The Physicians Health Study was a randomized, double-blind, placebocontrolled trial designed to determine whether low-dose aspirin (325 mg every other day) decreases cardiovascular mortality. The experiment assigned 11,037 physicians at random to receive aspirin, and 11,034 to receive a placebo. a. The following table shows the incidence of cardiovascular events. Whatwould you conclude about the effects of aspirin? b. The following tables details cardiovascular mortality. What would you conclude about the effects of aspirin?
BIOL 111 Exam 3 Ch 54: Introduction to Ecology The Biosphere Ecology: the study of interactions among and between organisms and their environment Biotic interactions: interactions among organisms Abiotic interactions: interactions between organisms and their non- living environment o Temperature Uneven sun distribution because of the Earth’s tilt Summer solstice: Northern hemisphere is tilted toward the sun Autumn equinox: Sun’s direct rays fall of the equator Winter solstice: Northern hemisphere is most tilted away from the sun Spring equinox: sun’s direct rays fall on the equator Low: freezes plants High: denatures proteins EX coral reefs and symbiotic algae Some plants require fire for germination Greenhouse effect: The process in which short-wave solar radiation passes through the atmosphere to warm the Earth but is radiated back to space as long-wave infrared radiation Much of this radiation is reflected by atmospheric gases back to Earth's surface, causing its temperature to rise Global warming: a gradual elevation of the Earth’s surface temperature caused by an increasing greenhouse effect o Wind Amplifies effects of cool temperatures (wind chill) and water loss Creates pounding waves Prevailing wind Major winds near the surface of the Earth don’t blow directly north and south because of Earth’s rotation Winds deflect to the right of their original direction in the Northern hemisphere and to the left in the Southern hemisphere Easterlies: winds from the East Westerlies: wind from the West Northeast trade winds (doldrums): from the north() toward the equator Southeast trade winds: from the south() toward the equator o Water Initial pattern of air circulation Warmed by energy from the sun, air at the equator picks up moisture and rises then spreads north and south As the air flows to higher latitudes, it cools and loses moisture as rain o At 30* north and south latitude, the air sinks and flows north and south along Earth’s surface Air rises again at 60* N and S, where air flowing pole- ward meets air coming from the poles At the poles, the cold air sinks and moves toward lower latitudes o Water Insufficient water limits plant growth and animal abundance Excess water drowns organisms High heat capacity Ocean currents Circulates warm and cold waters around the globe Gulf stream o Canada vs England o Light Insufficient light limits plant growth Aquatic environments Photic zone The zone closest to the surface of an aquatic environment where light is sufficient to allow photosynthesis Sunlight is less intense at high latitudes In a higher latitude, light rays pass through more atmosphere In a lower latitude, light rays cover more area o Salinity High salinity reduces plant growth Affects osmosis Species diversity Low in brackish waters and brine High in freshwater and seawater o pH affect decomposition and nutrient availability influences mortality in both aquatic and terrestrial habitats acid rain: precipitation with a pH of less than 5.6 Interactions of wind currents and geography influence climate o Prevailing winds move moisture inland from the Pacific Ocean o Clouds pile up and rain forms on one side of a mountain range facing prevailing winds o Rain shadow on side facing away from the prevailing winds makes arid conditions Rain shadow: an area on the side of a mountain that is sheltered from the wind and experiences less precipitation Seasonal changes in water o Winter Ice covers the thin layer of slightly warmer water just below it Little circulation o Spring Ice thaws; upper water warm and sinks Winds blowing across create vertical currents that overturn water o Summer Sun warms the upper water, which floats on a thermocline (layer across which temperature changes abruptly) Upper and lower water don’t mix because of this thermal boundary o Fall Upper water cools and sinks downward, eliminating the thermocline Vertical currents mix water that was separated during the summer Streams and rivers o More oxygen, less nutrients Marshes and swamps() o Lower oxygen, more nutrients Aquatic desert o Lack of nutrients (clear water) so there is no plankton or other aquatic animals Hydrothermal vents o Primary producers are chemoautotrophic bacteria that obtain energy from hydrogen sulfide o Hydrocarbon seep ecosystem where the primary producers are bacteria that obtain energy from methane Ocean-air interactions o La Nina Warm, moist air ascends; low air pressure; storms in Western Pacific High winds blow west to east Clear skies; dry descending air masses; high pressure Equatorial trade winds blow east to west Upwelling of cold water o El Nino Clear skies; descending air masses; high pressure Trade winds weaken; warm water flows east Warm, moist air ascends; low air pressure; storms High winds blow west Rain falls in central Pacific No upwelling of cold water Biomes: the major types of habitats where organisms are found Environmental science: the application of ecology to real-world problems The scale of ecology o Organism: a single organism o Population: group of the same organism o Community: multiple organisms o Ecosystems: organisms and their environment Organismal ecology: the study of the ways in which individual organisms meet the challenges of the abiotic and biotic environments o Physiological: investigates how organisms are physiologically adapted to their environment and how the environment impacts the distribution of species o Behavioral: focuses on how the behavior of individual organisms contributes to their survival and reproductive success, which, in turn affects the population density of the species Population ecology: focuses on groups of interbreeding individuals called populations o Species interaction: focuses on interactions such as Predation Competition Parasitism o Knowing what factors affect populations helps us Lessen species endangerment Stop extinction Control invasive species o Introduced species (exotic species): species