Ecology Flashcards

Question

tropical forest

Answer 1

rainfall is relatively constant, about 200-400 cm annually in tropical rainforests tropical dry forest - precipitation is highly season temperature is high year round with little seasonal variation tropical forest vegetation is usually vertically layered with intense competition for light highest biodiversity of any terrestrial biome

Answer 2

occur in bands near 30 degrees north and south latitude or at other latitudes in the interior of continents temperature is variable seasonally and daily, can be very high or very low dominated by low widely scattered vegetation, many plants do CAM photosynthesis

Answer 3

occurs in equatorial and subequatorial regions dry season can last up to eight or nine months warm year-round, but with more seasonal variation than tropical forests scattered trees are thorny with small leaves; fires are common in the dry season grasses and forbs make up most of the ground cover, most animals are large and plant-eating or predators

Answer 4

occurs in midlatitude coastal regions on several continents and is widely distributed fall, winter, and spring are cool and summer is warm dominated by

Answer 5

eg plains and prairies of central North America precipitation is often highly seasonal with relatively dry winters and wet summers; periodic drought is common winters are generally cold while summers are hot dominant plants are grasses and forbs, many grasses have adaptations to help survive drought native mammals include large grazers like bison and wild horses

Answer 6

largest terrestrial biome on Earth, extending in a broad band across N America and Eurasia to the edge of the arctic tundra precipitation varies winters are usually cold and summer may be hot dominated by cone-bearing trees, such as pine, spruce; conical shape of conifers prevents too much snow from accumulating and breaking their branches lots of migratory birds

Answer 7

found mainly at midlatitudes in the Northern Hemisphere precipitation highest in fall, sometimes winter snow cold winters, hot and humid summers mature TBF has distinct vertical layers, including a closed canopy dominant plants are deciduous trees, which drop their leaves before winter when low temps would reduce photosynthesis many mammals hibernate in winter

Answer 8

covers expansive areas of the Arctic and alpine tundra on very high mountaintops low precipitation winters are very cold, summers also cold vegetation is mostly herbaceous - mosses, grasses, forbs; permanently frozen layer of soil called permafrost restricts the growth of plant roots large grazing species and predators

Answer 9

make up the largest marine biome, covering about 75% of Earth's surface water evaporated from the oceans provides most of the planet's rainfall ocean temperatures have a major effect on global climate and wind patterns (aquatic biomes are classified by marine or freshwater)

Answer 10

formed largely from the calcium carbonate skeletons of corals shallow reef-building corals live in the photic zone of relatively stable tropical marine environments with high water clarity require high oxygen levels and a solid substrate for attachment corals are main organisms, but overall biodiversity is very high

Answer 11

periodically submerged and exposed by the tides, wice daily on most marine shores upper zones experience longer exposure to air and greater variations in temperature and salinity oxygen and nutrient levels are generally high and renewed with each turn of the tides high diversity and biomass of attached marine algae many heterotrophs

Answer 12

transition area between river and sea; seawater flows up the estuary channel during a rising tide and flows back down during the falling tide salinity varies within estuaries, from fresh water to seawater nutrients from the river make estuaries very productive biomes complex networks of tidal channels, islands, etc saltmarsh grasses and algae

Answer 13

most prominent physical characteristic is speed and volume of flow river - water generally warmer and more turbid than streams salt and nutrient content increases from oxygen-rich headwaters to the mouth headwater streams may be rich in phytoplankton or rooted aquatic plants, also a great diversity of fishes and invertebrates

Answer 14

standing body of water covering large areas oligotrophic - nutrient poor and generally oxygen rich eutrophic - nutrient rich and often depleted of oxygen in the deepest zone, covered with ice in winter littoral zone - shallow, well-lit waters close to shore limnetic zone - far from shore, too deep to support rooted aquatic plants, but has phytoplankton and drifting heterotrophs

