Exam 1 Study Guide
Exam 1 Study Guide Bio 112
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This 7 page Study Guide was uploaded by Sophie Kreutz on Monday March 14, 2016. The Study Guide belongs to Bio 112 at College of Charleston taught by Bidwell in Fall 2016. Since its upload, it has received 21 views. For similar materials see Evol, Form, and Func of Organisms in Biology at College of Charleston.
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Clutch. So clutch. Thank you sooo much Sophie!!! Thanks so much for your help! Needed it bad lol
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Date Created: 03/14/16
Bio Study guide Exam 1 Natural Selection: - 30-50 million species and we've only identiﬁed 2 million - 99.9% of life is extinct - Earth is 4.6 bill years old, life has been here for 3.8 bill Evolution- descent with modiﬁcation Order —> family —> genus —> species Evolution occurs through: - natural selection - genetic drift - gene ﬂow - mutation Natural Selection: unequal reproductive success (non random) - survival of the ﬁttest 1) individuals vary 2) variation is heritable 3) organisms produce more organisms than will survive 4) better adapted individuals will have more offspring Adaption - a trait that increases an individuals “ﬁtness” - comes from random changes (mutations) - most mutations are not adaptations because they are negative Evolutionary ﬁtness - contribution of an individual to the next generation Darwin and Wallace - published in 1859 Types: Directional selection: adaptions ﬂuctuate due to environmental conditions (beaks or mice fur on a beach) - removal or increase in pressure for a speciﬁc trait Diversifying selection: selecting against the average phenotype (two extremes, either pale or dark fur, no brown) Stabilizing Selection: extreme phenotypes to attract mates - ornamentation occurs in populations with adequate food and mate choice - intrAsexual is where two animals of the same gender compete for attention - Weaponry develops when males defend prime Realestate for mating Sexual dimorphism: extreme differences in phenotype of two genders other than their sexuality **removing pressure of selection allows the species to ‘grey’ out and return to normal conditions Genetic Drift: random exchange, exaggerated in small populations - population is removed by pure chance - can occur with lava or mud ﬂows 1) Bottleneck effect: a catastrophe causes a population to decrease in size drastically that also decreases genetic diversity (makes animals like cheetahs all practically clones because there is no diversity) 2) Founder effect: a few individuals from one population start a new population with a different allele frequency (lion ﬁsh) Gene Flow: movement of alleles between two populations by immigration/emigration - the more gene ﬂow between two populations, the more similar they are - decreasing gene ﬂow decreases similarity and increases difference Mutation: permanent changes in DNA that increase variation to set up natural selection ** individuals do not evolve, only a population does and it can happen within one generation **evolution is not random, but mutation and genetic drift are Evidence for evolution: 1) observation 2) fossil record 3) biogeography (geographic distribution of species) 4) Comparative anatomy (anatomic homologies indicate evolution from a common ancestor) Homologous species: evolved from a common ancestor but not have different functions - built the same way because of evolutionary past - Homologous plants: venus ﬂy trap (leaves turned to jaws), poinsettia (leaves turned colors to resemble ﬂowers), cactus (leaves turned to pines) Analogous species: look the same due to function but have no evolutionary history - no common ancestors but common selective pressures - evolved through convergent evolution - arrived at the same conclusion independently) Rudimentary structures: leftover from evolution - humans can wiggle ears, tailbone, goosebumps, wisdom teeth - modern whales have pelvic bones from when they once walked on land 5) Comparative embryology 6) conserved molecular characters - compare DNA RNA proteins and enzymes Theories: descriptive, exploratory, explanatory and predictive - they explain broad phenomenons in nature Laws: describe procedures in nature mathematically Neutral Variation - not every trait is being selected for, some are just along for the ride (ﬁngerprints) - trade offs exist in populations Modern synthesis: combine ﬁeld of population genetics with darwin’s theory of evolution by natural selection To stop evolution: (HW eq) - no mutation, random mating, no gene ﬂow (isolation), large population size (no drift), no selection (equal reproductive success) Genotypic frequency: p*2+2pq+q*2=1 Allele frequency: p+q=1 - sexual reproduction alone does not cause natural selection, it just shufﬂes the deck but doesn't change the frequency - inbreeding reduces heterozugous and increases homozygous genotypes - homozygous recessive are more prone