Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
122 Cards in this Set
- Front
- Back
|
Ecology |
experimental analysis of the distribution and abundance of organisms Natural history is the pattern; Ecology is the pattern+process |
|
|
6 Levels of ecological investigation |
1. Individual: physiological ecology 2. Population: evolution, population growth, fluctuation, and regulation, demography, life history strategies 3. Species: competition, herbivory, predation and parasitoidism, mutualism 4. Community: succession, diversity 5. Ecosystem: productivity, energy flow, nutrient cycling 6. Global: biodiversity loss, ecological consequences, climate change |
|
|
Physiological ecology |
what traits allow organisms to deal with the abiotic (physical) and biotic stresses of their environments |
|
|
Fundamental niche |
potential range; all of the habitats in which a species could live and reproduce determined by physiological tolerances to abiotic factors such as light, temperature, moisture, nutrients, etc. |
|
|
Realized niche |
actual range - all of the habitats in which a species does live and reproduce determined by abiotic and biotic factors (disease, competition, herbivory, predation, lack of dispersal, etc) |
|
|
Temperature |
1. Latitudinal variation in temperature due to variation in solar radiation as a result of the spherical shape of earth and tilt of axis. Gradient is attenuated by oceanic circulation which moves heat from equator toward poles. Example: Temperature limits distribution of coral reefs to between 30 N and S latitude because coral reef organisms cannot make calcium carbonate below 20C. |
|
|
El nino |
winds push warm surface water to west Pacific, warm surface water then flows east through pacific, warming Western North and South America |
|
|
Altitude |
Local variation in temperature. 3.5F decrease in temperature per 1000 ft. Forms predictable communities with gradient. Example: Dry forest=>Wet Forest=>Cloud Forest=>Elfin Forest=>Grass |
|
|
Slope faces |
Local variation in temperature Slope facing equator will be hotter. In Michigan, south facing slopes are hotter and drier and are populated by aspen and birch while north facing slopes are cooler and wetter and populated by hemlock |
|
|
Height above ground |
Local variation in temperatre At ground, light's conversion into heat happens and results in temperatures as much as 25dF higher than at 4 ft from ground. Example: Can affect seedling survival of trees |
|
|
Seasonal variation |
Temporal variation in temperature. due to Earth's tilt and orbit. |
|
|
Lake effect |
Land cools and heats faster than water. Water from the west moves air across a lake, which warms up and can hold more moisture. The air then cools and precipitates as air moves across the land. For lake effect to occur, air must pass over water then land. Fall is the time of greatest lake effect. Once lake is iced over, then the lake effect is done. |
|
|
Diurnal variation |
Night vs day temperatures Thermal inertia of large bodies of waters make coasts experience least variation. Deserts and mountains experience most variation Variation is greatest at the ground |
|
|
Onshore/offshore breezes |
Onshore breezes occur during the day when warm air on land rises and creates a vacuum which pulls in air from over water. Offshore breezes occur at night when warm air rises off of the water and pulls air from land |
|
|
Homeothermy |
maintaining a constant body temperature Most are also endotherms birds and mammals Approx. 15,000 species |
|
|
Poikilotherms |
body temperature varies with environmental temperature Most are also ectotherms 99% of animals 15,000,000 species |
|
|
endotherm |
generates heat from within |
|
|
ectotherm |
body heat is obtained from the environment |
|
|
Homeotherm adaptations |
1. insulation - fur and feathers from reptile scales (keratin) trap air close to body to prevent heat loss to environment 2. Manipulation of boundary layer - increasing thickness of still air above skin to become thicker in cool temps. Goose bumps, puffing up feathers 3. Increased activity - shivering, contracting muscles to produce heat 4. Decreased activity - hibernation, torpor 5. brown adipose tissue - fat with many capillaries, produces heat instead of ATP 6. Altered SA/V ratio - Bergman's and allen's rules. 7. Countercurrent exchange - heat transfer from arteries to veins. Present in aquatic verts and birds 8. partial or temporary poikilothermy - some tissues able to drop temperature and others stay warm. ex. Tuna. Hibernation and torpor 9. migration - running away from cold weather. Hard in eastern hemi because of Sahara desert. 10. Evaporative cooling - using body heat to convert liquid water to vapor. AKA sweating, panting. |
