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173 Cards in this Set
- Front
- Back
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What is the biogenetic law
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ontogeny recapitulates phylogeny
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What does the biogenetic law mean
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as an organism goes through it's development, it repeats the adult stages of its evolutionary past
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What did Europes early plant ecologists do?
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concerned with desribing plants communities
-ex: deriving methods for communitiy sampling, analyzing data, classifying plant communities with nomenclature |
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What did early plant biologists in the US do?
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interested in HOW plant communities develop and how they change after disturbance
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What is zoogeography
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the study of the distribution of animals and reasons for those distributions
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What is ethology
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the way animals behaved under normal behavior
-descriptive approach -ex: comm.,nav, bio clocks, imprinting, conditioning |
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What is behavioral Ecology
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adaptive role of behaviors shaped by natural selection
-the way animals interact with environment -how an observed behavior has been influened by nat. selection to be adaptive -ex: ways animals avoid predators, live in groups, establish territories, find mates, and decide what to eat |
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physiological ecology
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Branch of ecology concnered with ways in which individual organisms interact with their abiotic environment
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What is the area of focus of chemical ecology
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certain organisms use chemical substances for defence
-some plants produce compounds that inhibit growth of associated species |
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What did Malthus contribute?
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-Principle that pop grow geomet. while food supplies increase arithmet.
-inescapable conclusion that all populations will eventually outstrip their food supply -they must be controlled by pred, disease, and famine He foreshadowed the field of pop ecology inspriation for darwin's nat selection |
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What is limnology
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study of freshwaters
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The paper "trophic-dynamic aspects of ecology" by lindeman marks the beginning of what branch of ecology?
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ecosystemecology
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What are the goals of theoretical ecology?
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to understand how individuals, populations, and communities interact with their natural environements
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What are the goals of applied ecology?
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seek to find ways to solve economic problems
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What is the focus of conservation biology?
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utilize both theoretical and applied ecology to address problems with habitat destruction and loss of diversity
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What is landscape ecology
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branch of ecology concerned with earth's spatial patterns and how they develop
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What is restoration energy?
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applies ecological principles and experimental research to try to restore disturbed habitats to their former states
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What is the "great unifying principle of biology?"
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evolution by natural selection
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What is evolution
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change in gene frequencies
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Evolution always involves....
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a change in gene frequences
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What is the Hardy-Weinberg Equilibrium?
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"in the absence of forces that change gene frequencies, in a large, randomly mating population, gene frequencies should remain the same from generation to generation"
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What is random mating?
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individuals show no preference with respect to mate selection based on the trait
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What is the role of mutation in the process of evolution
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raw material for evolutionary change
-ultimate source for genetic novelty |
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What is the role of genetic recombination in the process of evolution
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most imp. source of heritable variation upon which natural selection acts in sexually reporducing organisms because of its potential to amplify existing variation
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What are 2 points during meiosis in which genetic variation can be introduced in the genome?
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prophase 1: crossing over
Anaphase 1: random segregation of homologous chrom |
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How can sex result in the reduction in an individuals contribution of genes to the next generation
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gametes only contain 50% of your genes
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What is recombinational load?
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the production of many individuals with unfit combos of genes
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What are two possible advantages to individual fitness that sex might provide?
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-repair of damaged DNA through recombination
-masking deleterious mutation through outcrossings (if one doesn't work, the other will and will get masked by the dominant) |
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In a closed population what two forces can lead to a change in gene frequencies?
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-natural selection and genetic drift
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What is natural selection
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differential reproduction
-certain genotypes leave more offspring to the next generation than others -NOT survival of the fittests |
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What is stabilizing selection
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if environment is stable over time, extreme phenotypes may be selected against
-ex: having too long or too short of wings |
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What effect does stabilizing selection have on phenotypica variation in a population
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tends to reduce phenotypic variance and counter the effects of mutation, genetic drift, and gene flow from other population
-doesn't lead to a change in mean values over time |
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What is directional selection and give an example from nature
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if environment is changing in directional fassion, selection may act against one extreme phenotype or the other
-ex: peppered moth |
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What is disruptive selection and what is a possible outcome
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if environemnt is heterogeneous enough, selection may favor both ends of the phenotypic range
-intermediate forms are selected against -results in genetic polymorphism: 2 diff phenotypes -ex: having a short or long beak helps get food |
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What is genetic drift
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random changes in gene frequences that occur in small population due to sampling error
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Under what conditions is genetic drift most likely?
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-small populations
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What is the "founder effect"
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when a few individuals emigrate and begin a new population
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What is transient polymorphism?
