Pregunta | Respuesta |
-Hierarchy of Life | Molecules Organelles Cells Tissues Organs Organisms Populations Communities Ecosystems The Biosphere |
Levels of Organization | Each level represent the UNIT of the next level of organization |
Emergent Properties | Properties that CANNOT be explained by the properties of the lower levels |
The shared characteristics of life | -All living organisms are built of cells -organisms reproduce via the heredity material DNA -All living things grow and develop -living organisms capture energy from the environment -organisms sense and respond to their environment -organisms show high levels of organization -living organisms evolve |
Major life groups | Bacteria Archaea Protists Plants Fungi Animals |
Charles Darwin and the origin | 1.Descent with Modification 2. Natural selection |
Natural Selection | -Variation -Struggle for Existence -Differential Reproduction ADAPTATIONS |
2 Causations | -Proximate causations (functional) -Ultimate causations (evolutionary) |
2 Methods of exploration | -Induction(Discovery Science) -Deduction(Hypthetico-deductive science) |
Griffith Experiment | *Living S Strain- Mouse Dies *Living R stain-Healthy *Heat S Strain- Healthy *R Strain and Heat S Strain-Dies |
Hershey Chase Experiment | 32 P containing DNA and bacteria- blend -> Little 32P in supernatant 35S containing phage coats and bacteria- blend -> Most 35 S in supernatant Conclusion: DNA, not protein enters bacterial cells and directs the assembly of new virus particles. |
Chargaff's Rule | A=T G=C A and G are Purines T and C are Pyrimidines |
Watson and Crick | . |
The double helix Model | -A double stranded helix -Uniform diameter -Two strands run in opposite directions -Base pairing is complementary |
The structure of DNA is essential to | its function: DNA replication |
3 Models for DNA Replication | Semiconservative Conservative Dispersive |
Meselson and Stahl's Experiments | . |
How does genetic information get from the nucleus to the cytoplasm? | Transcription |
How does genetic information is encoded to produce proteins? | Translation |
Central Dogma | DNA<-> RNA -> protein |
Transcription and the messenger hypothesis | DNA-> Transcription(mRNA)->Translation(tRNA)-> protein |
The genetic code | -A three letter word code (codon) -Provides the specificity for protein synthesis -the code is redundant -code is not ambiguous -code is universal |
Chromosome | Physically organized form of DNA in a cell |
Chromatin | complex of DNA and protein |
Sister Chromatids | two identical strands of DNA making up a chromosome (joined at the centromere) |
How many chromosomes do humans have? | 46 chromosomes= 2 sets of 23 (one set from each parent) (Karyotype) |
Homologues | 2 chromosomes composing a pair |
Mitosis | Asexual reproduction |
Meiosis | Sexual reproduction e.g. human gametes n=23 Haploid |
Cell cycle | Mitotic phase:Mitosis and Cytokinesis S phase: DNA synthesis G1(first gap) and G2(second gap) phase: Cell growth |
Mitosis | Interphase Prophase Prometaphase Metaphase Anaphase Telophase |
Interphase | . |
Prophase | . |
Prometaphase | . |
Metphase | . |
Anaphase | . |
Telophase | . |
Interphase: G2 | Formation of 2 centrosomes (microtubule organizing cneter)= area in the cell were microtubules are produced. Within each centrosome-> 2 centrioles made up of microtubules Microtubules grow into a spindle which is responsible for separating replicated chromosomes into the 2 daughter cells |
Meiosis I | separates homologues |
Crossing over | Exchange of DNA |
Meiosis II | Separates chromatids |
Differences between Mitosis and Meosis | -Number of divisions -synapsis of homologous chromosomes -number of daughter cells -genetic composition -role in animal body |
Genetic Variation | -independent assortment -crossing over -random fertilization |
Independent Assortment of chromosomes | contributes to genetic variation due to the random orientation of tetrads at the metaphase plate |
Evolutionary adaptation depends on a populations genetic variation | -darwin recognized the importance of genetic variation in evolution via natural selection. -a population evolve through the differential reproductive success of its variant members -those indv best suited to the local env leave the most offspring, transmitting their genes in the process -this natural selection results in adaptation , the accumulation of favorable genetic variations |
