Flashcards
Unit 4
Cards in this deck (114)
- 1EvolutionChange heritable characteristics over successive generations
- 2Malthusian Population Growth-1800
-More offspring produced than environment can support
-Not all organisms will survive to pass on their genes
- Competition for resources & survival - 3Evolution by natural selectionEnvironment “selects” most adapted traits from those existing in population
- 4Lamarck's TheoryTraits change by individual use
- 5Darwin's theoryEnvironment selects traits that are favorable
- 6Letter from Alfred Wallace-Mid 1850s, Alfred Wallace sent Darwin a letter
– Letter described Wallace’s fieldwork in Indonesia
-Wallace proposed an explanation for evolution - 7Evidence for Evolution: BiogeographyStudy of distribution of species through space & time
• Explains how fossils of terrestrial species can be
discovered in areas currently separated by large distances - 8Evidence for Evolution:Comparative AnatomyComparison of body structures between species
• Homologous structures vs analogous structures - 9Evidence for Evolution:Vestigial Structures“Leftover” structures, little or no use to organism
• Had importance in ancestral organism - 10Hardy-Weinberg Equilibriumfrequencies of alleles in non-evolving population remain constant from generation to generation
- 11Conditions for Hardy-Weinberg Equilibrium 5 things that are happening in a population that keep allele frequency in equilibrium1. No mutations in the population
2. Random mating within the population
3. No natural selection (all phenotypes are equally likely to leave offspring)
4. No genetic drift (chance event affecting population)
5. No gene flow (migration in/out)
• Evolution can occur if any of these conditions are not met “Real Life” - 12Mechanism of Evolution:Mutations (create variation)Random mutation: Any gene, good/bad adaptation
• Creates new alleles (shifts allele freq)
• Possibly new phenotypes
• Favorable adaptations accumulate (natural selection) - 13Founder EffectA new population is created with allele frequencies that are different than original population
- 14BottleneckAn event reduces population size; survivors have different allele frequencies than original population
- 15Mechanism of Evolution: Genetic driftChange in allele frequencies due to chance event
• Can be more severe in small populations - 16Mechanism of Evolution: Gene flowNew alleles introduced into population by migration
- 17PrimordialAt or from the beginning
- 18Origin of life?Early 1800s: Flies arise from rotting meat
• Spontaneous generation: Life regularly arises from non-living material (disproved) - 19BiogenesisLife arises from pre-existing life
- 20Abiotic (non-living) synthesis of monomersTested possibility of organic molecule formation
– Amino acids, nucleotides,ATP
• Detected 5 different kinds of amino acids after just 1Week! - 21Abiotic synthesis of polymersPolymerization: Building connected chains of monomers
• Water in droplets evaporate when hot
• Monomers form polymers as water evaporates - 22Packaging of polymers into pre-cellsAmphipathic lipids self-assemble into spheres
– Hydrophobic & hydrophilic interactions
• Polymers can be captured inside
• Inside environment different than outside environment - 23Mass extinctions & Explosive DiversificationsEach killed > 50% extant species
• Eliminate competition, survivors fill gaps in environment, adapt to new resource
availability, new Environment - 24Death of the Dinosaurs (65 mya)1980: Iridium layer in rocks, air full of iridium dust 65 mya
– Iridium rare on Earth, common in meteors
Chicxulub crater, 180km (112 miles) wide, right timeframe - 25Consequences of 10k (~6 mile) Meteor ImpactReleased 1000x more energy than all nuclear weapons
– Several days of intense heat
– Killed dinosaurs & other land animals
– Aquatic & water-associated (crocodiles) animals survive
• Cloud of particles in sky blocked out sun
• Many species went extinct (not just dinosaurs)
– Including ~90% of mammals! - 26Rise of Mammals180 mya mammals appear in fossil record (small, nocturnal)
• Some mammals survive meteor impact
– Underground burrows: Heat protection during impact
– Food: Carcasses & insects until photosynthesis resumes