that are moved from a native location to another location, usually by humans o Invasive species: exotic species that spread so aggressively that they crowd out native organisms o Biological control: the use of an introduced species’ natural enemies to control its proliferation o Allelochemicals: a powerful plant chemical that kills other plant species Community ecology: studies how populations of species interact and form functional communities o Why are certain areas species-rich and others species-poor o How species composition and community structure changes over time Succession: the process of change after a disturbance Ecosystem: a system formed by the interaction between a community of organisms and its physical environment Ecosystem ecology: the biotic community of organisms in an area as well as the abiotic environment affecting that community o Deals with the flow of energy and chemical elements within an ecosystem o Food chains Trophic levels: each level of the food chain Food webs: interconnected food chains Scientific Method o Observations o Hypothesis formation o Experimentation o Data analysis o Acceptance or rejection of hypothesis Correlation: a meaningful relationship between two variables o Correlation does not always mean causation Replication: performing the same experiment several times Climate: the prevailing weather pattern in a given region Subsidence zones: areas of high pressure o Tropical deserts Adiabatic cooling: on mountains, temperatures decrease with increasing elevation and increasing elevation leads to a decrease in air pressure Terrestrial and Aquatic habitats are unevenly distributed across the two hemispheres Ocean currents o Rotation of the Earth + wind o “pinwheels” o Gulf stream Aquatic biomes are differentiated by o Water salinity o Current strength o Water depth o Oxygen content o Light availability Terrestrial biomes are differentiated by o Rainfall o Temperature Terrestrial Biomes o Tropical rain forests Lots of rainfall High temperatures Shallow and nutrient-poor soil Equatorial regions Many plant and animal species Canopy allows little light though Few large animals o Tropical deciduous forests Substantial rainfall High temperatures Distinct dry season Soil water shortages Equatorial regions “tropical jungle” on the forest floor high diversity of animal life o Temperate rain forests Abundant rainfall Dense coastal fogs Coastal locales Evergreen trees Mule deer, elk, squirrels, birds, etc. o Temperate deciduous forests Temperatures fall below freezing in winter Lower species diversity Hibernation and migration of animals o Temperate coniferous forests (taiga) Snow Temperatures are very cold for long periods of time Evergreens and conifers o Tropical grassland (savanna) Hot, tropical areas Low seasonal rainfall Extensive dry season Wide expanses of grasses Fire is prevalent Plants with well-developed root system Many large animals o Temperate grassland (prairie) Low rainfall Hot summers and cold winters o Hot desert Little rainfall High day temperatures Low night temperatures Many reptiles o Cold desert Low precipitation (snow) o Tundra Little precipitation Permafrost: a layer of permanently frozen soil Little plant life Cold for most of the year o Mountain ranges Abiotic cooling Aquatic biomes o Intertidal zone Area where the land meets the sea Diverse plant life o Coral reef Limited to the photic zone Warm, tropical waters Species-rich o Open ocean Mostly cold, warming near the surface Upwelling: the circulation of cold, mineral-rich nutrients from deeper in the ocean o Lentic habitat Still, deep water (lake) Oligotrophic: clear with little plant life Eutrophic: rich with dissolved nutrients o Lotic habitat Flowing water (rivers) Little nutrient accumulation Greater oxygen level o Wetlands Areas regularly saturated by surface water or groundwater Marshes and bogs High in animal species o Biography: the study of geographic distribution of extinct and living species o Continental drift: the slow movement of the Earth’s surface plates o Biogeographic regions: Nearctic: North America Neotropical: South America Palearctic: Europe and Russia Oriental: Asia Ethiopian: Africa Australian: Australia o Convergent evolution Population Ecology Ch 56 Population: a group of interbreeding individuals occupying the same area at the same time o Boundaries of a population may correspond to geographic features o Fluid entities Immigrating: moving in Emigration: moving out Demography: the study of birth rates, death rates, age distributions, and the sizes of populations o Size o Density o Distribution o Age structure Density: the numbers of organisms in a given unit area or volume o Finding the density of plants 2 Quadrat: a square frame that encloses an area of .25m Line transect: a long piece of string is stretched out and any tree along its length is counted o Finding the density of animals Suction traps Pitfall traps Sweep nets Mist nets Live traps o Mark-recapture technique: the capture and tagging of animals so they can be released and recaptured, allowing an estimate of population size # of individuals marked in first catch= # of marked recaptures in second total population size catch . total # of second catch Spatial distribution: a pattern of spacing in which individuals in a population are clustered together or spread out to varying degrees o Varies from species to species and from habitat to habitat Clumped: individuals gather into small groups Uniform: individuals maintain a minimum distance between themselves to produce an evenly spaced distribution Random: the location of individuals lacks a pattern Reproductive strategies o Semelparity: organisms produce all of their offspring in a single reproductive event Cohorts: a group of same-aged young that grow at similar rates A stable environment favors semelparity o Iteroparity: reproduce in successive years or breeding seasons Continuous iteroparity: individuals reproduce repeatedly and at any time of the year Age classes are characterized by years An unstable environment favors iteroparity An increasing population should have a large number of young A decreasing population should have few young Life table: provides data on the number of individuals alive in each particular age class o Only includes females because only females produce offspring Survivorship curve: a graphical plot of the numbers if surviving individuals at each age in a population o Type 1: loss of juveniles is