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the frequence of alleles or phenotypes change over time
Ex: freq of light and dark moths in great britain |
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What is balanced polymorphism
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The freq. of two or more alleles or phenotypes remain stable over time
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What are three ways that balanced polymorphism can be maintained
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1. Neutral allelels: individuals with diff alleles don't differ in their fitness
2. Heterozygous advantage: if hetero is favored, both alleles will be maintained 3. environmental heterogeneity: one phenotype favored depending on environ, season, hab., etc. |
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What is genetic drift?
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random changes in gene freq in small populations
-can lead to evolution but not usually adaptive cuz its so random -like nat. selection, it also leads to reduction in genetic variability as alleles are lost or fixed |
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What is an example of balanced polymorphism through hheterozygote advantage
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Homozygous sickle cell anemia: die
Heterozygous: slight anemia but are immune to malaria -SO...they have higher fitness and leave more offspring behind than those w/o sickle cell genes |
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What type of adaptation is seen in the evolution of melanism in peppered moths in UK?
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Differential survival occurs in diff habitats
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Define the term "fitness"?
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measure of the number of offspring left by an individual (genotype) relative to the ideal (reference) genotype in a population
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What range of values can W assume?
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LOOK THIS UP
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How is fitness calculated
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dark moths were ideal so they have fitness of 1.00 even though survival rate only 0.53
0.25 is survival rate of light: 0.25/.53= fitness of 0.47 |
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What are three reasons why organism may not be perfectly adapted?
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1. Availability of adaptive genes
-something hasn't come around yet 2. opposing selection pressures -ex: bright colors attract males but make them more visible to pred. 3. environmental change -change in physical conditions -they keep needing to make evolutionary changes |
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What is the "red queen hypothesis"
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they have to keep making evolutionary changes just to stay alive.
-having to keep running hard just to stay in place |
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Under most circumstances, what is the target of selection?
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the individual
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What are the altruistic traits?
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traits promoted by group selection
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How might altruistic traits be selected for?
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group selection known as kin selection
-acts of altruism in a closely related group may lead to increase of an individuals genes being passed on.__________________________ |
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According to the "optimal foraging theory", how should consumers forage for food?
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in a way that maximizes their caloric intake per unit time or effort
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How should natural selection affect two species that are potential competitiors
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organisms should evolve ways of avoiding direct competitors
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What is sympatric populations
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two populations are found together
-they overlap their ranges |
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What are allopatric populations
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two populations are not found together
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What is the first step in the process of allopatric speciation
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populations can get fragmented by a barrier (mountain, river) into two or more subpopulations
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Provide two ways in which populations separated by a barrier might diverge genetically
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-different selection pressures
-genetic drift |
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Define adaptive radiation
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generation of a number of different forms from a basic stock
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Give an example of adaptive radiation in nature
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Galapagos finches
-they found environments with many vacant niches -took place among mammals after dinosaurs were gone |
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According to Ernst Mayr, biological species are...
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species are groups of interbreeding organisms that are reproductively isolated from other such groups
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Reprodcutively isolateing mechanisms are...
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properties found within an organism that prevent them from interbreeding with other organisms
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are rivers, canyons, mountain ranges, etc. considered reproductive isolating mechanisms?
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No because they are not found within the organism
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How can premating isolating mechanisms be improved by natural selection?
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selection against less fit hybrids
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What is behavioral isolation
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premating isolating mechanism
-having different courtship patterns |
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What is temporal isolation
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premating isolating mechanism
-breeding at diff times during the year |
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What is ecological isolation
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premating isolating mechanism
-breeding in different habitats |
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What is an example of postmating isolating mechanism
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hybrid sterility
-back up for if premating isolating mech fail |
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Can postmating isolating mechanisms be improved by natural selection? why/how/how not
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no because you can't make two hybrids be together to become sterile????
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what is the probable function and meaning of biological species
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-through reproductive isolation, species become adapted to their own ecological niches
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How do environmental conditions differ from environmental resources?
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-conditions are abiotic envir. factors that vary in space and in time and to which org are diff responsive
-Ex: temp, pH -may be mod by other org (ex: pH may change if plants present -cond not consumed -resources: things that are consumed |
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What is a homeotherm? ex?
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maintain constant body temp
-birds and mammals -many reptiles |
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What is a poikilotherm?? Ex?
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have body temp that vary passively with surrounding (ambient) temps
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What is an ectotherm? Ex?
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Organisms that use external heat sources to regulate body temp
-amphibians, reptiles, fish, insects |
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What is an endotherm? Ex?
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Use internally-produced heat to regulate temp
-many birds and mammals -bees moths, butterflies are endothermic when active |
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What factors influence the amount of solar radiation absorbed by an animal?
