lipid hydrocarbon (some monolayer, some bilayer) monolayer more stable and can survive more extreme environments
Extreme halophile- lives in salty environments like dead sea, salt cavern (not ocean!) Chemoheterotroph
Extreme thermophile- lives in above 100 degree temps. Chemoautotroph. Some strict anaerobes, metabolize sulfur.
Merhanogens- moderate environment, release methane from water and co2. Chemoautotroph. |
|
|
|
Nutritional modes of archea |
Phototrophs- (ie same as photoheterotroph) use light as every, organic compounds as carbon
Lithotrophs- (ie same as photoautotroph) use inorganic compounds for energy and carbon. Carbon fixation.
Organotrophs- (ie same as chemogeterotroph) use organic molecules and energy and carbon source |
|
|
|
Modes of nutrition in all but Archaea. |
Energy source- Photo vs chemo: light or chemicals Organic/inorganic molecules?- heterotroph (organic) vs autotroph (inorganic)
Photoheterotroph- light as energy source, organic source of carbon. Usually in aquatic or salt loving prokaryotes
Chemogeterotrophic- organic compounds as energy and carbon source. Many prokaryotes, fungi, animals, some plants, Clostridium
Photoautotroph- light as energy source, CO2/other inorganic molecule as carbon source. Cyanobacterium, plants, algae, some protists
Chemoautotroph- inorganic chemicals as source of energy, inorganic source of carbon
Note: chemoh- organic source, chemoa-inorganic source of energy |
|
|
|
Bacteria cell wall (+/-) |
+: thick peptidoglycan layer, with cell membrane underneath. Stains purple in gram stain. -:thin layer of peptidoglycan between cell membrane and outer membrane (made of lipoprotein), stains pink in gram stain |
|
|
|
Bacteria phyla: Proteobacteria |
Subgroup alpha Proteobacteria: nitrogen fixation, symbiotic relationship between legumes. Origination of mitochondria. Subgroup epsilon Proteobacteria: many pathogenic strains |
|
|
|
Other bacteria phyla |
Spirochetes; helical, free living in mud, rotation of internal flagellum filaments. Cause Lyme disease from ticks, flu like symptoms
Cyanobacteria:photoautotroph, chlorophyll a, photosynthetic thylakoids, colonial, spores, live everywhere, stromalolites, fix nitrogen via heterocycts with absence of oxygen.
Gram positive bacteria: diverse. -Firmicutes: strong cell wall, cocci/bacilli, low CG bases -Actinobacteria: soil bacteria, decomposes cellulose and chitin, high CB bases. -mycoplasmas: tiniest cells, no shape, lack cell walls |
|
|
|
Comparison chart between domains |
|
|