phenotype= | genotype+environment |
How do we account for, and predict patterns of inheritance? | Blending Inheritance Particulate Inheritance |
Mendels Monohybrid crosses | . |
Particulate Inheritance | -the units of inheritance are present in discrete particles -these units occur in pairs ( 2 units for each character) -the units segregate during the formation of gametes -the units retain their integrity |
1.Unit of Inheritance 2. Each unit for a particular gene | 1. Gene 2. Allele |
First law of mendel: Law of segregation | -alternate versions of genes (alleles)= variation in heritable traits -for each character an organism inherits 2 alleles (one from each parent) -the dominant allele determines the organisms appearance -the 2 alleles separate during gamete formation ending up in different gametes |
What happens when parents differ at 2 or more loci? | two possibilities: -traits may be associated -traits may segregate independently |
Mendel's 2nd experiment di hybrid crosees | . |
Mendels law of independent assortment | Alleles of different genes assort independently of one another during gamete formation -meiosis and recombination account for the independent assortment of alleles |
Codominance | The heterozygous individual expresses BOTH phenotypes -ex. ABO blood |
Incomplete Dominance | Both traits show -ex. cross with red flower and white flower =pink flower |
polygenic traits | -continuous variation -quantitative traits -polygenes mediate quantitative inheritance |
Evolution | Change through time lineage of ancestral-decendant populations -> descent with modification |
Types of biological change | 1.developmental change 2. change in the composition of ecosystems 3. change between generations |
Evolution Transformism Creationism | . |
Descent with modification | All organisms related through descent from some unknown ancestor |
Natural Selection | Differential Success in reproduction that leads to adaptation of populations to their environment -primary mechanism of adaptive evolution -accumulates and maintains favorable genotypes in a population -there is variation -traits are inheritable -differences in fitness associated with the traits -more individuals are produced than they are able to survive |
evidence for evolution | 1.on a small scale, evolution can be observed in nature (galapagos finches) 2.Evolution can be produced experimentally (artificial selection) 3.the concept of species and the hierarchal organization(reproductive interbreeding, phenotype sim) 5. homologous sim among living groups(DNA) 6.Fossil Evidence for transformation of species 7. The order of the main groups in the fossil record.(anatomical homologies) |
Genetic variation in natural populations | -gene pool -measuring genetic variation *allele frequencies, genotype frequencies,heterozgosity |
p= | D+1/2H |
q= | R+1/2H |
Hardy Weinberg Non-evolving Population | -random mating -large population size -NO mutation -NO migration -NO selection *allele and genotype frequencies remain constant from generation to generation |
1.Allele Frequencies 2.Genotype Frequencies | 1. p+q=1 2. p^2+2pq+q^2=1 |
Microevolutionary Processes | -mutation -migration -genetic drift -natural selection |
Mutation | -changes in genetic material -ultimate source of genetic variation -mutation rates are low |
Genetic Drift | -Random changes in allele frequencies due to sampling -> a sampling effect *gametes represent a sample of the population -The effects of genetic drift are more drastic in SMALL populations |
Bottleneck Effect | . |
Sexual selection | -natural selection for mating success -can result in sexual dimorphism, marked differences between the sexes in secondary sexual characteristics *Intra sexual selection(between indv) *Inter sexual(ex. showiness of males appearance) |
Maintaining genetic variation | -geographically distinct subpopulation -balancing selection -heterz advantage -frequency dependent selection -neutral mutations -sexual reproduction |
Heterozygote Advantage | resistance to malaria sickle-cell disease |
The biological species concept | a pop or group of pops whose members have the potential to interbreed with one another in nature to produce viable fertile offspring but who cannot produce viable fertile offspring with members of other species |
1. Anagenesis 2.Cladogenesis | 1.phyletic evolution 2.branching evolution |