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time of day, amount of dust, amount of clouds, color of organism
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Under what conditions does thermal radiation flow into an animal's body?
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if surroundings are warmer than the organism
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what is convection and what is its importance for heat exchange in animals?
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heat transfer from an object to a fluid that surrounds it
-if org hotter than fluid, heat lost |
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What parameters determine the direction and effectivness of convectional heat exchange between an animal and its surroundings?
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if animal is hotter than surounding fluids, heat will be lost
-rate of exchange increases with diff between animal temp and surroundings -depends on shape of animal (surface area -windspeed |
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How might an animal modify the amount of heat lost or gained by convection?
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change surface area
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What is conduction
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heat exchange through physical contact with the animal and its substrate
-ex: reptiles on warm roads |
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how do animals lose heat by evaporation
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respriatory surfaces or sweat glands
-heat loss not very good if air is humid |
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what is required for an animal to use metabolic heat for thermoregulation?
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-produced through cellular respiration and other metabolic processes
-they need some form of insulation |
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What kind of fixed properties might influence the amount of heat gained by solar radiation in ectotherms?
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-reflective or shiny leaves in desert plants
-dark wing-pigmentation in alpine butterflies |
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What kind of behavioral and physiological repsonse might an ectotherm use to regulate body temperature
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-parallel or perpendicular basking
-shuttling back and forth between shad and sun -changes in peripheral blood flow |
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Give three reasons why an ectotherm might not regulate its body temp
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-regulatory power is limited
-are dependent on external heat sources and can only use them if they are available -costly: Ex: shuttling back and forth may make them more at risk for predation |
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What does Q10 represent
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temperature coefficient
-increase in metabolic rate for a 10 degree C rise in temp |
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What is acclimatization?
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adjustments made in nature to compensate for colder temps
-ex: mod in enzyme systems |
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What is acclimation
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adjustments induced under lab conditions
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What is freeze resistance
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-protect down to temp inexcess of -40 degrees C.
-it is a gamble -cuz water is solid |
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What is freeze tolerance
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-protect down to -8 degrees C
-procuce high concentrations of glucose or glycerol -or reduce water content of body |
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What are two possible lethal consequences of high temps for living organisms
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-inactivation of enzymes
-dehydration |
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What are thermophilic procaryotes and where do they live
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heat tolerant organisms that exist in hot springs
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In what habitat characterized by high temp and pressures might you find chemosynthetic bacteria
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superheated deep-water oceanic vents called "smokers"
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What is a thermoneutral zone of an endotherm?
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Over the temp that they can maintain a basal metabolic rate and when heat gain/loss can be adjusted by metabolically inexpensive means
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What happens to an endotherm above and below the thermoneutral zone?
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their metabolic rates rise
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What are some metabolically inexpensive ways in which an endotherm might adjust heat gain or loss from its body
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fluffing of feathers or shivering or burning fat
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Why do ectotherms have high prod efficiences, are able to occupy hab with seasonal food supplies or little oxygen and are able to assume shapes and sizes with high surface area to volume ratios
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low-cost strategy
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how does ectothermy favor anerobic metabolism
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they use short, bursts of violent activity to help them escape from predators
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What are the disadvantages of ectothermy
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Dependent on external heat sources
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What are the adv and disadv of endothermy
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Adv. independence from external heat sources
-can live in high altitudes and can go out at night -can maintain high level activity by aerobic metabolism so can migrate long diff disadv: high energetic costs -little energy for reproduction -must care for young for long time |
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What is ecotypic variation and how is it important to the ecology of individuals
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diff pop of same species living in diff habitats differ in their response to temperature
-this is a way that genetic differences and acclimatization can be seen???? |
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What is bergmann's rule
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In animals having broad ranges, individuals from colder climates are often larger than members of the same species from warmer parts of their range
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What is allen's Rule?
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endothermic animals from cold climates have shorter extremities than animals with otherwise similar char in warmer climates
-ex: ears of kit fox in desserts and tundra |
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What is Glogers rule
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endotherms living in warm and humid areas are more heavily pigmented than those living in cool dry areas
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Life-zones would be applied to what type of habitat?
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mountains
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What is the normal dry adiabatic lapse rate
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1 degree C / 100 m
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What is an average moist adiabatic lapse rate
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Less (0.6 degrees C / 100 m)
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What is meant by an environmental lapse rate
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changes in temperature lapse rate that depends on the environment
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How does temperature influence the concentration of dissolved o2 in aquatic habitats
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as temperature increases, the solubilitiy of oxygen decreases
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What is thermal pollution and what are some of its possible consequences
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waters used for industrial cooling are being taken out of aquatic ecosystems
-restricts the types of organisms that can survive -relationships with compet. -susceptability to disease |
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What is acid precipitation and what are some of its possible consequences
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resulting from burning of fossil fuels
-can cause damage to lakes and coniferous forests |
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In what type of habitat are extreme saline conditions most likely?