relatively low and most individuals are lost later in life Few offspring, but invest much time and resources into raising their young o Type 3: rate for loss of juveniles is relatively high Produce many offspring at one time o Type 2: fairly uniform death rates over time Age-specific fertility rate: the rate of offspring production for females of a certain age o Used to calculate how a population grows Net reproductive rate: the population growth rate per generation Equilibrium: the situation in which the population size stays the same Finite rate of increase: the ratio of the population size from one year to the next o Y= N /N1 0 Change in numbers = births- deaths Change in time Per capita growth rates: determines how populations grow over any time period o Per capita birth rate- per capita death rate Zero population growth: no changes in population size Exponential growth: rapid population growth that occurs when the per capita growth rate remains above zero o G= r x n Growth rate/time = per capita growth rate x number of individuals o EX human population o R= b-d Per capita growth= birth rate- death rate Boom and Bust population pattern o Favorable growth conditions occur: population density increases (boom) o Nutrients are depleted: decline in population density (bust) Intrinsic rate of increase: the situation in which conditions are optimal for a population and the per capita growth rate is at its maximum rate Logistic growth: the growth of a population slows down as it approaches K (carrying capacity) Survivorship curve: the number of survivors by age plotted on a graph Different species have different survivorship patterns Density-dependent factor: a mortality factor whose influence increases with the density of the population o Predation o Competition o Parasitism Density-independent factor: mortality remains unchanged o Physical factors Weather Drought Freezes Floods Fire Inverse density-dependent factor: mortality decreases as a population increases in size o EX. a lion kills the same number of prey no matter how large the prey population gets R-selected species: a high rate of per capita growth, but poor competitive ability o Shorter development o Early reproduction o Fewer breeding episodes Many young per episode o Less parental development per young o Higher mortality rate o Shorter life span K-selected species: have more or less stable populations adapted to exist at or near the carrying capacity of the environment o Longer development o Later reproduction o More breeding episodes Few young per episode o More parental investment per young o Lower mortality rate o Longer lifespan Demographic transition: the shift in birth and death rates that accompanies development st o 1 stage: birth and death rates are high; population is in equilibrium o 2 ndstage: death rate declines first and the birth rate remains high; high growth rate o 3 stage: birth rates drop and death rates stabilize; population grthth rate lowers o 4 stage: both birth and death rates are low; population is in equilibrium Life history affects population growth Pace of demographic transitions depends on o Culture o Economics o Politics o Religion Age structure: the relative numbers of individuals of each defined age group o Population age structure India Shaped like a triangle with point up More young, and less old Sweden Shaped like a rectangle About the same number of each age group Italy Shaped like a triangle with point down There are more old, fewer young China Rectangle at bottom Triangle pointed up at top The younger half has the same number in each age group The older half population gets smaller as age increases The effect of governmental limits the number of children Total fertility rate: the average number of live births a woman has during her lifetime Ecological footprint: the aggregate total of productive land needed for survival in a sustainable world Human populations at equilibrium o High birth and high death rates o Low birth and low death rates Environmental carrying capacity o Growth curve changes from a J to S shape once it reaches the initial carrying capacity Population ecology: focuses on groups of interbreeding individuals called populations o Species interaction: focuses on interactions such as o Knowing what factors affect populations helps us Lessen species endangerment Stop extinction Control invasive species o Introduced species (exotic species): species that are moved from a native location to another location, usually by humans o Invasive species: exotic species that spread so aggressively that they crowd out native organisms o Biological control: the use of an introduced species’ natural enemies to control its proliferation o Allelochemicals: a powerful plant chemical that kills other plant species Ch 57: Species Interactions Types of interactions o Competition: affects both species negatively (-/-) o Amensalism: detrimental to one species and neutral to another (-/0) o Predation, herbivory and parasitism: positive effect on one and negative on the other (+/-) o Mutualism: both species benefit (+/+) o Commensalism: benefits one and leaves the other unaffected (+/0) Competition o Types of competition Intraspecific: between individuals of the same species Interspecific: between individuals of different species Exploitation competition: organisms compete indirectly through the consumption of a limited resource Interference competition: organisms interact directly with one another by physical force or intimidation o Alleolopathy: the suppressed growth of one species due to the release of toxic chemicals by another species o Niche: the unique set of habitat resources a species requires as well as its effect on the ecosystem Competitive exclusion principle: two species with the same resource requirement cannot occupy the same niche Resource partitioning: the differentiation of niches, both in space and time, that enables similar species to coexist in a community Some resource factors o Geography o Habitat o Feeding habit o Size Winter range Fundamental niche: the optimal range in which a particular species best function Realized niche: the actual range of an organism in nature o Sympatric: competitors that occupy the same geographic area Each species specialized on different types of food o Allopatric: competitors that occur in different geographic areas o Character displacement: the tendency for two species to diverge in morphology, and thus resource use, because of