Answer 15

habitat inundated by water at least some of the time and that supports plants adapted to water-saturated soil both water and soils are periodically low in dissolved oxygen basin wetlands - develop in shallow basins riverine wetlands - developing along river and stream banks water-saturated soils favor the growth of plants

Answer 16

many aquatic biomes are physically and chemically stratified photic, aphotic make up pelagic benthic abyssal

Answer 17

photic zone - upper part of pelagic zone, where there is sufficient light for photosynthesis aphotic zone - lower zone where little light penetrates

Answer 18

pelagic zone - made up of photic and aphotic zone, above benthic and abyssal zone benthic zone - bottom of all auatic zones, deep or shallow; made up of sand and organic and inorganic sediments, occupied by communities of organisms collectively called the benthos major source of food for benthic species is detritus

Answer 19

part of the ocean 2000-6000 m below the surface | deep in the aphotic zone

Answer 20

"surface" of land in aquatic biomes

Answer 21

dark, hot environments where food producers are chemoautotrophic prokaryotes located on mid-ocean ridges, deep sea marine benthic zone

Answer 22

narrow layer of abrupt temperature change that separates the uniformly warm upper layer of a lake/ocean from the more uniformly cold deeper waters lakes tend to be especially layered except for turnover in temperate lakes

Answer 23

temperate lakes undergo a semiannual mixing of their waters as a result of changing temperature profiles sends oxygenated water from a lake's surface to the bottom and brings nutrient-rich water from the bottom to the surface in both spring and autumn

Answer 24

plate tectonics have enabled us to figure out the history of the continents continental drift has changed the makeup and nature of organisms on continents, which had to move or adapt or go extinct

Answer 25

Wallace recognized that different places on Earth had different sets of organisms, he called these biogeographic regions only recently did we associate that with plate tectonics

Answer 26

occurs when continents come together eg we got marsupials in N America from S America when the continents came together, and S America got bears etc from here

Answer 27

occurs when the range of a species or lineage is split apart

Answer 28

immigration - influx of new individuals from other areas | emigration - movement of individuals out of a population and into other locations

Answer 29

how widespread a species is | eg Devil's hole pupfish has a very small range, while humpback whale has a very large range

Answer 30

amount of time taken for a cohort to go from birth to when all the individuals are dead

Answer 31

ratio of male to female

Answer 32

describes population growth in an idealized, unlimited environment you know what exponential growth is why'd you even make this dumbass flashcard

Answer 33

defense of a bounded physical space against encroachment by other individuals often results in uniform patterns of dispersion

Answer 34

clumped dispersion habitats are patchy even on a small scale organisms are not distributed randomly in space help prevent extinction because even if one patch undergoes a disturbance, the species is distributed in other patches as well

Answer 35

set of patches vary over time in whether they're occupied or not

Answer 36

``` B = births D = deaths Nt+1 = Nt + B - D ∆N/∆t = B - D ignores immigration and emigration (for now) ```

Answer 37

``` b = per capita birth rate (fecundity) m = per capita death rate (mortality) r = per capita rate of increase r = b - m r = 0, zero population growth (ZPG) ∆N/∆t = rN rinst = instantaneous, intrinsic or innate dN/dt = rinstN, a maximum rate of increase ```

Answer 38

fertility - TFR total fertility rate is the expected number of children born per woman in her child-bearing years fecundity - average number of young per female of age x

Answer 39

fertility schedule - age-specific summary of the reproductive rates in a population constructed by measuring the reproductive output of a cohort from birth until death tallies the number of female offspring produced by each age-group for sexual species

Answer 40

randomly selected group of individuals of the same age

Answer 41

Type I - flat at the start, reflecting low death rates during early and middle life, and then drops steeply as death rates increase among older age groups (examples are many large mammals including humans) - inverted L, opposite of type III Type II - intermediate, with constant death rate over the organism's life span (occurs in squirrels, rodents, plants, etc.) looks like a downward slope like my GPA Type III - looks like an L which is what I'll be taking on this midterm, drops sharply at the start reflecting very high death rates for those few individuals that survive the early period of die-off