• 65 mya: # of mammal species increased dramatically
• Predator removed: Daylight adapted, bigger, ...predators - 27Holocene Extinction: “6th Extinction”Ongoing extinction event
• Extinction rate 100-1000X normal level
• Plants, mammals, birds, amphibians, reptiles, arthropods
• Global Super-predator
• Degradation of biodiversity hotspots (coral reefs, rainforests)
• Climate Change - 28SpeciesDifferent kind of organism Biological species concept: Group of populations whose members can interbreed to produce fertile offspring
- 29Morphological species conceptMeasurable features: Structural similarities, DNA similarities
- 30SpeciationEvolutionary process by which new species arise
- 31Biological species conceptGroup of populations whose members can interbreed to produce fertile offspring
- 32Mechanisms of SpeciationIsolation of gene pool from earlier species
- 33Allopatric speciationGeographic barrier
-Emergence of mountain range
• Lake shrinking to several smaller lakes - 34Sympatric speciationNO geographic barrier
-Accident during meiosis produces gametes with extra sets of chromosomes (polyploid)
• To be new species, must produce viable gametes Patterns of Speciation Pace - 35Punctuated EquilibriaLong periods of little change interrupted by brief periods of rapid change
– Hard to detect in fossil record; few transitional fossils - 36GradualismDifferences accumulate slowly over time
– Hard to define boundaries separating species - 37Reproductive BarriersPrevent interbreeding of closely related species
• Prezygotic: Before zygotes
• Postzygotic: After zygotes - 38Postzygotic BarriersSuccessful mating, produces hybrid zygotes
• Death before reproductive maturity
• Sterile (or reduced fertility) hybrids - 39TaxonomyBranch of systematics
– Identification, classifying species
• Assigning scientific names
– Human: Homo sapiens, “wise man”
– Binomial (Genus + species) - 40SystematicsClassifying Organisms
- 41HomologyHomologous: Similar due to shared evolutionary history
- 42AnalogyAnalogous: Same function, different evolutionary path
- 43Convergent EvolutionSame endpoint, different source
- 44Climate ChangeShift in global / regional climate patterns
- 45Global warminggradual increase in global temperature
- 46Consequences of Global WarmingLonger heat waves, droughts, fires, extreme
weather events, ecological refugees, reduced crop yields, flooding
Temp increase: 0.8C (1.4F) since 1880s
Sea level: Currently 1.5 feet (will rise 6-8 ft with 2C increase) - 47Deuterium(stable H isotope) used to calculate temp
- 48Heavy Waterprecipitates sooner than normal water
– Colder air holds less water than warmer air - 49What has caused changes to the earth's climate in the pastAtmospheric composition: Conc. of substances in the air
• Milankovitch cycles: Changes in the earth’s orbit around the sun (hotter or colder)
• Tectonic plate movement: Change in location & amount of surface-exposed land, affecting wind & ocean currents
• Variation in solar output: Energy emitted by sun
• Meteorite impact: Dust blocks out sun
• Volcanic eruptions: Chemical release, dust blockage - 50Plate Tectonics: Continental MovementGrinding: Earthquakes
• Collisions: Mountains (affect regional climate) & volcanoes - 51Natural sources of CO2-Volcanic eruptions
-ocean gas exchange - 52Carbon Isotopes & Atmospheric CO2Source of CO2 can be assessed by measuring isotopes
- 53CO2 increase due to human acitvityVolcanoes: 3% CO2, Humans: 97%
• Deforestation: Burning cleared material
– Produces ~9% of the increase in CO2
• Burning Fossil Fuels: To produce energy
– 87% human-caused CO2 increase: Fossil fuel combustion - 54TissuesCells Acting Together
• Most animal cells are grouped into tissues
– Similar cells that perform specific specialized actions
• 4 main categories of tissue - 55Epithelial Tissue (Epithelium)Covers body surface (epidermis), lines organs
• Cells tightly linked together in a sheet
• Continuously renewed (mitosis)
– Epidermis renewed every 2 weeks
– Cancer risk due to possibility of mutation, combined with UV light or smoke in lungs - 56Connective TissueSparse cells scattered through extracellular matrix
– Extracellular matrix: Molecules secreted by cells for structural and biochemical support