|
|
hibernation |
Mammals body temperature drops by up to 60dF energy use drops by up to 95% prepare by accumulating fat |
|
|
torpor |
short term (overnight) decrease in body temperature body temp drops by 20-45dF energy use drops by 90& mostly in endotherms with high SA/V such as small birds and bats |
|
|
Brown adipose tissue |
Fat with many capillaries oxidation is decoupled from phosphorylation, so the fat produces heat instead of ATP primarily used to resume activity bears, bats, hummingbirds, infant humans |
|
|
Bergman's rule |
Body size increases with latitude example: ermines are larger further north |
|
|
cline |
gradual change in a trait over a distance |
|
|
Allen's rule |
appendage length decreases with latitude ex. arctic hare |
|
|
Poikilotherm adaptations |
1. Behavioral regulation - heliothermy - using the sun to warm (basking) 2. Decreased activity - diapause in insects (long term inactivity); hibernation in some amphibians and reptiles 3. Freeze tolerance - liver glycogen is turned to cellular glucose so that only extracellular water freezes 4. isozymes - multiple copies of the same enzyme encoded by different genes with different temperature optima, which allows temperature acclimation |
|
|
Diapause |
long term inactivity in insects as a response to cool temperatures - synthesize ethylene glycol in response to shorter days - energy use drops by >99% - termination in response to warmer temperatures Very susceptible to late freeze once they come out of diapause, or coming out of diapause due to very early warming followed by normal cool |
|
|
Traits of poikilotherms affected by temperature |
1. Development rate - cabbage butterfly - increased temp = increased rate of growth 2. Activity - cold temps make bodies function more slowly 3. awareness - pit vipers? 4. environmental sex determination - in some reptiles, offspring sex is determined by egg incubation temps 5. geographic range - range determined by acceptable temps |
|
|
Sulfur butterflies, 1992 |
Mt. Pinotubo eruption made global temps cooler White, "alba" mutant develops faster than yellow ones, so metamorphosis can occur faster => able to do better in shorter growing season Nitrogen is used for growth instead of making pigment. Only females are alba because they are heterogametic (XO) |
|
|
isotherm |
line on a map connecting points of equal temperature |
|
|
Hadley cells |
Air warmed up at equator picks up lots of moisture, rises, and rains a bunch. Tropical rainforests Cool dry air descends at around 30dN and S and absorbs moisture to make a desert. |
|
|
tropopause |
acts like ceiling for atmosphere |
|
|
Rain shadow |
Moist air from body of water is pushed up by mountain range, condenses and precipitates to make the air very dry. Descending dry air makes a cool desert. |
|
|
Wind patterns |
Westerlies from 30 to 60 d. air flows east becase hadley cell is forcing air north ane spin of earth makes the wind move faster west relatively northeast tradewinds move southwest because the air is moving south and must speed up as it moves to equator |
|
|
Rainy vs dry seasons |
Hadley cells shift position through year to make dry and wet seasons at 20dNandS |
|
|
Adaptations to moisture stress |
1. Desiccation tolerance - dry out but don't let it kill you - mosses 2. Desiccation avoidance - plant structure with waxy cuticle, xylem, and stomata prevent leaf from drying; succulence, CAM photosynthesis Chitin exoskeleton in insects Uric acid for nitrogenous waste Nocturnal lifestlye Migration |
|
|
CAM photosynthesis |
CO2 levels build up over the night in the air Stomata open during night to let in CO2 and close durnig the day to keep in moisture Attach CO2 to organic acid and continually pull in more CO2 Used for photosynthesis during day |
|
|
Uric acid |
Used instead of ammonia or urea to expel nitrogenous waste crystalline and excretion requires almost water to expel Is relatively non toxis Developed in hard shelled eggs so that the developing embryo could deal with waste without expulsion |
|
|
Factors affecting distribution of organisms |
Temperature Moisture Light |
|
|
Light |
Varies globally Locally in availability at ground level (understory) Temporally |
|
|
Evolutionary responses to variation in light |
1. light response curves describe how net photosynthesis responds to light intensity Light compensation point - minimum amount of light the plant needs to survive Light saturation point - maximum amount of light the plant can use for photosynthesis Sun and shade leaves - phenotypic plasticity - high light leaves have more chloroplasts and are thicker Accessory pigments absorb wavelengths that chlorophyll misses |