Answer 42

the stages that an organism goes through in its life, not to be confused with life table etc

Answer 43

maximum number of organisms supported by a particular environment and its resources

Answer 44

per capita rate of increase approaches zero as the population size nears the carrying capacity

Answer 45

repeated reproduction eg female loggerhead turtles produce four times in a year organisms tend to produce relatively few but large offspring each time they reproduce, and they provide for the offspring better favored in more dependable environments, where adults are more likely to survive to breed again and where competition for resources may be intense

Answer 46

density-independent selection selection for traits that maximize reproductive success in uncrowded environments (low densities) said to maximize r, the per capita rate of increase and occurs in environments in which population densities are well such conditions are often found in disturbed habitats

Answer 47

principle of allocation - only have so much food, resources, energy etc that can be allocated into survivorship or reproduction etc (not conscious decisions, but if energy is available it is possible to invest more into a wider range of activities) trade offs: reproduction or survival

Answer 48

how resources are divided entails 3 main variables: when reproduction begins (the age at first reproduction or at first maturity) how often the organism reproduces how many offspring are produced per reproductive episode

Answer 49

density-dependent selection selection for traits that are sensitive to population density and are favored at high densities said to operate in populations living at a density near the limit imposed by their resources (the carrying capacity) when competition among individuals is stronger

Answer 50

birth rate or death rate does not change with population density examples - mortality of grass due to physical factors that kill same proportion of a local population regardless of density, ilke drought stress

Answer 51

death rate that increases with population density or a birth rate that falls with rising density eg scarcity of water or nutrients with more organisms key factors regarding birth rate are density dependent, while death rate is largely regulated by density-dependent factors

Answer 52

combination of density-dependent and density-independent factors can stop population growth, resulting in equilibrium population density

Answer 53

individuals may have a more difficult time surviving or reproducing if the population size is too small for example, a single plant may be damaged by excessive wind if it is standing alone, but it would be protected by a clump of individuals

Answer 54

minimal population size at which a species is able to sustain its numbers

Answer 55

total population size may be misleading because only certain members of the population breed successfully and pass on traits effective population size is based on the breeding potential of the population, incorporates sex ratio

Answer 56

incorporates immigration and emigration as well as births and deaths

Answer 57

if a subpopulation in a metapopulation disappears, it can be rescued by organisms moving to that path or by researchers moving organisms to a patch to rescue it

Answer 58

mechanism to increase connectivity between populations so that the organisms can move from one habitat to another management strategy, example of conservation biology

Answer 59

include competition, predation, herbivory, symbiosis, and facilitation interactions with other individuals of the other species in the community

Answer 60

a -/- interaction that occurs when individuals of different species compete for a resource that limits their growth and survival

Answer 61

predation - +/- in which one species kills and eats the other herbivory - +/- interaction in which an organism eats parts of a plant or alga parasitism - +/- in which one organism derives its nourishment from another organism, which is harmed in the process pathogen interactions - +/- probably

Answer 62

(+/+) - interspecific interaction that benefits both species eg nitrogen fixation by bacteria in the root nodules of legumes, nutrient exchange between fungi and plant roots obligate mutualism - one species cannot survive on its own facultative mutualism - both species can survive on their own

Answer 63

(+/0) - interaction between species that benefits one of the species but neither harms nor helps the other

Answer 64

species can have positive effects on the survival and reproduction of other species without necessarily living in the direct and intimate contact of a symbiosis particularly common in plant ecology

Answer 65

when individuals of 2 or more species live in direct and intimate contact with one another - all such interactions, whether they are harmful or not

Answer 66

sum of a species' use of the biotic and abiotic resources in its environment

Answer 67

niche potentially occupied by a species identified by testing the range of conditions in which a species grows and reproduces in the absence of competitors

