Concepts in Biology Final Exam


Flash cards for college level general biology
Flashcards by mlszala, updated more than 1 year ago
Created by mlszala about 10 years ago

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Question Answer
-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 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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