to disease and disorders Species: one or more population of organisms with the potential to interbreed with one another but not with members of other such groups Prezygotic barriers: stop sperm from meeting egg - behavioral isolation (usually mating) - mechanical isolation (chiwawa and great dane) Postzygotic: stop offspring from forming, surviving and breeding after fertilization - hybrid inviability: zygote dies before it develops - hybrid sterility: the hybrid may be born, but can not breed (liger) the chromosomes don’t pass mitosis - hybrid breakdown - the offspring are weak and subsequent generations ave many defects - natural selection does the rest - within a species; variety (used with plant) and breed (used with animal) - for a new species to form, you need genetic isolation and divergence Allopatric speciation: geographic isolation where populations are physically separated - is dependent on how mobile the species is, are its seeds carried? ﬂies?) - highways, mountains, tectonic movement - youngest islands have the least diversity - Ring species: a species splits (say around a mountain) and comes back together but are incompatible by the end Sympatric Speciation: semi random, diversifying selection (ﬁnches) where a different characteristic will start small and develop to be very different. - a random change can change feeding and mating which isolates the species greatly - happens by genetic errors like autopolyplaudy where the whole set of chromosomes duplicate rather than split in anaphase PLANT STRUCTURE - all started with green algae, small water born plants (resembled mosses) (sperm swim to egg) 1) nonvascular plants - no vesicles to move things around within them 2) Vascular plants 1) Ferns and seedless vascular plants 2) gymnosperms - conifers and pines (pollen and a naked seed) 3) Angiosperm - ﬂowering plants (ﬂowers and fruits) Pollen - sperm that can be moved through the air Seeds - protect the food for the embryo and have the ability to wait (suspended animation) - ﬂowers help because now that can use pollinators and expend less energy making seeds - Fruits form from ﬂowers an have seeds (designated for transportation) PLANT BODIES: Organs: roots, shoots, leaves, reproductive structure (ﬂower) Tissue: ground - photosynthetic cells and ﬁller cells vascular - xylem and phloem for transport and support Dermal - outermost layer for protection and to prevent from drying - all are connected and continuous within the plant body Cells: - communicate through the plasmodesmata - use cellulose for structure - roots do not have chloroplasts TYPES OF ANGIOSPERM: EUDICOTS: maple trees, peonies, - two cotyledons (parts of embryo) - tap roots - 4-5 ﬂoral parts - net like leaf veins - vascular bundles in a ring - three pores on pollen grain MONOCOTS: grass, lilies, palm trees, orchids - one embryonic leaf - ﬁber-y roots - parallel array of veins - one pore furrow - even dispersal of vascular bundles GYMNOSPERM: - needles instead of leaves, pine nuts, pine trees Roots: anchor and absorb water and nutrients - conduct the water and nutrients to shoots and for storage (starch) Modiﬁed roots: strictly for storage (yams and sweet potatoes) Adventitious roots: prop roots - mangroves Aerial roots - hang, curtain ﬁg tree Pneumatophores - snorkle roots Shoot systems: stems (internode) - support, photosynthesis, transport, storage, reproduction (most plants are hermaphrodites) Terminal bud: at the tip of growing stem or branch Axillary bud: armpit of the plant (in a node) Lateral buds: can turn in to stems Modiﬁed shoots: Stolons: horizontal roots of strawberries Rhizomes: horizontal stem underground (iris) Tubers: potatoes! modiﬁed to store starch * in cacti, the leafs are actually stems and the spikes are leafs LEAF ANATOMY: Dermal: Cuticle - wax, hydrophobic Epidermis layer - has parenchyma cells and guard cells Periderm - cork cells and corn cambium (bark) Trichomes - hairs (poke through cuticle) can trap water, be sticky, poisonous Stoma - guard cells surround this pore (gas exchange) (O2 and H2O out and CO2 in) Vascular : Xylem - transports water and nutrients one way (roots —> shoots and out stomata) - tracheids in all vascular plants )jagged horizontal movement of water which wastes time and since angiosperms have tubes, it is more efﬁcient) - dead at maturity - vessels and ﬁbers* are unique to angiosperm *(that make hemp thread-like) - regulated by stomata - PASSIVE Phloem - transports sugars two ways wherever needed for metabolism and storage - all vascular plants have sieve plates (with big pores for food transport and connect phloem) sieve tube members and companion cells (last two only in angiosperm) - phloem are food conducting, alive at maturity and have cytoplasm (not organelles) - ﬁbers are only in angiosperm - pressure ﬂow is ACTIVE and passive - need the xylem - source —> sink Veins are made of these ^ * ﬁbers distinguish hard vs softwood (?)palisade: photosynthesis (?)Spongey: gas exchange area in