FINAL EXAM: BISC 12 Study Guide Midterm 2 Chapter 54 (1-2)---Community Ecology o Interspecific interactions- interactions with other species Competition (-,-) Competitive Exclusion- G.F. Gause- two species cannot coexist permanently in the same community if their niches are identical o One species will use resources more efficiently and thus reproduce more rapidly which this slight reproductive advantage will eventually lead to the local elimination of the inferior competitor. Ecological niche- sum of a species use of biotic and abiotic resources in its environment Resource partitioning- the differentiation of niches that enables similar species to coexist in a community (species modify their niches to survive- natural selection) Fundamental niche- the life pattern that the organism should have under ideal conditions Realized niche- the life pattern that the organism actually assumes due to scarcity competition, etc Allopatric- geographically separate Sympatric- geographically overlapping Character displacement- the tendency for characteristics to diverge more in sympatric populations of two species than in allopatric populations of the same two species Predation (+,-) Adaptations are seen from both predator and prey o Cryptic coloration- camouflage o Aposematic coloration- warning coloration o Batesian mimicry- a palatable or harmless species mimics an unpalatable or harmful model To work the predator must be able to learn to recognize the model and the model needs to outnumber the mimic o Mullerian mimicry- two or more unpalatable/harmful species resemble each other (advantage if the more unpalatable prey

there are, the more quickly the predator learns to avoid them) ***Predators also use mimicry snapping turtles tongue looks like worm Herbivory (+,-) Most herbivores are actually invertebrates (grasshoppers and beetles) Predators adapt- chemical sensors to tell toxicity, sense of smell, eating only specific parts like flowers Prey adapt- plants arsenal includes- chemical toxins and structures such as spines and thorns Symbiosis- two or more species live in direct and intimate contact with one another Parasitism- (+, -) one organism (parasite) derives its nourishment from another organisms (host), who is harmed in the process o Endoparasites- within the body of the host (tapeworms) o Ectoparasites- feed on the external surface of the host (lice) o 1/3 of all species are parasites o Significantly affect the survival, reproduction, and density of their host population, directly or indirectly Mutualism/Mutualistic symbiosis- (+, +) o Obligate mutualism- at least one species has lost the ability to survive without its partner o Facultative mutualism- both species have ability to survive alone, but benefit from the other Commensalism- (+, 0)o Difficult to document because any close association usually affects both species (if only slightly) o Hitch-hikers such as algae and barnacles, usually considered commensal, but may slow down whale/turtle and provide camouflage o Secondary compounds- chemicals that arent part of metabolism for plants but used as defense (also in bees, etc) o Intraspecific interactions interactions within a single species o Species Diversity- the variety of different kinds of organisms that make up the community Species richness- the number of different species in the community Relative abundance- the proportion each species represent of all individuals in the community

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Shannon diversity (H): H= -[(pA ln pA)+ (pB ln pB)+( pC ln pC)] o ABC= species p= relative abundance Trophic Structure- feeding relationship between organisms (movement of energy and matter through an ecosystem) Primary Producers- plants and other autotrophs Primary Consumers- herbivores Secondary consumers- carnivores Tertiary/quaternary/etc- carnivores Decomposers Charles Elton- food web- interconnected feeding relationship (diagrammed by who eats whom) A given species can weave into the web at more than one trophic level (omnivores) Humans are the most versatile omnivores Two ways to simplify food webs 1) Group species with similar trophic relationships in a given community into broad functional groups (ex. 100 phytoplankton are grouped as the primary producers) 2) Isolate a portion of the web that interacts very little with the rest of the community Food chains are relatively short (rarely more than 7 links, usually >5) Energetic hypothesis- length of the chain is limited by the inefficiency of energy transfer along the chain (only 10% of the energy stored in the organic matter of each trophic level is converted to organic matter at the next trophic level) Dynamic stability hypothesis- long food chains are less stable than short food chains Population fluctuations at lower trophic levels are magnified at upper levels, potentially causing local extinction of top predators, longer food chains are the more slowly top predators can recover from environmental setbacks *** Most data supports energetic hypothesis Dominant Species- those species in a community that are the most abundant or that collectively have the highest biomass Biomass-the total mass of all individuals in a population Exert a powerful control over the occurrence and distribution of other species Why a species becomes dominant Competitively superior in exploiting limited resources Most successful at avoiding predation or the impact of disease