How do new species arise? | -a barrier is established -populations diverge genetically -reproductive isolation |
Allopatric Speciation | a new species form while geographically isolated from its ancestor |
Sympatric Speciation | A new species arise within the range of the ancestral species. No geographic isolation |
Parapatric Speciation | Reproductive isolation develops between adjacent populations |
Factors influencing speciation rates | -species richness -range of distribution -behavior -env changes -generation times |
phylogenetic trees | -hypotheses about history -a tree is a working hypothesis |
Homology | -a evolutionary term -implies common ancestry -different than similarity |
Primitive Characters | characters common to a taxon more inclusive than the one we are trying to define( shared ancestral characters) |
Derived Characters | A character unique to a particular clade (shared derived characters) |
Homoplasia | Traits that are similar for some reason other than inheritance from a common ancestor-> convergent evo,parallel evo, eve reversals |
convergent evolution | . |
Parallel Evolution | Similar developmental processes may result in parallel evolution of similar traits in distantly related organisms |
Traits used in reconstructing phylogenies | -morphology and development -molecular traits *DNA sequences *protein sequences |
Advantage of molecular data | -DNA and proteins evolve in a much regular manner than morph or pays characters -more amenable to quantitative treatment -molecular data is abundant -universality of DNA or protein information |
Maximum parsimony(cladistic analysis) | The BEST hypothesis is the one that requires the fewest homoplasies |
Neutral mutations vs no neutral mutations synonymous vs non-syn subsititutions | . |
The neutral theory of molecular evolution | most variations are neutral. The rate of fixation of mutations is constant and equal to the mutation rate -> the freq of neutral alleles should change slowly over time. |
Origin of genes | -gene duplications -gene families -functional diversification -pseudogenes |
Genome Organization | -Variation in genome size -number of genes -no-coding regions |
The Earth is very old | -radiometric decay in fossils and rocks -magnetic fields of rocks -relative are of sedimentary rocks -the earth is 4.5 bya |
Changes in the Earth environment | -cooling of the earth -increase in oxygen concentrations -hot/humid and cold/dry cycles -continental drift -extraterrestrial collisions |
Patterns in the fossil record | 1.organisms of particular types are found in rocks of specific ages 2. as we move from ancient periods of geological time toward the present, fossil species increasingly resemble species living today 3. extinction is inevitable fate of all speices |
3 major evolutionary fauna | -cambrian fauna(trilobites, brachiopods) -Paleozoic fauna(sea stars,cephalopods) - Modern fauna(insects, birds) |
Origin of life | -all life is cellular -major atoms: C,H,N,O,P,S -metabolism (biochemical reactions) -DNA, RNA, and proteins -flow of energy(ATP) -genomes are composed of DNA or RNA -reproducing systems give rise to altered phenotypes |
4 Major stages for the origin of life | -abiotic synthesis of small organic molecules -formation of complex molecules(polymers) -the origin of self replicating molecules -the formation of protobionts |
Monomers 1.Amino Acids 2.Nucleotides | Polymers 1.proteins,polypeptides 2.nucleic acids, DNA and RNA |
Origin of protbionts | -Oparins theory of coacervates -formation of lipid bilayer membranes -origin of self replicating molecules -formation of protobionts |
Origin of self replicating molecules: RNA | -some RNA have catalytic activity(ribozymes, splicing) -RNA is more stable than DNA -RNA can be used as a template for the synthesis of DNA -Central dogma |
Viruses | Viruses (RNA and protein) are not "alive" that is they cannot replicate unless they are inside another organism |
Shared characteristics of 3 life domains | -glycolisis -DNA>>Proteins (trans, transl) -universal genetic code -membranes and ribosomes -all require energy |
Each domain has distinct features | -cellular organization -gene organization -translation mechanisms |
1.Photosynthetic aerobes->chloroplasts-> 2.Photobacteria->mitochondria-> 3.Methanogenes, Thremophiles ->ancestral eukaryote -> | 1.Photosynthetic protists->plantae 2+3. Non photosynthetic protists ->fungi, animalia |