Answer 68

portion of the fundamental niche that an organism actually occupies

Answer 69

two species competing for the same limiting resources cannot coexist permanently in the same place; in the absence of disturbance, one species will use the resources more efficiently and reproduce more rapidly than the other even a slight reproductive advantage will eventually lead to local elimination of the inferior competitor Gause - noted this phenomenon in paramecium experiment

Answer 70

differentiation of niches that enables similar species to coexist in a community eg using different resources or using the same resources at different times of day or the year

Answer 71

disease-causing microorganisms, viruses, viroids, or prions | produce especially clear effects when introduced into a new habitat, important in clear effects

Answer 72

pathogens that are transferred to humans from other animals, either through direct contact with an infected animal or by means of an intermediate species

Answer 73

species tend to do better when they are rare (while they remain rare) will not have to face as much competition from other species or from other members of their own species

Answer 74

``` extension of logistic equations predator and prey dN1/dt = r1N1(K1-N1-aN2)/K1 dN2/dt = r2N2 (K2-N2+BN1)/K2 species 1 is prey, species 2 is predator because 1 is hurt by greater presence of 2 while 2 benefits from greater presence of 1 ```

Answer 75

character (trait) has undergone selection due to competition and species have differentiated the nature of their traits in response eg finches with large beaks vs small beaks in response to competition another example of how organisms can coexist

Answer 76

invasions are the result of increased dispersions | propagule is an organism that can start somewhere else, typically a seed

Answer 77

for transmitted pathogens - number of individuals that you will infect if you are infected while you have the disease influenced by duration of infectivity of affected patients, infectiousness of the organism, number of susceptible people in the population used in modeling disease

Answer 78

herd immunity - if enough people are vaccinated in a population, the disease can't really get started and move through the population threshold for this to be possible is the HIT

Answer 79

measles - highest R0 influenza - lower R0 than ebola ebola - zoonotic zika - zoonotic

Answer 80

states that moderate levels of disturbance foster greater species diversity than do high or low levels of disturbance high levels of disturbance reduce diversity by creating environmental stresses that exceed the tolerances of many species etc low levels can reduce diversity by allowing competitively dominant species to exclude less competitive ones intermediate: opens up habitats for occupation by less competitive species, rarely create severe conditions

Answer 81

ecological succession is when species are gradually replaced by other species, which are in turn replaced by still other species primary - process begins in a virtually lifeless area where soil has not yet formed, such as new volcanic island secondary - when an existing community has been cleared by some disturbance that leaves the soil intact; area may return to something like its original state

Answer 82

facilitation - early arriving species may facilitate appearance of later species by making the environment more favorable inhibition - early species may inhibit later species so that successful colonization by later species occurs in spite of, not because of, early species tolerance - early species may be completely independent of later species, which tolerate conditions created by earlier ones but are neither helped nor hindered

Answer 83

community's tendency to reach and maintain a relatively constant composition of species

Answer 84

the species and factors that make up a community

Answer 85

3-dimensional structure of communities as they develop

Answer 86

composition of species changes from place to place (in space)

Answer 87

how a community forms and assembles over time

Answer 88

linear sample | go along through an area, sample at a periodic distance, and see what organisms are there

Answer 89

at the edges of habitats (ecotones), ecological conditions are different resulting in different types of species specializing there microclimates can be different around edges also also important in conservation biology

Answer 90

area of transition between two different habitat types

Answer 91

elephant dung beetles and dung decomposition - many different organisms make use of dung from the moment that it is produced throughout its decomposition process

Answer 92

trophic structure - feeding relationships between organisms in a community

Answer 93

total mass of all organisms in a habitat

Answer 94

