quiz 3 Flashcards
(64 cards)
disturbance
an event that changes a community, removes organisms from the area, and alters resource availability
why does succession occur?
- the result of changes induced by vegetation itself
- early-arriving & later arriving species may be linked in 1 of these processes:
1. early arrivals facilitate the appearance of later species by modifying the environment so it is less favourable for the success of existing plants and more favourable for the invasion and growth of other plants
2. may inhibit the establishment of later species
3. may tolerate later species but have no impact on their establishment
what are the 3 main changes in community structure that categorize ecological succession
- general increase in community diversity
- general increase in abundance of organisms
- general change in size and longevity, decrease in birth rates
primary succession
- no soil exists
- pioneer species : prokaryotes, protists, fungi
- over hundreds-thousands of years
secondary sucession
- begins where soil remains after a disturbance
- earliest recolonizers are seeds ( by wind and animal dispersion )
- about 50-200 yrs
compare and contrast primary and secondary succession, specifically identify the similarities between the between processes, the conditions that exist at the beginning of each type of succession, the potential sources of new species in each and the time frame over which each type of succession occurs
similarities:
- natural ecological processes = gradual development of an ecosystem over time
- increase in biodiversity = diversity increases as ecosystem progresses and develops
- involves pioneer species = both processes begin with pioneer species that help modify the environment
- community formation = succession leafs to the establishment of a stable and mature ecosystem
differences:
starting conditions:
- primary succession begins in an area where no previous ecosystem existed, like bare rock. Environment is harsh, lacking soil and organic matter
- secondary succession occurs in areas where an ecosystem previously existed but was disturbed. there is soil present and potentially organisms that survived the disturbance
sources of new species:
primary - arrives through wind, water, and animal dispersal. lichens and mosses are often the first to colonize and form soil
secondary - species may regenerate from seeds, roots, spores that survived in the soil
time frame:
primary - hundreds to thousands of years, soil formation must occur before plants and animals can establish
secondary - proceeds more quickly, about 50-200 years, since soil is already present and the ecosystem can recover, not be discovered
why are pioneer species replaced by other species during succession?
- changes in environmental conditions
- alter soil properties, permitting new plant species to grow, altering environment to make it suitable for larger, more competitive species to establish
- when they die they enrich the soil with nutrients
lichens as pioneer species
- fixing carbon and nitrogen levels
- breaks down rock and exposes minerals
- traps windblown soil
- retains water
ecosystem
the community of organisms in an area and the physical factors with which they interact
biomes
major types of ecosystems
occupies broad geographic areas
biosphere
sum of the planet’s ecosystems
climate
the long term prevailing weather conditions
- the 4 major abiotic components of climate are:
-> temperature, precipitation, sunlight, wind
macroclimate
global, regional, and landscape climate patterns
microclimate
consists of very fine local patterns (like under a fallen log)
latitudinal variations in climate
global climate patterns are determined by solar energy and earth’s movement
- the angle of sunlight hitting the earth affects its intensity
- temperature variations determine patterns of evaporation and circulation of air and water
global air circulation and precipitation
- water evaporates in the tropics, and warm wet air masses flow from tropics to the poles
- rising air masses release water and cause high precipitation, esp in the tropics
- cooling trade winds flow east to west in the tropics
- prevailing westerlies blow from west to east in temperate zones
terrestrial biomes
i) forests : tropical rainforest, coniferous forest, temperate deciduous
ii) savanna, temperate grasslands, chaparral
iii) desert, tundra
ecotones
areas where terrestrial biomes blend into each other
- no sharp boundaries
- could be wide or narrow
major aquatic biomes can be characterized by
- physical environment
- geological features
- chemical environment
- photosynthetic organism
- heterotrophs
- marine biomes have a salt concentration of 3%, freshwater less than 0.1%
aquatic biomes
- open oceaen
- coral reefs
- wetlands
- estuaries and intertidal
- lakes, streams, rivers
what is primary production?
the amount of light energy converted into chemical energy (in Joules) by autotrophs during a given time period
-> sets the spending limit for an ecosystem’s energy budget
explain the difference between gross primary production and net primary production
gross = total primary production
net = total, minus energy used for respiration/metabolism
-»» amount of new biomass in a given time period
*** this is what is available to consumers
which of the terrestrial biomes have the highest and lowest NPP? include abiotic conditions of each
highest:
Tropical Rainforest
- warm temperature
- high precipitation rates
- abundant sunlight, warm climate
=> optimal for photosynthesis = high biodiversity and productivity
lowest:
Desert
- minimal precipitation and high temperature => limits plant growth and water accessibility
- nutrient poor soils
which of the aquatic biomes have the highest and lowest NPP? include abiotic conditions of each
highest:
Coral Reefs
- warm, shallow waters
- abundant sunlight
- constant nutrient cycling
lowest:
Deep Open Ocean
- limited nutrients
- minimal sunlight