|
|
Biosphere |
zone of life on earth Most organisms occur within 200 m of Earth's surface |
|
|
Microevolution |
change in allele frequency within a population Genetic variation is necessary and sufficient for microevolution to happen |
|
|
Macroevolution |
origin of a new species, genera, etc arises from accumulated microevolutionary traits |
|
|
4 Mechanisms of Microevolution |
1. mutation (very slow) 2. Natural selection (causes adaptive evolution) 3. Genetic drift (chance; causes nonadaptive evolution) 4. Immigration, emigration |
|
|
Natural selection |
differential reproduction among genotypes within a population |
|
|
Fitness |
a genotype's rate of reproduction relative to other genotypes in the same population -higher fitness genotypes leave more offspring, so their alleles increase in the population best measured as genotype's relative rate of reproduction(realized r) |
|
|
Directional selection |
one extreme phenotype has highest fitness mean phenotype shifts toward favored extreme pepper moth color in industrial England |
|
|
Stabilizing selection |
intermediates have highest fitness same average but reduced variation firefly flashes and femme fatale syndrome |
|
|
Disruptive selection |
both extremes have highest fitness same average, increased variation eventual result is two species pollination in monkey flower - 2 different colors attract insects and hummingbirds rare because once it starts, 2 separate species come about |
|
|
Individual selection |
traits increase because they are good for the individual -explains most adaptations |
|
|
Group selection |
traits increase because they are good for the group, even though they may be bad for the individual best examples are altruistic behaviors within kin groups which are favored through kin selection |
|
|
Species selection |
traits increase because they are good for the species in the long run, even though they may be bad for the individual in the short run Species with higher mutation rates may go extinct more slowly, especially if environments change fast enough, even though most mutations are bad for the individual |
|
|
2 common misconceptions about natural selection |
1. Nat selection typically favors traits "for the good the population" or "for the good of the species" but the prudent predator fallacy illustrates why that won't work 2. natural selection is omnipotent a. the optimal mutation may never have arisen b. if it did arise, drift almost certainly eliminated the mutation before selection could make it increase c. selection has to choose among packages of effects, which may include maladaptive traits that hitchhike with adaptive traits d. traits often (usually) get trapped at suboptimal states (local optimum rather than global optimum) e. even if selection achieves global optimum, the adaptive landscape will change |
|
|
Genetic drift |
strongest force acting on small populations change in allele frequencies due to chance causes nonadaptive evolution drift acts on all love with more than 2 alleles, including neutral loci |
|
|
Two main consequences of genetic drift |
1. loss of alleles from population, especially rare alleles, including mutations 2. genetic divergence between populations, due to loss of different alleles from each population Both happen faster if population is small Pop ends up "fixed" for one of the alleles |
|
|
Small populations affected by genetic drift |
all threatened species island species (inc. alpine, fragment, freshwater) peripheral populations populations that experience bottlenecks - temporary, sever reductions in population size (cheetahs, elephant seals) |
|
|
Population |
a group of individuals of the smae species that live in the same area and breed exclusively or primarily with eachother. |
|
|
Population growth |
Determined by total births, deaths, immigration and emigration |
|
|
dN/dt |
rate of population growth (individuals/time) can be positive or negative =N*realized r |
|
|
N |
population size (N) |
|
|
realized r |
current average per capita net rate of reproduction (individuals/individual/time) =b-d =(per capita birth rate - per capita death rate) can be positive or negative |
|
|
rmax |
a special case of realized r; the maximum per capita net rate of reproduction the environment allows, assuming unlimited access to local resources |
|
|
Exponential growth |
dN/dt = N(rmax) realized r is always rmax per capita reproductive rate is density-independent small changes in rmax have huge effects on population growth, so natural selection will strongly favor traits that increase individual reproductive rate |