competition Predation, herbivory, and parasitism o Herbivory: the nonlethal predation on plants Generalist herbivores: mammals that feed on many different types of plant species Specialist herbivores: insects that are restricted to one or two species of host plants o Predation: results in the death of the prey Anti-predator strategies Chemical defense o Aposematic coloration: warning coloration that advertises an organism’s unpalatable taste o Secondary metabolites in plants Molecules that are produced by secondary metabolism Taste bitter or are toxic Examples Alkaloids o Nicotine in tobacco o Morphine in poppies o Cocaine in coca o Caffeine in coffee Terpenoids o Peppermint Cryptic coloration: the blending of an organism with the background color of its habitat o AKA camouflage o Catalepsis: maintenance of a fixed body posture Mimicry: the resemblance of a species (the mimic) to another species (the model) o Müllerian mimicry: many noxious species converge to look the same, thus reinforcing the basic distasteful design o Batesian mimicry: the mimicry of an unpalatable species (the model) by a palatable one (the mimic) Displays of intimidation o Usually appear larger to deceive potential predators about the ease with which they can be eaten Fighting o Claws, horns, antlers, pincers, stingers Agility o Ease of jumping or gliding helps to escape predators Armor o A strong covering of protection Masting: the synchronous production of many progenies by all individuals in a population to satiate predators and thereby allowing some progeny to survive o Usually found in trees Mechanical: thorns and spines o Parasitism: the nonlethal predation that involves the adult parasite living and reproducing for long periods of time in or on the living host Parasitoids: insects that lay eggs in living hosts Features in common with both predators and parasites because they kill their prey more slowly Parasite: a predatory organism that feeds off another organism but does not kill it outright Host: the prey organism in a parasitic association Holo-parasites: a parasitic organism that lacks chlorophyll and it totally dependent on a host plant for its water and nutrients Hemi-parasite: a parasitic organism that photosynthesizes, but lacks a root system to draw water and thus depends on its host for that function Monophagous: parasites that feed on only one species Polyphagous: species that feed on any different host species Micro-parasites: multiply within their host Macroarasites: live in the host, but release infective juvenile stages outside the host’s body Ectoparasites: live outside the host’s body Endoparasites: live inside the host’s body o Predator controlled system The action of a predator feeding eventually reducing the supply of a prey Invasive species o Donor controlled system Prey supply is determined by factors other than predation, such as food supply, so that the removal of predators has no significant effect on prey density o Host plant resistance: the ability of plants to prevent herbivory via either chemical or mechanical defenses o Herbivores can overcome plant defenses by detoxifying poisons Oxidation Conjugation Mutualism o Trophic mutualism: both species receive a benefit in the form of resources (energy and nutrients) o Defensive mutualism: one species receives shelter or food in return for defending another species Obligatory mutualism: neither species can live without the other Facultative mutualism: the interaction is beneficial, but not essential the the survival and reproduction of either species o Dispersive mutualism: interactions where a species receives food in return for transporting the pollen or seeds of its partner Commensalism o Phoresy: one organism uses a second organism for transport o “Cheating” by mimicking an organism that would give something in return Bottom-up control: the host plant quality or quantity limits the density of herbivores o Nitrogen-limitation hypothesis: organisms select food in terms of the nitrogen content of the tissue Top-down control: the predators limit the number of herbivores, which in turn increases the host plant density Ch 58: Community Ecology Community: the assemblage of many populations that live in the same place at the same time Community ecology: the study of how groups of species interact and form functional communities Organismic model: the view of a community that considers it to be equivalent to a super-organism o Individuals, populations, and communities have a relationship to each other that resembles the associations found between cells, tissues, and organs Individualistic model: considers a community to be an assemblage of species coexisting primarily because of similarities in their physiological requirements and tolerances Principle of species individuality: each species is distributed according to its physiological needs and population dynamics o Most communities intergrade continuously and competition does not create distinct vegetational zones Hypotheses that could explain the distribution patterns of plants and animals on the gradient o Competing species exclude one another along sharp boundaries Other species evolve toward a close association with the dominant species Communities develop along the gradient o Competing species exclude one another along sharp boundaries but do not become organized into groups of species with parallel distributions o Competition does not usually result in sharp boundaries between species The adaptation of similar species to similar physical variables results in the appearance of groups of species with similar distributions o Competition does not usually result in sharp boundaries between species The adaptation of species to similar variables does not produce well-defined groups of species with similar distributions The centers and boundaries of species populations are scattered along the environmental gradient Hypothesis that supports results Species richness: factors that influence the number of species in a community Time hypothesis: communities diversify, or gain species, with time Area hypothesis: larger areas contain more species than smaller areas because they can support larger populations and a greater range of habitats o Species-area effect: the relationship between the amount of available area and the number of species present Productivity hypothesis: the greater production by plants results in greater overall species o Evapotranspiration rate: the rate at