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deserts
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explain why the moist adiabatic lapse rate is lower than the dry adiabatic lapse rate
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as air contains moisture, it cools
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What is albedo
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A measure of the percentage of incident solar radiation that is reflected back from the earths surface
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What are albedos for coniferous forests?
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as low as 5%
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What are albedos for deciduous forests
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30%
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What are albedos for deserts?
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50-60%
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what are albedos for ice and snow?
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90%
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What determines the albedo of hwater?
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very low (2%) for direct rays but high for low angle rays
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What factors influence the amount of solar radiation passing through the earth's atmosphere that actually reaches the Earths surface?
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clouds, dust, smoke, pollution
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Why do the sun's rays strike the Earth's surface at increasingly oblique angles toward the poles and what are the consequences?
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-because the earth is inclined on a 23.5 degree plane relative to the sun
-this means spots on higher latitudes recieve less energy cuz it has to go through a thicker layer of Earth's atmosphere -mean temps tend to decrease with incresing latitude (dist from eq) |
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What are some of the effects of the Earth's rotation on its polar axis on the biosphere?
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-daily cycles
-wind patterns -ocean currents, tides |
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Distinguish between the environment of a north-facing and south-facing slopes in La Crosse
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-north-facing slopes recieve the least amt of direct solar radition, cooler, have higher soil moisture, and lower rates of evap.
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Describe the climatic conditions encountered around the equator and explain why
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-sun heats most intensely in tropics
-warmed air picks up moisture and rises -creates low pressure area that drops rain |
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Where is the subpropical high-pressure area located, explain why and describe the conditions encountered here
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-located around 30Degrees N-S
-as air descends, it is heated and dried -creates deserts |
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Where is the subpolar low-pressure area located, explain why and describe the conditions encountered here
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-rest of air from eq continues to go towards the poles to rise again with air coming down from the poles at 60 degrees N-S lat.
-has precipitiion |
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What types of conditions are located in the region known as the polar high-pressure area
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-little precipititation
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What is the coriolis force and what causes it?
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-the deflection of wind patterns from movement of air from high to low pressure areas
-patterns are caused by rotation of the earth |
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In what direction does the Coriolis force in the Northern hemisphere deflect air masses moving in a north-south direction?
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right
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In what direction does the Coriolis force in the Southern hemisphere deflect air masses moving in a north-south direction?
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left
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What happens to air returning from the subtropical highs to the equatorial lows in the northern and southern hemispheres?
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-deflected to the right causing northeast trade winds
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WWhat happens to the air flowing toward the subpolar lows in the middle latitiudes
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gives rise to prevailing westerlies
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What is meant by a "west wind"?
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The wind blew FROM the west
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In what directions will the prevailing winds blow FROM on an island located in the Caribbean Sea?
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East
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In what direction will the prevailing winds blow toward on an island located in the Caribbean Sea?
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West
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How might sunlight act as an environmental condition?
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It is a stimulus for timing of daily and seasonal rhythums
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What are the approximate wavelenths of photosyntheically active radiation (PAR)
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400-700 nm
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Contrast the arrangement of leaves on trees growing in open areas with those growing in dense shade? why?
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In the open: broken multilayer to expose max leaf area to lowered light intensity where photosyn most efficient
-Dense shade: arranged with little overlap to intercept all incoming light directly |
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How does total leaf area of trees growing in the open compare with trees growing in shade?
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-open: total leaf area will be larger than ground area
-shade: total leaf area=ground area |
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How does the leaves on trees growing in the open differ from those growing in the shade
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-open: smaller and of irregular shape to permit light to diffuse down to lower layers
-shade: larger and regular shaped |
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Distinguish between sun leaves and shade leaves
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-Sun Leaves: smaller, thicker, have more cells and chloroplasts per unit area and denser veins
-shade leave: larger area relative to dry weight, often more transperant and don't have much photosyn activity |
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Where would plants with inclined leaves most likely be found
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prairies and drier regions where trees can't grow
-grasses |
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What is evapotranspiration and what causes it?
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water loss through evaporation and transpiration (water loss from plant parts to air?)
-if stomates are open, water will evaporate through them |
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What are the strategies used by plants for controlling water loss while carrying out photosynthesis?