• Function: Bind and support other tissues
– Dermis, links epidermis to blood vessels - 57Loose connective TissueHolds organs in place
• Collagen fibers: ~1/3 of total body protein, most abundant protein in mammals; decreases with age - 58Fibrous connective tissueDense matrix of collagen
• Tendons: Join muscles to bone
• Ligaments: Join bones together - 59CartilageStrong but flexible connective tissue
• Boneless skeleton (outer ear)
• Shock-absorbing pads at ends of bones - 60BoneCollagen hardened by calcium salts
– 99% of calcium in body is in bone (1% is in blood)
• Hard but not brittle
– Osteoporosis: Low calcium - 61Adipose TissueStores fat, stockpiles energy
• Pads & insulates body
• Increase in body fat: Increase in fat molecules stored in cells, not creation of new cells - 62BloodRed & white blood cells (RBCs & WBCs) suspended in plasma liquid
– Transport substances throughout body
• Immune cells
– Fight off infections - 63Muscle TissueMost abundant tissue in most animals
• “Meat” is muscle tissue
• Bundles of long, thin cells called muscle fibers - 64Muscle fibers contract for motionFibers in muscle cells contract to shorten muscles
• Contracts when stimulated by a nerve
• Rigor mortis - 65MuscleSkeletal: Attached to bones by tendons
– Gaining muscle: Bigger cells
– Voluntary movement
• Smooth: Lines organs (intestines)
– Flushing: Blood vessels dilate in response to heat
– Involuntary
• Cardiac: Heart
– Coordinated contraction
– Involuntary - 66Nervous TissueNeuron: Cell of nervous tissue
– Transmits signals to coordinate body activities
• Central Nervous System (CNS)
– Brain & spinal cord
• Peripheral Nervous System (PNS)
– Link CNS to rest of body - 67OrgansTwo or more tissues packaged into one working unit
– Heart, brain, intestines - 68Organ SystemsOrgans working together to provide vital body functions
- 69Nervous SystemMain control system
-Coordinated CNS & PNS neurons - 70Lymphatic (Immune) SystemVessels return fluid from tissues to blood
-Contains cells that protect body from infection - 71Skeletal SystemStrong, flexible structure of bones & connective tissue
-Provides support & protection - 72Integumentary SystemSkin, nails & hair
-Protects against abrasion & water loss - 73Muscular SystemMuscle tissues that produce movement by contraction
- 74circulatory systemHeart & blood vessels
-Carries nutrients & oxygen, removes wastes - 75Excretory (urinary)systemDisposes of waste by creation and elimination of urine
- 76Reproductive SystemMale & female parts, produce sperm or eggs;
-Bring gametes together - 77Respiratory SystemAllows gas exchange (oxygen into blood, carbon dioxide out)
- 78Homeostasis (steady state)Tendency to maintain stable conditions internally, though external environment can change
• Dynamic: Fluctuations due to internal & external cues
• Body temperature stable despite outside temp changes - 79Positive + Negative FeedbackNegative feedback loop:
– Outcome inhibits initiation
– Body temperature regulation
• Positive feedback loop:
– Outcome stimulates initiation
– Less common
– Childbirth: Muscle contraction stimulates release of more chemicals causing contraction
– Cancer mutations: More defects allow more defects
– Global warming - 80ThermoregulationMaintain appropriate body temperature
- 81EctothermsBody heat from environment (sunlight)
– Reptiles, fish, insects - 82EndothermsBody heat from metabolism (body heat)
– Birds & mammals
– Blood vessels constrict to conserve heat, dilate to release
– Shiver to produce heat, sweat to release heat - 83FeverAbnormally high internal temperature
• Brain raises internal temperature in response to detection of invading microbe
• 38-39C (100-102F): Slows bacterial growth, speeds your immune system
• >40C (104F): Damage own body; seek medical help - 84FoodLarge, complex molecules; not in form bodies can use
• Need to break down food: Digestion
• Digestive system - 85Four stages of food processingIngestion: Eating
• Digestion: Breakdown of food into smaller molecules
– Break molecules into small enough sizes to enter cells
– Break into pieces that can be used to build other molecules
• Absorption: Uptake of small molecules into your cells
• Elimination: Disposal of undigested materials - 86Digestive systemAlimentary canal + accessory organs