which eater moves into the atmosphere through the processes of evaporation from the soil and transpiration of plants, both of which are influenced by the amount of solar energy Intermediate-disturbance hypothesis: the highest numbers of species are maintained in communities with intermediate levels of environmental disturbance o R-selected species are in areas of high disturbance o K-selected species are found in areas with low disturbances o Disturbances by Droughts Fires Floods Hurricanes Herbivory Predation Parasitism Relative abundance: the frequency of occurrence of species in a community Species diversity: a measure of the diversity of an ecological community that incorporates both species number and relative abundance Diversity-stability hypothesis: species-rich communities are more stable than those with fewer species Succession: the gradual and continuous change in species composition of a community following a disturbance o Primary succession: the succession on a newly exposed site that has no biological legacy in terms of plants, animals, or microbes o Secondary succession: the succession on a site that has already supported life but has undergone a disturbance such as a fire, tornado, hurricane, or flood o Climax community: a distinct endpoint of succession o Facilitation: a species makes the environment more suitable for subsequent species o Inhibition: early colonists exclude subsequent colonists o Tolerance: any species can start the succession, but the eventual climax community is reached in a somewhat orderly fashion Early species either facilitate or inhibit subsequent colonists Keystone species: a species on which other species largely depend o If it were removed, the ecosystem would change drastically o Equilibrium model of island biography: the number of species on an island tends toward an equilibrium number that is determined by the balance between immigration rates and extinction rates o The smaller the island, the less species-rich it is o The larger the island, the more species-rich it it o The farther away it is from the source pool, the less species- rich it it is o The closer it is to the source pool, the more species-rich it is Ch 59: Ecosystem Ecology Ecosystem: all of the organisms and their habitat in a given area Ecosystem ecologists study both biotic and abiotic factors Ecosystem ecology: deals with the flow of energy and cycling of chemical elements within an ecosystem Energy flow: the movement of energy through an ecosystem o Energy flow is one-way o Only 1% of solar radiation reaches Earth’s surface Of this, green plants only capture 3% o Producers capture energy from the environment and convert it to stored chemical energy o Primary productivity: the amount of energy made available to the ecosystem by the producers Biomass: the total mass of living matter in a given area Biogeochemical cycles: the movement of chemicals through ecosystems o Nutrients move in cycles Food chain: a linear depiction of energy flow Trophic level: each feeding level in the food chain Autotrophs: harvest light or chemical energy and store that energy in carbon compounds o Producer: the base of the food chain Heterotrophs: consume organic molecules from their environment to sustain life and thus receive their nutrition by eating other organisms o Primary consumers: obtain their food by consuming primary producers o Herbivores: animals that eat plants o Secondary consumers: organisms that eat primary consumers o Carnivores: animals that eat other animals Detritus: unconsumed plants that die and decompose along with the dead remains of animals and animal waste products Detritivores (AKA decomposers): organisms that break down dead organisms from all trophic levels o Most terrestrial food webs are detrital Aquatic food webs are grazing Food web: a complex model of interconnected food chains in which there are multiple links among species o Energy flows from higher trophic levels to lower trophic levels Production efficiency: the percentage of energy assimilated by an organism that becomes incorporated into new biomass o Production efficiency = net productivity x 100 Assimilation Trophic-level transfer efficiency: the amount of energy at one trophic level that is acquired by the trophic level above and incorporated into biomass o Trophic-level transfer efficiency = production at tropic level n x 100 Production at trophic level n-1 Pyramid of numbers: an expression of trophic-level transfer efficiency in which the individuals decreases at each trophic level, with a huge number of individuals at the base and fewer individuals at the top o From top to bottom Tertiary consumers 1 Secondary consumers 90,000 Consumers 200,000 Producers 1,500,000 Inverted pyramid of numbers o Tertiary consumers 5 o Secondary consumers 120,000 o Consumers 150,000 o Producers 200 Pyramid of biomass: a measure of trophic-level transfer efficiency in which the organisms at each trophic level are weighed o Tertiary consumers 1.5 o Secondary consumers 11 o Consumers 37 o Producers 809 [standing crop] Inverted pyramid of biomass o Tertiary consumers 21 o Secondary consumers 4 Pyramid of energy: shows the rate of energy production rather than standing crop o Tertiary consumer 21 o Secondary consumer 383 o Consumer 3,368 o Producer 20,810 Biomagnification: the increase in the concentration of a substance in living organisms from lower to higher tropic levels in a food web Primary production (NPP): the amount of energy available to primary consumers Nutrients: key elements in usable form Limiting factor: a factor whose amount or concentration limits the rate of a biological process or a chemical reaction Secondary production: the productivity of herbivores, carnivores, and decomposers Biochemical cycles: the continuous movement of nutrients such as nitrogen, carbon, sulfur, and phosphorus from the physical environment to organisms and back o Nonliving environmental reservoirs Atmosphere Rocks and sediments Seawater and fresh water Biosphere: the regions on the surface of the Earth and in the atmosphere where living organisms exist The Phosphorus Cycle o Does not have an atmospheric component o Cycles locally o Eutrophication: the process by which elevated nutrient levels in a body of water lead to an overgrowth of algae or aquatic plants and a subsequent depletion of water oxygen levels when these photo-synthesizers decay Global carbon cycle: the movement of carbon from the atmosphere into