Ecology L7-L13

Question 1

pathogens

Answer 1

disease-causing microorganisms, viruses, viroids, or prions

produce especially clear effects when introduced into a new habitat, important in clear effects

Question 2

zoonotic pathogens

Answer 2

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

Question 3

vector

Answer 3

intermediate species through which pathogens can be transferred from one animal to another
eg lice, ticks, mosquitoes

Question 4

invasive species

Answer 4

organisms that become established outside their native range

Question 5

diseases

Answer 5

measles
influenza
ebola
zika

Question 6

“species turnover” (in space or in time)

Answer 6

turnover time means the species have a small standing crop compared to their production

Question 7

ecological succession

Answer 7

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 -

Question 8

role of earlier species in succession

Answer 8

facilitation -
inhibition -
tolerance -

Question 9

ecological succession

Answer 9

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

Question 10

role of earlier species in succession

Answer 10

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

Question 11

stability

Answer 11

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

Question 12

climax community

Answer 12

one stable equilibrium controlled solely by climate; theory that biotic interactions caused the species in the community to function as an integrated unit, though this has been disputed

Question 13

non-equilibrium community

Answer 13

describes most communities as constantly changing after a disturbance

Question 14

intermediate disturbance hypothesis

Answer 14

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

Question 15

food chain (length)

Answer 15

energetic hypothesis -
body size/metabolic hypothesis -
abundance/dynamic stability hypothesis -

Question 16

autotrophs

Answer 16

= primary producers
photoautotrophs -
chemoautotrophs -

Question 17

primary consumers

Answer 17

(herbivores)

Question 18

secondary, tertiary, etc consumers

Answer 18

(carnivores)

Question 19

ecosystem engineers

Answer 19

(foundation species)

Question 20

GPP

Answer 20

gross primary production

Question 21

NPP

Answer 21

net primary production

Question 22

NEP

Answer 22

net ecosystem production

Question 23

species diversity

Answer 23

species richness -

relative abundance -

Question 24

detritivores, decomposers

Answer 24

detritivores, synonymous with decomposers - consumers that get their energy from detritus
detritus is nonliving organic material, such as the remains of dead organisms, feces, fallen leaves, and wood

Question 25

primary production

Answer 25

starting pothe amount of light energy converted to chemical energy, in the form of organic compounds, by autotrophs during a given time period int for most studies of ecosystem metabolism and energy flow

Question 26

secondary production

Answer 26

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

Question 27

GPP

Answer 27

gross primary production amount of energy from light (or chemicals, in chemoautotrophic systems) converted to the chemical energy of organic molecules per unit time not all of this production is stored as organic material because primary producers use some as fuel in their own cellular respiration

Question 28

trophic interactions/structure

Answer 28

trophic structure - feeding relationships between organisms in a community

Question 29

biomass

Answer 29

total mass of all organisms in a habitat

Question 30

food chain (length)

Answer 30

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 -

Question 31

food web

Answer 31

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

Question 32

production efficiency

Answer 32

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

Question 33

autotrophs

Answer 33

= primary producers photoautotrophs - use light chemoautotrophs - use chemical compounds

Question 34

heterotrophs

Answer 34

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

Question 35

primary consumers

Answer 35

(herbivores) eat primary producers

Question 36

secondary, tertiary, etc consumers

Answer 36

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

Question 37

omnivores

Answer 37

can eat either primary producers or primary consumers

Question 38

bottom up vs top down models

Answer 38

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

Question 39

trophic cascades

Answer 39

trophic cascade model is the same as top-down model, says that highest levels like predators control or limit the organisms beneath them

Question 40

biomass pyramid

Answer 40

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)

Question 41

species diversity

Answer 41

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

Question 42

hypotheses

Answer 42

``` evolutionary age/climate stability longer growing season/less seasonal variation more energy (sun)/water/evapotranspiration spatial-area (null models) ```

Question 43

evapotranspiration

Answer 43

total amount of water transpired by plants and evaporated from a landscape useful predictor of NPP along with annual precipitation

Question 44

main greenhouse gases

Answer 44

``` carbon dioxide CO2 methane CH4 nitrous oxide N2O water H2O ozone O3 ```

Question 45

limiting nutrient

Answer 45

element that must be added for production to increase nutrient most often limiting marine production is either nitrogen or phosphorus, typically taken up by phytoplankton and therefore low in the photic zone

Question 46

biodiversity hotspot

Answer 46

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

Question 47

endemism

Answer 47

species that are found nowhere else in the world

Question 48

nature reserve

Answer 48

protected "islands" of biodiversity in a sea of habitat altered or degraded by human activity

Question 49

buffer zone

Answer 49

habitats surrounding the undisturbed parts of a zoned reserve that protect against further intrusion into the undisturbed area

Question 50

zoned reserve

Answer 50

extensive region that includes areas relatively undisturbed by humans surrounded by areas that have been changed by human activity and are used for economic gain key challenge - to develop a social and economic climate in the surrounding land that is compatible with the long-term viabiity of the protected core

Question 51

albedo

Answer 51

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

Question 52

greenhouse effect

Answer 52

much of the solar radiation that strikes the planet is reflected back into space; greenhouse gases like CO2, methane, and water vapor in the atmosphere intercept and absorb much of the infrared radiation Earth emits, re-reflecting some of it back towards Earth this process retains some of the solar heat keeps average air temperature of Earth from being too frigid for life

Question 53

carbon cycle

Answer 53

ocean acidification

Question 54

restoration ecology

Answer 54

physical reconstruction - bioremediation - biological augmentation -

Question 55

drivers of global change

Answer 55

``` fragmented landscape disrupted adjacent areas transformed landscapes (agriculture, urban areas) accumulated impacts (dead zones) changes in atmosphere/ocean chemistry conifers changed (killed, moving) biodiversity lost glaciers melting ```

Question 56

species-area relationship (curve)

Answer 56

all other factors being equal, the larger the geographic area of a community, the more species it has, in part because larger areas offer a great diversity of habitats and microhabitats

Question 57

island equilibrium theory

Answer 57

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 mainland not just oceanic islands, but also habitat islands

Question 58

habitat islands

Answer 58

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

Question 59

habitat fragmentation

Answer 59

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

Question 60

eutrophication

Answer 60

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

Question 61

biogeochemical cycle

Answer 61

nutrient cycles that involve both biotic and abiotic components

Question 62

water (hydrologic) cycle

Answer 62

evaporation of liquid water by solar energy condensation of water vapor into clouds precipitation transpiration by terrestrial plants also moves large volumes of water into the atmosphere surface and groundwater flow returns water to the oceans

Question 63

carbon cycle

Answer 63

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

Question 64

drivers of global change

Answer 64

``` fragmented landscape disrupted adjacent areas transformed landscapes (agriculture, urban areas) accumulated impacts (dead zones) changes in atmosphere/ocean chemistry conifers changed (killed, moving) biodiversity lost glaciers melting ```