Critical role of prokaryotes in the biosphere | -cycling of N,S and C -obtain energy from sun or inorganic sources -symbiotic relations with animals and plants -metabolic diversity |
The prokaryotic cell | -lack nuclei, organelles and cytoskeleton -circular DNA and plasmids -infolding of plasma membrane -division by fission but exchange DNA -loco: Flagella, gas vesicles or gliding -protective cell walls |
Conjugation | -genetic recombination -DNA exchange |
structural and functional adaptations of prokaryotes | -cell wall w peptidogylcan -hair like appendages help cells adhere to surfaces -flagella for movement -formation of endospores(remain viable in harsh conditions!) -circular chromosome -rapid reproduction by binary fission -increased genetic variation allowing adaptive evolution due to rapid repro, mutations, and genetic recombination |
Protobacteria | -largest group of bacteria -high metabolic diversity -five major groups -mitochondrial ancestors |
Cyanobacteria | -important photoautotrophs -single cell and colonial -some form Spores -choloroplast ancestors |
Other types of bacteria | -spirochetes -chlamydias -firmicutes |
Archea unique characteristics | -close evol relationships with eukarya -no peptidogylcan in their cell walls -distinct lipids in their cell membranes -extremophiles and methanogens 2 major groups: crenarchaeota and euryarchaeota |
Threats and utility of prokaryotes | Threats -cause ~50% of human disease -increasing resistance to antibiotics -biological warfare Utility -research tool -nutrient cycling -symbiotic organisms -bioremediation |
Early origin of eukaryotes | -arise 2.1 bya -dependent on water -oxygen key to development -huge diversity of life styles w increasing complexity |
Distinguishing features of eukaryotes | -membrane bound organelles and nucleus -many nutritional modes -wide variety of mechanisms for movement -reproduce asexually and sexually |
Eukaryotic cell (compartmentalized cell) | -flexible surface(loss of cell wall) -cytoskeleton -nuclear envelope -digestive vesicles -presence of organelles |
Protists | -all eukaryotes that are not plants, fungi, or animals -structure: most unicellular -mobility:cilia or flagella, pseudopodia(false feet) -repro:asexual(fission, budding, sporulation), Sexual(mitosis, meiosis and sex),some alt of gen |
Endosymbiosis | A process in which unicellular organisms engulfed other cells that evolved into organelles in the host cell (much of protist diversity resulted from this) |
Plants | photosynthetic eukaryotes, use cholorophylls a and b, store carbohydrates as starch and develop from embryos protected by parental tissue -a monophyletic group -evolved from green algae -fossils -475 mya |
Terrestrial adaptations of plants | -apical meristems -alt of gen -walled spores produced in sporangia -multicellular gametangia -multicellular dependent embryos -acquisition of a cuticle -vascular system -gas exchange and minimize water loss (stomata) |
Bryophytes | -non-vascular plants -dominated by gametophyte stage -sporophyte dependent on gametophyte -moisture needed for reproduction |
vascular plants | -flourished in carboniferous period -fossils date back about 429 mya. -ferns and other seedless vascular plants(non-tracheophytes) formed the first forests |
Main characteristics of modern vascular plants | 1.life cycles w dominant sporophytes 2.transport in xylem and phloem 3.evolution of roots 4.evolution of leaves 5.evolution of sporophylls and spore variation |
Homosporous | one type of spore developing into a bisexual gametophyte( ferns) |
heterosporous | 2 types of spore (all seed plants) -Megaspore(develop into female gametophytes) -Microspore (develop into male gametophytes) |
Evolution of seed plants | -360 mya. -gymnosperms: naked seeds -angiosperms:flowering plants |
Gymnosperms | -naked seeds (cones) -abundant xylem and extensive secondary growth -4 plant phyla: cycadophyta, gingkophyta,gnetophyta,coniferophyta -gamertophye reduced -sporophyte dominant and independent -pollen: eliminated the moisture requirement for fertilization |
Angiosperms | -flowering plants -double fertilization (triploid nutritive tissue and endosperm) -enclosed seed -1 phylum:anthophyta |
Advantages of a seed | -develops from the whole ovule -is a sporophyte embryo(2n) along with its food supply, packaged in protective coat |
Systematics | Fungi and Animalia as sister kingdoms(more closely related to each other than to plants or other eukaryotes) -supported my molecular evidence |