|
|
Logistic population growth |
dN/dt = N*rmax*(K-N)/K K = carrying capacity (K-N)/K = crowding factor that makes growth density dependent rmax*(K-N)/K = realized r = per capita reproductive rate (changes with N) |
|
|
Carrying capacity |
K = the maximum number of individuals the environment can sustain indefinitely |
|
|
point of maximum sustainable yield |
in logistic growth, where dN/dt is maximized K/2 |
|
|
Assumptions of logistic growth model |
1. all individuals in population have same effect on net reproduction and crowding Demography addresses 2. realized r decreases linearly as N increases. Mate finding is a problem with small pops, and inbreeding occurs 3. realized r is determined by current population size doesn't take reproductive lag or gestation into account 4. K is constant for a given habitat |
|
|
Minimum critical population size (allee effect) |
the number of individuals where realized r is equal to 0. if the number of individuals drops below this, the species falls into the extinction vortex. |
|
|
Population fluctuation |
Bust and boom fluctuation is the rule, not the exception population crashes are most often due to weather events |
|
|
Population regulation |
effective density-dependent population control must cause realized r to go down enough to keep population the same requires that, as N increases, realized r must decrease to 0 or below due to decrease in reproduction in reproduction and/or increase in mortality |
|
|
Population regulation factors |
1. competition - more competition => fewer resources for each => fewer offspring more competition => less healthy individuals => higher mortality 2. dispersal - some species show density dependent dispersal, such as locusts 3. predation - predator switches to prey on one population => mortality increase in more abundant population => mortality decrease in other population present => boom, and switch to more abundant 4. parasitoids - can cause density - dependent mortality. % caterpillars dead increases as caterpillar population increases 5. disease - cause density dependent mortality due to less strong individuals and easier spread in large groups |
|
|
Population cycles |
A. could be due to cyclic environmental factor, but not shown in nature. Predator prey cycles questionable. |
|
|
Demography |
the study of age specific patterns of survivorship and reproduction within a population 1. Divide population into age classes 2. Describe averages for each age class 3. generate population patterns |
|
|
x |
age class (year, month, etc) |
|
|
nx |
number of individuals alive at the start of age class x |
|
|
dx |
number of individuals dying during age class x |
|
|
lx |
survivorship = proportion of individuals surviving from birth to the start of age class x |
|
|
ex |
life expectancy = the average number of age classes yet to be lived by an individual at the start of age class x |
|
|
Type I survivorship curve |
"large mammal curve" significant parental care does not guarantee high survivorship few, large offspring |
|
|
Type 2 survivorship curve |
rare constant chance of death throughout lifespan |
|
|
Type 3 survivorship curve |
many, small offspring high mortality in beginning no parental care offspring usually are orphans at birth >>99% of all species |
|
|
mx |
fecundity = average number of daughters born during age class x to a female who survived to age class x |
|
|
lxmx |
realized fecundity = average number of daughters a newborn female will produce during age class x average of survivors and non survivors |
|
|
Ro |
net replacement rate = average number of daughters produced over a female's lifetime = sum(lxmx) when Ro > 1, pop is growing |
|
|
semelparity |
reproducing once |
|
|
iteroparity |
reproducing more than once |
|
|
senescence |
body breaks down selection against senescence is very weak because reproduction in later age classes adds very little to fitness |
|
|
Life history tradeoff forms |
1. Current reproduction can decrease growth, eg isopods 2. Current reproduction can decrease survival, eg white-tailed deer 3. Current reproduction can reduce future reproduction |
|
|
antagonistic pleiotropy |
an allele has a beneficial effect on one trait and a deleterious effect on another eg. an allele may increase fecundity in early age classes but decrease survivorship at later ages natural selection favors the best overall package |
|
|
Scenario for population |
1. Most plant and animal populations in nature fluctuate wildly 2. wild fluctuations due to weather, predators, disease 3. repeated periods of exponential growth 4. selection for early reproduction 5. dominance of annuals on Earth |