spaces Ground: Parenchyma - AP cells - in leaves they are photosynthetic - can differentiate into other cell types if needed Collenchyma - ﬂexible support (like the strings in celery) Sclerenchyma - hard woody and gritty for protection (pears) (two cell walls) Pedeol: base of each leaf - a leaf is determined by weather its pedeollll has an axillary bud at the base Leaves: alternating spiral, opposite, whirls, basal rosette, simple, pinnately compound, palmately compound, doubly compound Modiﬁed leaves: tendrils: climb like a cucumber spines: cacti, shoo away predators bright colored leaves, poinsettia Succulent and bulbs (onion or pitcher plant) XYLEM AND PHLOEM Hypertonic: water moves out of the cell because solute solution is greater outside - cells become plasmolyze) Hypotonic: water moves into cell because solute concentration is greater inside - becomes TURGID (best for plants) Water potential: Y=Yp+Ys - negative is a pulling sucking force - positive is pushing force - always ﬂows from high to low (high to more negative) - roots suck up water because their cells are hypotonic in comparison to the soil - root hairs help collect H2O and increase the surface area - water moves into the plant because the water and the cellulose are both polar (adhesion) - water also sticks to itself creating a chain (cohesion) - a Casperian strip connects the cells and makes an impermeable barrier, forcing the water to ﬂow through the cell and release nutrients Aloplastic: moves through the roots via cell walls Symplastic: moves through the cells themselves Transpiration creates a suction that moves water up through the roots - is stronger the farther up you go Water is moved up the xylem by: - stomata opening during the day to exchange CO2 and the burger pressure and osmosis changes the pore size of the stomata (negative pressure) - factors that regulate the stomata (stimulated by light, K+ ions make a pump, levels of CO2 (if low, they open), water stresses) - Guttation: water is collected so much through the roof that it ﬁlls up the tubes and pushes out the top! (positive pressure) Sugars are moved through the phloem by: - translocation sugars moved through the vascular system and phloem - uses the pressure from the xylem to move sugars down from leaves to roots for storage or shoots (where the ﬂowers are) - the source adds sugars to the phloem (translocation/loading) - water enters the system because it is hypotonic - pressure ﬂows down to low pressure areas and the sink takes sugars from the phloem - the system is so pressurized that it practically squirts out when tapped *ﬂowers can not photosynthesize and need sugars to grow How plants grow: - grow their whole life - Embryonic stem cells are omnipotent and can become any cell the plant needs - plants keep these their whole life where we loose them as babies - through mitosis, the cells split but one stays embryonic - MERISTEMS (can be ground, vascular or dermal) Apical meristem - elongation of roots and shoots, adding length to tip (not extending) - primary growth - root cap protects the meristem from deterioration - secretes mucigel to lubricate the path - determines geotropism - constantly replenished ** growth of cells is actually what moves them through the soil (they ﬁll with water and push) - in the zone of elongation ROOT HAIRS - extension of dermal cells Shoots grow and always leave behind an axillary bud and always have a terminal bud Determinant growth: leaves, ﬂowers, fruits Inteterminant: roots, shoots ** cells can differentiate and de-diferentiate (become embryonic again) Lateral meristem - growth in girth, secondary - Eudicots are the only ones with growth rings and woodenness - in gymnosperms tree layers: cork, cork cambium (periderm), living phloem (bark) vascular cambium, sapwood, heartwood - as the tree expands, it leaves behind the old xylem, made by the vascular cambium, which makes the rings - Lignen turns old xylem into wood - heartwood is only there for support - phloem does not build up, but rather is pushed out by the vascular cambium - we can distinguish growth rings because the cell chape decreases during winter - rings are obvious in temperate trees - knots in the wood where old branches used to be! SG - limits on rate of evolution: selection, variance, heritability - genetic diversity is the raw material that allows NS to work - Biological species concept: Species are groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups - Vestigial structures are often homologous to structures that are functioning normally in other species. Therefore, vestigial structures can be considered evidence for evolution - 1. Plants make their own food - 2. Plants have a cuticle - 3. Plant cells have a cell wall - 4. Plants reproduce with spores and sex cells - - What tissuesarise from primary growth in the shoot? - What tissuesarise from primary growth in the root? - How is K+ involved in opening/closing stomata?
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