o Keystone species- not necessarily abundant in a community but they exert strong control on community structure by their pivotal ecological roles or niches. Identified by removal experiments Help maintain the diversity of a community o Foundation species/ ecosystem engineers- alter their physical environment on a large scale through their behavior or their large collective biomass (ex. beaver) Facilitators- positive effects on the survival and reproduction of other species o Bottom-up model- VH - unidirectional influence from lower to higher trophic levels If you add predators or remove predators from this community the effect should not extend down to the lower trophic levels o Top-down model (aka trophic cascade model)- postulates that predation mainly controls community organizations because predators limit the number of herbivores, herbivores limit plants, and plants limit nutrient level Biomanipulation-attempt to prevent algal blooms and eutrophication by altering the density of higher level consumers in lakes instead of chemical treatment Chapter 55 (4-5) o Life on earth depends on the recycling of essential chemical elements (scarcity) o Biogeochemical cycles- any of the various chemical cycles that involve both biotic and abiotic components. Global- gaseous forms of carbon, oxygen, sulfur, and nitrogen occur in the atmosphere Local-other elements like phosphorus, potassium and calcium are to heavy to occur as gas so cycle more closely o Decomposition is controlled by factors such as temperature moisture, and nutrient availability. Usually grow faster and decompose material more quickly in warmer temperatures Tropical rainforest-organic material decomp in few months/years (75% of nutrients in ecosystem are in the woody trunks of trees, 10% in soil)--- result of short cycling time Temperate forest- organic material decomp in four to six years (as much as 50% in soil) o Result of higher temperatures and more rain in rainforest o Most chemical cycles are now influenced more by human activities than by natural processes

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Human activity often removes nutrients from one part of the biosphere and adds them to another Nitrogen is the main nutrient lost through agriculture agriculture has a great impact on the nitrogen cycle Human activity has more than doubled Earths supply of fixed nitrogen available (with industrial fertilizer providing the largest additional nitrogen source) Nitrogen enters ecosystem as nitrate (sometimes ammonium) Fossil fuel combustion and increased cultivation of legumes also increases nitrogen levels Critical load- the amount of added nutrient (usually nitrogen of phosphorous) than can be absorbed by plants without damaging the ecosystem integrity. Nutrient runoff can also lead to the eutrophication of lakes Eutrophication- the addition of nutrients and artificial/nonartificial substances through fertilizers and sewage into any habitat Usually referring to lakes, oceans, etc. which results in the blooms of phytoplankton The burning of wood and fossil fuels (coal and oil) release oxides of sulfur and nitrogen that react with water in the atmosphere to form sulfuric acid and nitric acid. Creates precipitation that has a pH less than 5.2 This lowers the pH of streams and lakes and effects soil chemistry and nutrient availability Occurring since the Industrial Revolution Acid precipitation is a regional problem arising from local emissions 1980- pH of precipitation in N. America and Europe averages 4.0-4.5 Causes calcium and other nutrients to leach from the soil, which affects the health and growth of plants Can also directly affect plants by leaching nutrients from their leaves Freshwater ecosystems with low concentrations of bicarbonate are the most readily damaged by acid precipitation Experiments being carried out to test the feasibility of reversing effects of acid rain are the Hubbard Brook idea of CA+2 addition and covering a forest with a glass roof and showered the forest with clean precipitation Sulfur dioxide emissions decreased 31% in the US between 1993 and 2002, but nitrogen oxides are increasing Biological magnification- a process in which retained substances become more concentrated at each higher trophic levels in a food