|
|
r-selected species |
Rapid development, high reproductive rate, early reproductive age, small body size, short length of life, weak competitive ability, high mortality of young, variable population size, good dispersal, low parental care type 3 survivorship |
|
|
k-selected species |
slow development low reproductive rate late reproductive age large body size long life length strong competitive ability low mortality of young fairly constant population size poor dispersal ability high parental care type 1 survivorship |
|
|
Competition |
the use of a shared, limiting resource by two or more individuals |
|
|
limiting resource |
one whose abundance limits fitness |
|
|
scramble competition |
no defense of resources, just trying to be the first to the resource plants with light more common by far |
|
|
interference competition |
active defense of resources to prevent access by others (territoriality) rare among animals, but still much more common than in plants. eg lions steal cheetah's food |
|
|
Intraspecific competition |
within species - more common than interspecific competition because two members of the same species are more likely to share a resource crowding factor = (N-K)/K |
|
|
4 main consequences of competition |
A. hyperdispersion of competitors - more spaced out than expected at random. Either clumped/patchy or regular/even B. reduction in number, size, growth, or reproduction in the presence of the competitor C. Competitive exclusion - two species that use the same limiting resource cannot coexist D. Evolutionary responses to minimize competition, including Resource partitioning and character displacement |
|
|
Last glacial maximum |
21,000 years ago, average temperature was only 4-7dC cooler than today. Glaciers covered 30% of surface |
|
|
terminal moraine |
the hill formed at the furthest leading edge of a glacier; consists of unsorted material (till) |
|
|
recessional moraine |
a moraine formed at a point where a retreating glacier temporarily stops retreating; also consists of till |
|
|
outwash plain |
flat area immediately downstream of a moraine where glacial runoff in meltwater streams has deposited larger particles (sand and gravel) carried from the moraine |
|
|
kettle lake |
a small, round, deep lake formed by the melting of an ice chunk left behind by a retreating glacier; becomes a bog if invaded by sphagnum moss first. |
|
|
Hypothetico-Deductive Cycle |
1. observe nature 2. form hypothesis 3. generate predictions from hypotheses 4. test prediction a. state the null hypothesis b. design experiment c. conduct experiment d. perform statistical analysis e. interpret statistical analysis f. return to (A) or (B) |
|
|
Common mistakes in Experimental Design |
A. Failure to consider alternate hypotheses due to perceptual limitations B. Failure to consider alternate hypotheses due to advocacy science C. Failure to eliminate confounding vvariables D. Failure to eliminate noisy variables E. Failure to use the most appropriate statistical question F. failure to interpret results correctly |
|
|
Type I error |
rejecting a true null hypothesis |
|
|
Type II error |
accepting a false null hypothesis |
|
|
p-value |
probability that the null hypothesis is true, given the results you observed |
|
|
alpha |
the p-value required to reject a null hypothesis |
|
|
Chi square |
difference among distributions (ie relative abundance) |
|
|
t-test |
difference among means if distributions are normal |
|
|
Mann-Whitney U test |
difference among means if distributions are not normal |
|
|
ANOVA |
difference among more than 2 means |
|
|
F-test |
difference among variances |
|
|
regression |
association between two variable |
|
|
allelopathy |
plant secretion of toxic chemicals into the soil ex. sagebrush |
|
|
Competitive exclusion |
two species that use the same resource cannot coexist ex. paramecium species competitively exclude |
|
|
Resource partitioning |
evolutionary response to minimize competition in which: sympatric species use a limited resource in different ways, presumably due to past selction for avoidance of competition eg. Anolis lizards bask in different parts of the same tree |
|
|
character displacement |
evolutionary response to competition which is: divergence of a character in one or both species where they co-occur, presumably due to past interspecific competition leads to less resource overlap in sympatry than in allopatry eg. beak sizes in Darwin's finches |
|
|
allopatric |
living in different areas |
|
|
sympatric |
living in the same area |