- 87Alimentary canal“Gut” or digestive tract
– 9m (30ft long), folded to fit - 88Digestive OrgansMouth, pharynx, esophagus, stomach, small intestine, large intestine, & anus
• Accessory organs
– Secrete digestive chemicals into alimentary canal
– Salivary glands, gallbladder, & liver - 89Mouth (Oral Cavity)Site of ingestion
• Teeth: Mechanical digestion (chew, grind, smash)
• Tongue: Muscle, shapes & moves food for swallowing
• Salivary glands: Secrete saliva (liquid +digestive enzymes) - 90PharynxIntersection of breathing and swallowing pathways
– Open to esophagus, trachea, and nasal cavity
– When you swallow, trachea entrance (epiglottis) closes so food goes into esophagus - 91EsophogusMuscular tube that connects pharynx to stomach
• Moves food by peristalsis
– Alternative waves of contraction & relaxation
• Allows food to move toward stomach even when head is lower than chest - 92StomachSecretes gastric juice: Acids, digestive enzymes, mucus
• Churns food and gastric juices into chyme
• Empties slowly (2-6h) into small intestine
• “Growling:” Contraction of muscles of an empty stomach - 93MucusProtects stomach tissue from gastric acids
- 94Stomach UlcersAcid burns stomach lining, worsened by infection
- 95Small Intestine6m (20ft) of alimentary canal; 2.5cm (1in) wide
• Major organ for digestion & absorption
• Food entering small intestine resembles thick soup
-specialized for absorption - 96Large Intestinelong tube-like organ connected to small intestine at one end & the anus at the other.
-four parts: cecum, colon, rectum, anal canal
-Partly digested food moves through the cecum into the colon, water & some nutrients & electrolytes are removed - 97Human NutritionCells extract energy from food by cellular respiration
- 98CaloriesMeasure of the energy stored in food (kcal)
• 60% calories eaten lost as heat (our bodies are warm) - 99Metabolic RateSpeed of energy consumption by body
- 100Basal Metabolic Rate (BMR)Amount of energy to perform basic function
(females 1300-1500 kcal; males: 1600-1800 kcal)
– Activity speeds up metabolic rate - 101Eating DisordersAnorexia nervosa: Self-starvation, fear of weight gain
– Bulimia: Binge-eating followed by induced vomiting, laxative abuse
• Obesity: Over-nourishment, high body mass index (BMI) - 102Structure & Function of Respiratory SystemDiaphragm attached to lungs,controls breathing
– Negative pressure
– Impact stuns diaphragm,“knocked the wind out”
• Air enters, passes pharynx,enters larynx (voice box),trachea (windpipe)
• Trachea forks into bronchi, 1leading to each lung
• Branch to bronchioles, end in alveoli (gas exchange) - 103Vertebrates (humans)Closed circulatory system
– Cardiovascular system: Pump, closed tubes, & fluid - 104Pulmonary circuitBetween heart & lungs
- 105Systemic circuitBetween heart & rest of body
- 106The HeartMuscular organ, fist-sized, 4 chambers (2 atria, 2 ventricles)
• Atria receive blood, ventricles pump it out; valves prevent backflow
– Right ventricle pumps blood to lungs
– Left ventricle pumps blood to body - 107Cardiac CycleCardiac cycle (one heartbeat, ~0.8 seconds): Blood moves
through pulmonary & systemic circuits simultaneously - 108Heart RateHealthy resting heart rate 70-80 beats / minute
• Rate regulated by pacemaker cells
– Cells in right atrium, generate electrical signals to coordinate heart muscle
– Signal moves from pacemaker to AV relay point, delaying signal 0.1s
(Atria contract 0.1s before ventricles) - 109ArteriesCarry blood away from heart
- relax between contractions (diastolic) - 110Veinsreturn blood to the heart
- 111CapillariesNutrient exchange between bloodstream & cells
- 112PulseElastic stretching of arteries as blood is forced to move forward by heart (systolic)
- 113Blood pressureForce blood exerts against vessel walls
• 120/80 “120 over 80” - 114Capillaries & Blood FlowOnly 5-10% of capillaries have steady blood flow (vital organs: brain, heart, kidneys, liver)
• Muscles control which are open; blood flow as needed
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- Biology Flashcards on Unit 4 , created by Monica Vatamaniuc on 22/07/2022.
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