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-control stomatal openings in a way that keeps plant watertight except when photosynthesizing
-produce leaves that transpire slowly and tolerate water deficit -may shed leaves in drought -hairs, sunken stomates, low stomates that prevent water loss -reflective surfaces or waxy cuticles |
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What is the role of RuBP carboxylase in C3 plants?
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enzyme passes Co2 to calvin-benson cycle
-some of carbon held is oxidized in photorespiration and vented back as CO2 |
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What is photorespiration and under what conditions does it occur?
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when some of carbon is held by RUBP Carboxylase and is oxidized to be vented back as co2
-happens in presence of light and free o2 |
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Describe what happens to CO2 in C4 plants (grasses)
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the Co2 is collected from air spaces inside stomates by PEP carboxylase
-passes it to a series of 4-carbon acids which are transported to the chloroplast cells -Co2 regenerated |
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Under what conditions do C4 plants have an advantage of C3 plants and why?
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Hot, dry places with little water but not as efficient at lower temp and light
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Under what conditions do CAM plants have an advantage over C3 plants
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Stomates open at night
-well adapted to hot dry climates but don't do well in other habitats |
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What is field capacity?
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The amount of water held by soil pores against the force of gravity
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What is the permanent wilting point of soils and how is this important?
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Lower limit of water-holding capacity
-determined by the ability of plants to exert sufficient suction to force water from smaller pores -at this point, plants will wilt and can't recover |
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Distinguish between tap roots and branching roots
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taproots: go deep to capture underground water
Branching roots: quickly absorb surface runoff |
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Explain how roots may be explorers
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the elongate before they produce lateral extensions
-exploration precedes exploitation |
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Explain how roots may be opportunists
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as they pass through soil, they produce lateral branches in zones that supply resources and no branches in less rewarding patches
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In what ways do terrestrial animals differ in their abilities to conserve and utilize water
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-permeability of their skin
-types of kidneys they have or tyhpes of waste molecules they produce -ways they get water (metabolism, drinking, food) |
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What is the relationship between the solubility of oxygen in water and water temperature
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Solubility of oxygen in water decreases with increasing temperature
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What problems might animals experience from thermal pollution and why?
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metabolic rates increase with temperature
-oxygen may be limiting in warmer waters |
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Deistinguish between macronutrients and trace elements in the soil and give examples of each
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Macronutrients: needed in large amounts: N, phosphorus, K Ca, mg, Fe
Trace elements: mg zinc copper -can be limiting |
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what is meant by the term "biosphere"
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the portion of the earth where life exists
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Define stenotopic
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organisms with narrow ranges of environmental tolerance
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What is Eurytopic
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Organisms with broad ranges of environmental tolerance
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What are proximate and ultimate factors
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proximate: immediate cues that organisms use to select habitat
-ex: temp, moisture, water Ultimate: selection pressures that genetically determine |
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What are 3 reasons an organism might not be found in a given habitat
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-habitat is unsuitable to requirements
-organism can't get there -biotic interactions (comp, pred, disease, etc) |
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what is biogeography
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distribution of organisms and reasons for observed patterns of distribution
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What is Liebig's law of the minimum and how it influences the dev of the modern niche concept
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populations may be limited by the single, necessary resource having the greatest scarcity
-deals with limiting resources and competition |
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What is shelfords law of tolerance and how does it influence the dev of the modern niche concept
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for each environmental factor, their must be a range of values
-if animals have wide range of tolerance, they will live in a wider range of habitats |
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What is ecological niche as stated by hutchinson in his hypervolume model
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an n-dimentaional hypervolume with complete range of condition in which an organism can survive and reproduce
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distinguish between the fundamental and realized niche?
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--fundamental: hypothetical idealized niche in which the organism encounters optimal conditions
--realized niche: actual set of conditions in which an organism lives |
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give 3 problems with the concept of the ecological niche as defined by hutchinson
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1. there are an infinite number of dimentions
2. the model assumes variables can be linearly ordered and measured which would be hard for living (biotic) dimensions 3. the model is for a single instant in time when things are ever changing |
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What way did MacArthur suggest ecologists might escape some of the problems with hutchinsons model when investigating the ecological niche of an organism
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restrict discussion to diff between niches in one or two clearly important dimensions
-ex: feeding niches of 2 closely related birds -avoid ones that are of little imp. |
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State the competitive exclusion principle
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no two organisms with exactly the same ecological requirements living in the same habitat should be able to occupy the same ecological niche.
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What is niche breadth?
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amplitude of ecological conditions utilized by individual species
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What is niche overlap?
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Occurs when two organisms use the same resources or environmental variables
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