Features of Fungi | -feed by absorption -large surface area and rapid growth -reproduce sexually or asexually from spores -many hace a heterokaryotic stage -5 major phyla:chytrids, zygomycetes,glomeromycetes,ascomycetes, basidiomycetes |
Absorptive Nutrition | -fungi decompose dead organisms, fallen leaves, and other organic materials -ecosystems depend on fungi for nutrient cycling -symbionts -Absorptive Structures: Mycelium, exoenzymes, cell walls made of chitin |
Fungi specialized to grow and spread | -concentrates on adding hypal length and absorptive surface area -hyphae may be coenocytic or separate |
Fungi Nutrition | -heterotrophs that feed by absorption -secrete into their surroundings exoenzymes that break down complex molecules and then absorb the remaining smaller compounds |
Heterokaryotic Stage | -nuclei of hyphae and spores are usually haploid except for transient stage -some mycelia may fuse, allowing for some gene exchange |
Fungi Ecology | -decomposers:absorb nutrients from nonliving material -parasites:absorb nutrients from cells and living hosts -mutualistic symbionts:absorb nutrients from a living host but they also provide a benefit to the host |
What caused diversification? | -oxygen levels -predator prey relationships -variation in development gene expression |
Main characteristics of animals | -multicellular eukaryotes -heterotrophic -bodies held together by structural proteins such as collagen -unique specialized cells (muscle and Nerve) -reproduce sexually (dominant diploid stage) -tissues that develop from embryonic layers -SAME genes expressing different body forms: Homeobox (Hox genes) |
3 major stages in animal development | -fertilization:interaction of sperm and egg -cleavage: repackaging the cytoplasm -Gastrulation:producing the body plan |
Embryonic tissues | Endoderm(digestive tract and derived organs),mesoderm(muscles and organs between digestive system and outer covering),ectoderm( outer covering and CNS) |
4 characteristics that can be used to classify organisms | 1.Symmetry:radial, bilateral 2.Tissues: Diploblastic or triploblastic 3.body cavities:coelomates, pseudocoelomates, or acoelomates 4.cleavage and fate of the blastopore: protosomes or deuterostome |
Annelida | -coelomates -segmented worms(series of fused rings) -complete digestive system -closed muscular circulatory system -ex.earthworms, leeches, marine worm |
Porifera | -sponges -suspension feeders -simple: sac perforated with holes -complex: branches with multiple openings -2 cell layers separated by mesophl -defense:spicules, antibiotics, and other defensive compounds |
Cnidaria | -carnivores that use tentacles to capture prey( cnidocytes) -radically symmetric -mostly marine -sessile(polyp) and floating(medusa) forms -true tissues:gastrovascularcavity and nerve net -sac with central cavity -ex. hydras, jellies, sea anemones and coral animals |
Platyhelminthes | -acoelmates with gastrovascular cavity -flattened body -aquatic and damp habitats -many are parasitic -nervous system more complex and centralized -gastro cavity with only one opening--fine branches digestive system -ex. tapeworms |
Mollusca | 3 classes: Gastropoda(snails and Slugs), Bivalvia (oysters and clams) , Cephalopoda (octo and squids) -muscular foot, visceral mass, and mantle -most are marine -soft bodied animals but many protected by hard shell |
Nematoda | -non-segmented pseudocoelomates covered by a tough cuticle -ex. nematodes or roundworms |
Arthropoda | -segmented coelomates that have an exoskeleton and jointed appendages -hard exoskeleton -jointed appendages -well dev sensory organs, open circa systems, and specialized gas exchange organs -4 subphyla:cheliceriformes (spiders), Myriapoda(millipedes), Crustacea(crabs), hexapods(insects) -some metamorphosis |
General evolutionary trends | -diplo or triploblastic -tissue specialization -segmentation -specialization of appendages -increased complexity of nervous system |
Echinodermata | -ex. sea stars -water vascular system -coelomates -tube feet for movement -prominent in marine env -evolved secondarily from bilateral symmetry of ancestors |
Chordata | -dorsal nerve cord -notocord -pharyngeal gill slits -post-anal tail -segmented musculature |
Chordates | -bilaterians and deutrostomes -radial and indeterminate cleavage |
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