food chains are relatively short - why? energetic hypothesis - most common, suggests that length of a food chain is limited by the inefficiency of energy transfer along the chain; food chains should be longer in habitats of higher photosynthetic production, since the amount of stored energy in primary producers is higher body size/metabolic hypothesis - carnivores in a food chain tend to be larger at successive trophic levels, large carnivores generally cannot live on very small food items because they cannot obtain enough food to meet their metabolic needs; also carnivore size and feeding mechanism places an upper limit on size of food it can eat abundance/dynamic stability hypothesis -

Answer 95

food chains are not isolated units but are linked together in food webs ecologists diagram the trophic relationships of a community using arrows that link species according to who eats whom

Answer 96

= primary producers photoautotrophs - use light chemoautotrophs - use chemical compounds make their own food good for them

Answer 97

do not produce their own food like autotrophs (are consumers)

Answer 98

(herbivores) eat primary producers

Answer 99

(carnivores) eat primary consumers, tertiary eats secondary, etc etc

Answer 100

can eat either primary producers or primary consumers

Answer 101

food chains are relatively short - why? energetic hypothesis - most common, suggests that length of a food chain is limited by the inefficiency of energy transfer along the chain; food chains should be longer in habitats of higher photosynthetic production, since the amount of stored energy in primary producers is higher body size/metabolic hypothesis - carnivores in a food chain tend to be larger at successive trophic levels, large carnivores generally cannot live on very small food items because they cannot obtain enough food to meet their metabolic needs; also carnivore size and feeding mechanism places an upper limit on size of food it can eat abundance/dynamic stability hypothesis - all organisms have some randomness in numbers, so the few individuals at the top trophic levels may be more subject to chance events

Answer 102

bottom-up model: postulates a unidirectional influence from lower to higher trophic levels (presence or absence of mineral nutrients N controls plant V numbers, which control herbivore H numbers, which control predator P numbers) N-->V-->H-->P top-down model: postulates the opposite, predation mainly controls community organization because predators limit herbivores, which limit plants, which limit nutrient levels N

Answer 103

percentage of energy stored in assimilated food that is not used for respiration Production efficiency = (net secondary production x 100%)/assimilation of primary production

Answer 104

each tier represents the standing crop (the total dry mass of all organisms) in one trophic level most narrow sharply from primary producers at the base to top-level carnivores at the apex because energy transfers between trophic levels are so inefficient certain aquatic ecosystems have inverted biomass pyramids where primary consumers outweigh the producers (occur because producers are phytoplankton who grow and reproduce and are consumed so quickly by zooplankton that they never develop a large population size or standing crop = short turnover time)

Answer 105

species diversity is the variety of different kinds of organisms that make up the community and has two components: species richness - number of different species in a community relative abundance - proportion each species represents of all individuals in the community

Answer 106

relatively small area with numerous endemic species and a large number of endangered and threatened species highest conservation priority

Answer 107

species in a community that are the most abundant or that collectively have the highest biomass no single explanation for why a species becomes dominant, possibly because they are competitively superior at exploiting resources or because they are most successful at evading predation and disease

Answer 108

not usually abundant in a community but exert strong control on community structure by their pivotal ecological roles, or niches

Answer 109

(foundation species) | species that dramatically alter their environment, like beavers

Answer 110

can be on land, like lakes, mountain peaks separated by lowlands, or habitat fragments

Answer 111

any patch surrounded by an environment not suitable for the "island" species

Answer 112

amount of light energy converted to chemical energy in the form of organic compounds by autotrophs during a given time period

Answer 113

amount of chemical energy in consumers' food that is converted to their own new biomass during a given period

Answer 114

solar radiation that strikes the planet and then is reflected back into space

Answer 115

net primary production NPP = GPP - Ra Ra = amount of energy used by primary producers in their own respiration

Answer 116

net effective production NEP = GPP - Rt Rt = amount of energy used by all organisms as part of respiration

Answer 117

total dry mass of all organisms (can be thought of as similar to population size)

Answer 118

runoff adds considerable nutrients to lakes, promoting the growth of primary producers when primary producers die, detritivores decompose them, depleting the water of much or all of its oxygen

Answer 119