chain (ex. mercury which is turned into methylmercury)top-level carnivores tend to be the organisms most severely affected by toxic compounds Chlorinated hydrocarbons (PCB) and pesticides (DDT) DDT involved in decline of pelicans ospreys and eagles because it interfered with the deposition of calcium in their eggshells so when parent would sit on eggs, they would break- Rachel Carson Silent Spring o Concentrations of CO2 in the atmosphere have been increasing from fossil fuels and deforestations by about 40% from the mid-19th century, if this continues then by 2075 the concentration will be more than double than it was at the start of the Industrial Revolution Increased productivity of plants is on predictable consequence of increasing CO2 levels (help C3 species like wheat and soybeans when today C4 like corn are usually favored) FACTS-I: Forest-Atmosphere Carbon Transfer and Storage (1995)- experiment at Duke University to assess how the increasing atmospheric concentrations of CO2 might affect temperate forests by manipulating the concentration that trees are exposed to Increase CO2 plots produced 15% more wood each year o Greenhouse effect- the warming of Earth due to the atmospheric accumulation of carbon dioxide and certain other gases, which absorb reflected infrared radiation and reradiate some of it back toward Earth Support for this is the correlation between CO2 levels and temperatures The ecosystem where the largest warming has already occurred is those in the far north, particularly northern coniferous forests and tundra. Analysis of fossilized pollen indicates that plant communities change dramatically with changes in temperature Many organism, especially plants, cannot disperse rapidly over long distances may not be able to survive the high rates of climate change projected, especially because many habitats are more fragmented than they were in the past limiting migration o Earth is protected from the damaging effect of UV radiation by a layer of ozone molecules O3 located in the stratosphere (17-25 km above Earths surface) Thinning since mid 1970s Results from accumulation of chlorofluorocarbons (CFCs) used to be in refrigerators and manufacturing CFCs rise to stratosphere and react with ozone reducing it to molecular O2 subsequent reactions liberate the

chlorine allowing it to react with other ozone chain reaction Most apparent thinning over Antarctica in spring At the more heavily populated middle latitudes, ozone levels decreased 2-10% in the past 20 years Decrease in ozone levelsincrease in intensity of UV rays UV radiation can cause DNA damage 1987- 190 countries signed the Montreal Protocol that regulates the use of ozone-depleting chemicals Many countries banded production of CFC o Even if CFC were globally banned today, the chlorine already in the atmosphere would continue to influence stratospheric levels for at lease 50 years. Chapter 56 (2-3, 5) o Conservation at the population and species levels Small-population approach Declining population approach o Small population approach Study the process that causes extinctions once population sizes have been severely reduced Extinction vortex- a downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and, unless the spiral is reversed, to become extinct (positive-feedback loops) Key issue is the loss of genetic variation necessary to enable adaptations to environmental change In some rare cases, low genetic diversity has not impeded population growth (northern elephant seals with only 20 individuals- bottleneck effect) Minimum viable population (MVP)- the minimal population size at which a species is able to sustain its numbers and survive Often used in population variability analysis to predict a populations chances of survival over a particular time interval o One of first viability analysis on grizzly bears Effective population size- based on the breeding potential of the population Ne = (4Nf Nm)/(Nf + Nm) Nf =number of females Nm = number of males This effective population is equal to the idealized population if every individual breeds and the sex ratio is 1:1 o Declining Population Approach-

Focuses on threatened and endangered populations that show a downward trend, even if the population is far above MVP Different than small population approach because: Small population emphasizes smallness itself as an ultimate cause of a populations extinction (especially through loss of genetic diversity). Declining population approach emphasizes the environmental actors that caused a population decline Requires evaluation on a case to case basis o Weighing Conflicting Demands Habitat use is almost always the issue Mining jobs or habitat for timber wolves and grizzly bears? Because we wont be able to save every endangered species, we must consider the ecological role and determine keystone species to save Conservation must look at the whole community/ecosystem not just a single species o Sustainable development- development that meets the needs of people today without limiting the ability of the future generations to meet their needs o Sustainable Biosphere Initiative- Ecological Society of America- to define and acquire basic ecological information needed to develop, manage and conserve Earths resources are responsibly as possible. Lecture Life is o o o o o o o

Order Adaptation Response to stimuli Homeostasis Metabolism Reproduction Growth and development ***Does not require oxygen