organisms and back again o Fossil fuels: fuel formed in the Earth from protist, plant, or animal remains, such as coal, petroleum, and natural gas o Living organisms and fossil fuels are carbon “sinks” o Limestone in the Earth’s crust contains a lot of carbon Nitrogen cycle o Nitrogen fixation: nitrogen-fixing bacteria produce ammonia or ammonium from the nitrogen in the atmosphere o Nitrification: nitrifying bacteria oxidize ammonia or ammonium to nitrate ions o Assimilation o Ammonification Decomposers o Denitrification: denitrifying bacteria produce N 2 Water cycle o Evaporation and precipitation o Aquifers: underground water supplies Ch 55: Behavioral Ecology Behavior: the observable response of organisms to external or internal stimuli o A mix of genetic and environmental influences Behavioral ecology: the study of how behavior contributes to the differential survival and reproduction of organisms Ethology: scientific studies of animal behavior Proximate causes: a specific genetic and physiological mechanism of behavior Ultimate causes: the reason a particular behavior evolved, in terms of its effect on reproductive success Innate behaviors (instinctual): behaviors that seem to be genetically programmed o Reflex Fixed action pattern: a behavior that, once initiated, continues until completed o Sign stimulus: a trigger that initiates a fixed-action pattern of behavior Habituation: the form of non-associative learning in which an organism learns to ignore a repeated stimulus Associative learning: a change in behavior due to an association between a stimulus and a response o Classical conditioning (associative): an involuntary response comes to be a associated positively or negatively with a stimulus that did not originally elicit the response Pavlov o Operant conditioning (trial and error): an animal’s behavior is reinforced by a consequence, either a reward or a punishment Cognitive learning: the ability to solve problems with conscious thought o Includes Perception Analysis Judgment Recollection Imagining Learning: behavior modified by experience o Habituation o Conditioning o Imprinting o Observation o Insight learning Critical period: a limited period of time in which many animals develop species-specific patterns of behavior o Imprinting: the development of a species-specific patterns of behavior that occurs during a critical period A form of learning with a large innate component Local movement o Kineisis: a movement in response to a stimulus, but one that is not directed toward or away from the source of the stimulus o Taxis: a directed type of response to a stimulus that is either toward (positive)or away from the stimulus (negative) Migration: long-range seasonal movements o Piloting: an animal moves from one familiar landmark to the next o Orientation: animals have the ability to follow a compass bearing and travel in a straight line o Navigation: the ability not only to follow a compass bearing but also to set or adjust it Foraging: food gathering o Optimal foraging: an animal seeks to obtain the most energy possible with the least expenditure or energy Territory: a fixed area in which an individual or group excludes other members of its own species, and sometimes other species o Can vary in size and use Nesting Feeding Shelter o Defending territory costs energy Communication: the use of specially designed signals or displays to modify the behavior of others o Chemical Pheromones: a powerful chemical attractant used to manipulate the behavior of others o Auditory o Visual Active: something the animal chooses to do Passive: something that the animal already displays o Tactile (touch) o Aggression Threat displays Mayhem Mock combat Often results in a dominance hierarchy Benefits of living in a group o Cooperation Help in locating food sources Assistance in rearing offspring o Better access to mates Increased mating success o Group defense against predators Increased vigilance Protection in numbers o Division of labor Disadvantages of living in a group o Increased risk of competition for resources o Increased risk of disease o Increased visibility to predators Altruism: behavior that appears to benefit others at a cost to oneself o Inclusive fitness: the total number of copies of genes passed on through one’s relatives, as well as one’s own reproductive output o Kin selection: selection for behavior that lowers an individual’s own fitness but enhances the reproductive success of a relative Alarm calls o Eusociality: the vast majority of females (workers) do not reproduce; instead, they help one reproductive female (queen) raise offspring Haploidiploid system Mating systems o Monogamy: individuals mate with one partner Sexual dimorphism: a pronounced difference in the morphologies of the two sexes within a species Mate-guarding hypothesis: males are guarding the female against mating with any other males Male-assistance hypothesis: males remain with females to help rear their offspring Female-enforced monogamy hypothesis: females stop their partner from being polygamous o Polygyny: one male mates with many females Leks: a designated communal courting area in certain species of birds The most attractive males mate with many females o Polyandry: one females mate with many males Sexual selection: a form of natural selection that promotes traits that improve an individual’s mating success o Intersexual selection: one sex chooses mates based on some asset Female choice based on Nuptial gifts Male apperance o Intrasexual selection: males compete and winner “gets the girls” Ch 60: Conservation Ecology Biodiversity: the diversity of life forms in a given location Conservation biology: uses principles and knowledge from molecular biology, genetics, and ecology to protect the biological diversity of life Endangered species: species in danger of extinction Threatened species: species likely to become endangered in the future Extinction: when a species has completely died out Factors that effect species size o Habitat destruction o Desertification o Deforestation o Pollution o Euthrophication o Dead zones o Acid rain o Plastic trash o Ozone depletion o Global warming o Increase of atmospheric CO 2 o Global climate change o Melting glaciers Rise in sea levels o Invasive species o erosion Ways of conservation o Remediation o Habitat preservation o Coastal restoration o Sustainability Reduce Re-use Recycle Ch 45: Nutrition and Digestion Nutrient: any organic or inorganic