10% loss of energy at every trophic level, meaning that 10% intake by primary consumers of primary producers will result in 1% of NPP reaching secondary consumers and so on

Answer 120

trophic levels are arranged in tiers, width of each tier is proportional to the net production of each trophic level highest level, which represents top-level predators, represents relatively few individuals used to represent the loss of energy with each transfer in a food chain

Answer 121

photosynthesis by plants removes atmosphere CO2, converts carbon to organic forms that are used by consumers CO2 is added back to the atmosphere through cellular respiration by producers and consumers burning of fossil fuels and wood is adding significant amounts of additional CO2 to the atmosphere ocean acidification

Answer 122

functional groups that overlap some in resource use, but generally perform similar functions in the community

Answer 123

species can make use of resources in different ways which complement one another, can be more productive

Answer 124

number of species increases the closer you get to the equator tropics have highest species richness

Answer 125

evolutionary age/climate stability - climate in tropical regions has remained roughly the same, so there has been more time for these species to evolve and diversity for one another longer growing season/less seasonal variation - seasonal variation is lowest at the tropics, therefore the organisms have a longer period of time in any given season to mate and evolve more energy - more solar radiation at the equator because the sun is more directly overhead; food webs are enabled to be longer and more complex, more energy to be made use of by species (sun)/water/evapotranspiration spatial-area (null models) - tropics are largest in size

Answer 126

diversity at one place, richness in one area | high in the tropics (lots of species at each location)

Answer 127

diversity from one place to another | low in the tropics (species are the same from place to pace)

Answer 128

MacArthur and Wilson - equilibrium will eventually be reached where the rate of species immigration equals the rate of species extinction number of species at this equilibrium point is correlated with the island's size and distance from the mainlandisland equilibrium theory (Equilibrium Theory of Island Biogeography) not just oceanic islands, but also habitat islands assume: distance affects colonization island size affects extinction

Answer 129

MacArthur and Wilson - equilibrium will eventually be reached where the rate of species immigration equals the rate of species extinction number of species at this equilibrium point is correlated with the island's size and distance from the mainlandisland equilibrium theory (Equilibrium Theory of Island Biogeography) not just oceanic islands, but also habitat islands assume: distance affects colonization island size affects extinction

Answer 130

heat is transferred because two things are next to each other; the Earth is next to the atmosphere

Answer 131

atmosphere is actually moving so heat moves also

Answer 132

total amount of water transpired by plants and evaporated from a landscape useful predictor of NPP along with annual precipitation also another way that the Earth is warmed

Answer 133

result of eutrophication - oxygen has been removed from an aquatic ecosystem

Answer 134

weather patterns that tend to cycle every 5-7 years researchers unsure why these cycles occur typically begin with warm water in the Western Pacific which starts to accumulate, then spreads out to different parts of the world (el Nino) la Nina is opposite pattern implications for public health

Answer 135

nutrient cycles that involve both biotic and abiotic components energy flows but matter cycles

Answer 136

anything related to carbon is organic, anything else is inorganic (typically minerals)

Answer 137

available or unavailable for life to make use of it, used to categorize biosphere compartments eg available = living organisms, detritus unavailable = peat, coal, oil are not available as nutrients

Answer 138

movement of things between compartments of biosphere

Answer 139

when things move out of rocks or out of the atmosphere and become available for life, like minerals leaching out of the soil

Answer 140

nitrogen fixation NH2 to NH4 (ammonium), form that plants can use microbes turn NH4 into nitrates NO3 denitrification turns NO3 nitrates into N2

Answer 141

nucleid acids, phosphate PO4 | fertilizers, animal waste leading to eutrophicatio

Answer 142

chlorophyll synthesis, animal enzymes | limited in oceans, sinks

Answer 143

upper atmosphere: filters UV | ground level: leads to pollution, respiratory disease

Answer 144

disturb an ecological system so far that it cannot respond and will not be restored on its own

Answer 145

Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds

Answer 146

radiative forcing - difference of sunlight absorbed by the Earth and energy radiated back into space

Answer 147

examines organisms and their environment in urban settings | reflects a shift toward species preservation even in the context of cities