Population- a group of individuals (aka subset of a species) of the same species occupying a given area Community- all the organisms that inhabit a particular area (living close enough for potential interaction) Ecosystem- all biotic and abiotic factors Biosphere- largest category, all ecosystems, aka Earth Scientific Law vs. Theory o Scientific Law- description of an observed phenomenon (Newtons Law of Gravity- Falls) o Scientific Theory- explanation behind the observed phenomenon Hypothesis can never be proven right o Reject or Fail to Reject Batesian mimicry- a type of mimicry when a harmless species looks like a species that is poisonous or unpalatable (different snakes) Mullerian mimicry- mutual mimicry by two dangerous/unpalatable species (bees, wasps, etc.)

Chapter 1---Study of Life Evolution- the process of change that has transformed life on Earth from its earliest beginnings to the diversity of organisms living today, it is the fundamental organizing principle of biology and the main theme o Creates diversity Biology- the scientific study of life, posing questions about the living world and seeking scientific base answers are the central activities Emergent properties- new properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases o Not unique to life Discovery science (descriptive science)- describes natural structures and processes as accurately as possible through careful observation and analysis of data. Chapter 52---Ecology and the Biosphere Ecology- (oikos- home + logos-study) the scientific study of the interactions between organisms and the environment o Environment influences organisms and organisms influence their environment o Study of the abundance and distribution of organisms o Roots are in discovery science o Henry David Thoreau- coined the term ecology Different levels of Ecology o Organismal- concerned with how an organisms structure, physiology, and behavior meet the challenges posed by the environment o Population- analyzes factors that effect population size and how +why it changes through time

o Community- how interactions between species affect community structure o Ecosystem- emphasizes energy flow and chemical cycling between organisms and the environment o Landscape- focuses on the factors controlling exchanges of energy, materials, and organisms across multiple ecosystem o Global- how the regional exchange of energy and materials influences the functioning and distribution of organisms across the biosphere Biotic factors- living factors- all organisms that are a part of the individuals environment Abiotic factor- nonliving factors- all the chemical and physical factors, such as temperature, light, water, and nutrients, that influence the distribution and abundance of organisms Species transplant o used to determine if dispersal is a key factor limiting the distribution of a species o to be successful, some organisms must not only survive in the new area but also need to reproduce there successful potential range of the species is larger than its actual range aka the species could live in certain areas where it currently does not If behavior does not limit the distribution biotic? abiotic?

Chapter 53--- Population Ecology Population Ecology explores how biotic and abiotic factors influence the density, distribution, size, and age structure of populations Population- a group of individuals (aka subset of a species) of the same species occupying a given area o Rely on same resources, influenced by similar environmental factors, and likely to interact and breed with one another o POPULATIONS CAN EVOLVE NOT SPECIES OR INDIVIDUALS Density and Dispersion o Density- the number of individuals per unit are or volume o Dispersion- the pattern of spacing among individuals within the boundaries of the population

o Usually impractical or improbable to count all individuals within a population use sampling techniques to estimate density Patterns of Dispersion Most common pattern of dispersion= clumped Survivorship Curves- a plot of the proportion or number in a cohort still alive at each age o Type 1- Flat at the start, then steep drop Many mammals, including humans, have this curve (few offspring, but lots of care) o Type 2- line with constant slope (straight line)- constant death rate Squirrels, rodents, some lizards, some plants o Type 3- steep drop at beginning (high death rates of the young) then flattens out as death rates decline Organisms with large # of offspring but little care (fish)

Elephant- Type 1, Bird- Type 2, Insect- Type 3 Reproductiono Semelparity (big-bang reproduction)- reproduce all at one time (salmon) Favored when the survival rate is low

o Iteroparity- (repeated reproduction)- from a certain maturity, produce annually/repeatedly (lizards) Favored in a more dependable environment where competition may be intense ***trade-off between reproduction and survival Changes in Population Sizes o Birth and Death o Immigration and Emigration Per Capita Rate of Increaseo Change in population size during time interval = (births during time interval +immigrants entering during time interval) (deaths during time interval + emigrants leaving during time interval) Abbreviated (dropping the immigration/emigration N/t= bN dN b= per capita birth rate o (#birth/per time interval) total number present d= per capita death rate N= population size t=time per capita rate of increase r=bd o r > 0 = population is growing o r < 0 = population is declining Simplified: N/t= rN Zero Population Growth (ZPG) occurs when the per capita birth and death rates are equal (doesnt mean there are no births and death, just means they are equal)