substance that is taken in my an organism and is required for survival, growth, development, tissue repair, or reproduction Necessities of survival o Energy o Essential nutrients Cannot be synthesized; must be obtained from diet Amino acids Fatty acids Vitamins Minerals Starvation (AKA marasmus) Kwashiorkor: malnutrition because of the lack of protein o Swelling of the belly Vitamin deficiencies cause disease o Pellagra (niacin or B) o Rickets (D) Mineral deficiency can cause disease o Goiter: enlargement of the thyroid gland A balanced diet is important Stages of digestion o Ingestion: taking food into the body via the mouth o Digestion: the breakdown of molecules into smaller components to be used by cells Oral cavity Mastification: teeth breaks down food Salivary gland o saliva soft palate pharynx epiglottis esopgus bolus parastolsis stomach rugae: folds in the stomach hydrochloric acid, pepsisigin chyme small intestines liver and pancreas large intestines colon feces rectum anal canal o Absorption: ions, water, and small molecules diffuse or are transported from the digestive cavity into the circulatory system or body fluids o Elimination: the process by which animals pass undigested material out of the body Suspension feeders o Pump o Trap o Sorter Larger foods must be reduced via teeth o Different teeth based on diet Liquid feeders VIDEO NOTES – BIOMES VIDEO Each have their own plants and animals California o Coast – redwoods, foggy o Inland – canyons, drier o Chaparral o Flat grassland o Pine and fir forests on slopes o East slopes – desert of Nevada Convergent evolution Biome – collection of different ecosystems that are closely related Grassland – field and orchids, woodlands and rivers, also grass… WHAT IS A BIOME 1. THE LARGEST SUBDIVISION OF THE BIOSPHERE 2. TYPE OF ECOSYSTEM SHAPED BY A SPECIFIC CLIMATE AND TOPOGRAPHY 3. A COLLECTION OF SMALLER, SIMILAR AND RELATED ECOSYSTEMS Tundra – lakes, streams, lichens, mosses, shrubs. Bare and rocky ground. Cold and frost. Summer is short (a few weeks) only top few inches or feet thaw… permafrost. Caribou – dominant herbivore, also have reindeer in Eurasia. Musk ox, wolverine, lemming…. Layers of fat, some animals change colors. food chains are simple and limited…. Extreme changes in population size because of extreme temps… ex: owl and lemmings. Northern coniferous forest – mountainous too. Cool summers. Cold winters. Moderate rain. Evergreen, pine, spruce, fir. Bare ground. Squirrels, beaver, porcupine. Can include lakes and streams. Ecological succession – one biome can change into a new, climax community Northwest - Redwoods (tallest plants on earth) are conifers but not part of the north conifer forests Alaska to north cali. Moist temp coniferous forest Because of Pacific Ocean, it is moist. Rain and fog. Cool summer, warm winter 50 inches in fog. 200 inches in WA Not a bare ground. Light can filter through Animals = like north conifer East north America – deciduous – temperate decid. Precip. Moderate temps. Diff seasons. Almost all of the world used to be like this, but a lot has been cut down. Only .5 of 1% is undisturbed. NOT UNIFORM IN SPECIES COMPOSITION --- diff types of trees and animals. A lot of color shows in the autumn leaves when chloro breaks down Grasslands – on all continents except Antarctica … INTERIOR of continents, where rainfall is light Plains – shorter grasses. Not many trees. Many nutrients bc rain is light --- -agriculture Not in north America – tropical savanah – grassland and trees. It is rainy, but there is also a prolonged dry season. Fires are important…. Africa, SA, aust. Only a few species of grass and trees, but a lot of diff mammals. Chaparral – rain, but hot dry summers. Evergreen shrubs, cali, mexico. SA, Aust. FIRE – MAINTAINS THE CHAPARRAL. SOME ARE RESISTANT. SOME SEEDS GERMINATE BY FIRE … IF IT WERENT FOR FIRE, MAYBE TREES WOULD GROW. Plants have long roots and thick leaves, reflective leaves in order to adapt to dryness Desert – light rainfall. Dry descending air masses. Or in rain shadow. Oregon Utah Nevada. Animals have adaptations – cactus. Bloom in spring. Thick skins, dry feces. Nocturnal Tropical rainforest – low latitude regions of equatorial Africa, central/south America, SE asia. Dense plants. Dark. Stratified! 3-9 VIDEO NOTES Desert in the middle of the ocean, but harbors life in variety. Paradox. The Sargasso sea – THE CENTER OF NORTH atlantic. Sea of calm, although surrounding it is wind and moving water. Seaweed drifted here from sea currents Calm. Gulf stream brought sea weed w it UNIQUE COMMUNITY …. Not much movement Few Phytoplankton… because no upwelling or currents, low nutrients – grass that all ocean life eats Clear water – lack of nutrients Low productivity…stable But diverse!!! A lot of zooplankton. Slow evolving species. Extinction is rare Sargasso angler fish – camouflage. Eat shrimp. natural selection has met its demands, angler fish have evolved. Stability. Sargasso weed – where crabs take refuge who are poor swimmers. Find food here too o Weed good, but too much leaves not enough air bubbles, so It sinks… crabs must go to new clump of seaweed Flying fish build nests in the weed… the nest is a mix of threads produced by the female fish.. larvae hidden here o Nothing eats the weed so they are safe Some organisms grow on the weed – barnacles Membonepra , have tentacles When weed dies, the membonepra drift to shore Exoskeleton made of calcium carbonate Anemone eaten by slug Stinging cells to get food NUTRIENT POOR BUT SPECIES RICH 3/11 VOLCANOES OF THE DEEP SEA – VIDEO NOTES Layers of rocks thrust up from the depths of the oceans millions of years ago Found fossil of hundreds of millions of years before dinos… IN SPAIN They send down a deep sea probe Paleodictyon nodosum is a creature thought to produce a certain form of Paleodictyonburrow found around mid-ocean ridge systems in the Pacific and Atlantic Oceans. Although scientists have collected many of the burrows of Paleodictyon nodosum, they have never seen a live one. Midatlantic ridge . Galapagos rift Temperature differential in the water column… found evidence of volcanic process that was building elaborate structures. Water interacted with hot rocks to make black poison chemicals VERY HOT WATER --- ALSO HYDROGEN SULFIDE--- WHY IS THERE ANYTHING LIVING HERE Worm alvinella – could live in the hot water No sunlight after the first few thousand feet Sending down probe and submarine Soft-bodied creatures will never leave behind a fossil… hard to study.. “phantoms of the sea” They are searching where the American and European plates rub together MIDOCEAN RIDGE****** Largest geological feature on the face of the earth Magma rises when the plates move apart. Boils seawater, delivers nutrients to orgs, but also kills them Ex: mexico – many orgs died from the hot lava. New underwater landscape left behind…. Left in ruins Saw weird white spaghetti worms and anemones growing nearby, crabs, octopus, fish, tubeworms, mussels. Featherdusters which filtered nutrients. Not only did life return, but it returned at a great scale. No seasons, no day and night, only driven by inner earth Tall Monolith was found, with tubeworms, which prospered among hottest water, which is near the top At bottom of pilar, tubes, but no worms. Starved to death. the bacteria in the worms were getting chemical energy from stuff in the water and using it to feed the worm, its host. Hydrogen sulfide is fed to the bacteria. This is called chemosynthesis. Red because of blood!! With hemoglobin!!! 5 bya, giant star blew up into supernova. New stars were reignited. Then planets formed Sun isn’t the only source of energy. Earth used to be a star^ still have the energy from this underneath the core of the earth “lost city” – limestone . the bacteria === methane Formed hexagonal patterns --- SURVIVED ONE OF THE BIGGEST MASS EXTINCTIONS Bacteria growing on rocks . use chem energy from hot water to get nutrients to sustain their metabolism Shrimp grazing on rocks use bacteria as food … but the shrimp can get burnt White shrimp – if extremities are burnt off “Houston astrodome” ridge – the bacteria live on the shrimp too, not just the rocks In the chimneys, in total darkness and poisons, high pressure, very hot water, the bacteria are found But still have dna, so we must be related …. Is this where life began Is this where most of the biomass lives Beneath the volcanoes of the deep sea Vent shut off. We don’t know why or how. But now there isn’t much to sustain life… no tubeworms or shrimp This is where they will search for creatures. “Valley of paleodictyon nodossa” Looked at the hexagonal holes and took samples Found no creatures They found out the creature is farming bacteria in the tunnels, so it can live off the remnants of the volcano. So they have outlived all other life on earth. 3/23/16 video notes Black widow - preys on scorpions Kill the prey with silk traps made of silk threads Vibrations in the web will tell her when the prey lands Are they related Or convergent evolution Evolution of behavior 4/4/16 notes --- Animals – nutrition and digestion Why do animals have to eat To get energy from surroundings… except for photosynthetic or chemosynthetic orgs ENERGY --- measured in calories, although not correct sci unit….. This energy is Captured when covalent bonds are broken down, and large molecules are broken down into smaller molecules Also need ESSENTIAL NUTRIENTS (WE CANT MAKE THEM OURSELVES….) … Metals, vitamins, fatty acids, amino acids …Diff orgs have diff essential nutrients IF NOT ENOUGH ENERGY, not enough calories –STARVING… BREAK DOWN MUSCLES to get energy…. This is bad bc if u lose muscle u lose body function…. Bad downward spiral…will probably die IF NOT THE RIGHT NUTRIENTS – other diseases, like Kwashiorkor. Low protein, although enough calories. Don’t have the essential amino acids…. Brittle hair, swollen stomach, HE HAS stordd FAT, BUT CALORIES ARENT THE ONLY THING U NEED TO BE HEALTHY!! 3 world countries Vitamin deficiencies – skin lesions (Pellagra, lack of B vitamin or Niacin), weak bones (put vitamin d in milk to prevent rickets in children) Mineral deficiencies – Goiter (underdeveloped countries) - lack of iodine (thyroid grows larger to try to take up any trace amounts of iodine in body) --- put iodine in salt now to prevent it Dept of agriculture recommends a Balanced diet – fruits, veg, whole grains… less fat and meat Clicker question – A ---Consuming enough Vitamin c prevents scurvy (ascorbic acid in lemon juice) Suspension feeders – remove particles from water. Need to pump, trap, and sort… sponges eat bacteria, filter them from seawater… clams eat unicellular algae and phytoplankton, whales eat shrimp Intracellular digestion –more primitive orgs. The cells lining the digestive cavity take up particles. Particles taken in, digested in lysosomes in cell. Collar cell – in a sponge. Cilia pull water through. Water w bacteria come thru, bacteria are trapped by slits on collar cell, then taken up and digested inside. Extracellular – more advanced orgs. Specialized cells lining the digestive tract that can secrete enzymes. Some animals have both types of dig (intra and extra) DIGESTION VIDEO -- DIGESTION – THE BREAKDOWN OF FOOD and ABSORPTION OF NUTRIENTS --Start in mouth… “Mastication.” Also saliva (CONTAINS AMALASE AND MUCUS) moisten food and starts chem digestion… Soft palate blocks upper throat and nasal cavity… Voluntary muscles pass food down thru pharynx… Epiglottis covers trachea…. Food goes to esophagus. Food now called bolus. Bolus moves by peristalsis (involuntary)… bolus now in stomach. Stomach expands by rugae as it fills. HCl, pepsinogen, and reg hormones secreted. Chemically digest bolus. Bolus churned and mixed with liquid into chime. Chime exits via pyloric sphincter and enters SI, where nutrients are absorbed. 3 parts of SI – duodenum, jejunum, and ilium… bile from liver, and enzymes from pancreas enter duodenum. Nutrients absorbed into the blood and lymph. Nutrients not absorbed pass into LI, via cecum, ascending, transverse, descending, and sigmoid (parts of LI) colon. Water and salts absorbed. Chime is now feces … stored in rectum. Eliminated via anus. --Smooth, involuntary muscle lines the entire digestive tract. Controlled by nerves and hormones. Video #2 – Hcl made in parietal cell. Co2 diffuses into parietal cell. Co2 and water make carbonic acid (via an enzyme). This becomes bicarbonate ion and H+. bicarbonate ion goes back into bloodstream. Ion exchange molecule moves bicarbonate out when chloride comes in. THIS IS A SECONDARY antiport ACTIVE TRANSPORT PROTEIN… H+ actively goes in to duct of gastric gland, and cl- diffuse in with H+. potassium ions are countertransported into parietal cell in exchange for H+ ions. Net result = hcl made in parietal cell and its secretion into the gastric gland.. Clicker question – B Bile made in liver, stored in gall bla