Biotic Potential ( rmax or intrinsic rate of increase) maximum rate of increase per individual under ideal conditions

Exponential Population Growth (aka geometric population growth)-growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time (max rate of increase is constant) o dN = rmaxN dt o Assumes that resources are unlimited (not realistic) Carrying capacity (K)- the maximum population size that can be supported by the available resources o Limiting Factors- lead a population growth towards K, an essential resource in short supply Logistic Population Growth- population growth that levels off as population size approaches carrying capacity, S-shaped curve o dN =rmax N (K-N) dt K

Overshooting Capacity-

K-selection- selection for life history traits that are sensitive to population density (density-dependent selection) o Operate in a population living at a density near the carrying capacity where competition among individuals is relatively strong Stable Limited by carrying capacity Organisms- larger, long-lived, fewer offspring w/ more care

R-selection- selection for life history traits that maximize reproductive success in uncrowded environments (density-independent selection) o Maximizes r and occurs in environments in which population density is well below carrying capacity or individuals face little competition (often found in disturbed habitats) Unstable Limited by reproductive rate (r) Organisms- smaller, short-lived, lots of offspring with little/no care

Density-Dependent-varies according to density o Competition for resources o Territoriality- competition for space

Disease-depends on certain level of crowding Predation Toxic wastes (by-products) Intrinsic (physiological) factors Aggressive interactions, stress sex-related issues, increased mortality due to crowding Density-Independent- does not vary due to density o Catastrophes o Natural disasters o Diseases- that act at ANY population size Population Dynamics- focuses on the complex interaction between biotic and abiotic factors that cause variation in the size of the population Human Population o 6.6 billion people o Increasing by 75 million a year (1.26%) o Demographic transition= Zero population growth= low birth rate-low death rate Key is reduced family size o Age-structure pyramids Rapid growth= bottom heavy triangle (Afghanistan) Slow growth= relatively even (US) No growth= top heavy (Italy) ***Not only predicts a populations growth trends but also illuminates social conditions o Ecological footprint- the aggrefate land and water are required by a person, city or nation to produce all of the resources it consumes and to absorb all of the waste it generates (used to estimate the worlds carrying capacity) o Todays Environmental Problems Habitat Loss Invasive Species Populations Growth Pollution Overuse of resources Chapter 22-24 Keystone species- when removed from habitat, many other organisms die off Species Richness- how many species Diversity- how many of each species Two principles lie at the core of the science of evolution o Common descent w/ modifications o Natural selection It maintains favorable genotypes in a population Shapes evolution, not design Scientists o o o o

o Alfred Russel Wallace- developed a natural selection hypothesis similar to Darwin, but admired/thought Darwin had developed the idea so extensively, he let Darwin be the main architect o Charles Lyell (1830)- earth is changing (uniform rate of change, same things happening now were happening millions of years ago) o JB de Lemarch (1809)- species change due to inheritance of acquired characteristics, modifications passed to offspring o George Cuvier (1769-1832)- fossils, developed paleontology o Darwin- Decent with Modification Evidence for Evolution- lines of evidence internally consistent and consistent with each other o Fossils o Comparative anatomy/ homologous structures o Direct Observation o Biogeography- geographic distribution of the species o Molecular- genetic code Evolutionary Fitness- number of offspring left behind Herbert Spenser- survival of the fittest Artificial selection- when human being choose organisms with specific characteristics (stock), humans are performing the role of the environment Hardy and Weinberg Equilibrium Principle: We have gone from allele frequencies in the parental gene pool to genotype frequencies among the offspring o p+q=1 o p2 + 2pq + q2 = 1 Assumptions: No migration No mutations No chance events No natural selection No non-random mating Evolution takes place when the allele frequency in a population changes o 5 agents of microevolution Mutations: