Exam 2 Flashcards
Condition
Abiotic environment that varies in time and space and to which organisms respond differently.
Components of condition
Temperature, pH, humidity, water flow rate
Resource
Factor that organisms may use up and make less available for others
Performance of Species graph
Species that survive may not be able to grow or reproduce. Species that grow may not be able to reproduce.
Homeotherms
Approximately constant body temperature. “Hot blooded”
Poikilotherms
Variable body temperature. “Cold Blooded”
Endotherms
Heat generated internally
Ectotherms
Heat from environment
A lot of hibernating animals are this
Poikilotherms
Behavioral thermoregulation
Can control body temperature based on behavior
Advantage of Ectothermy
Generally low cost. Plants can put more towards growth than towards thermogenic machinery. Choice of environment limited though
Advantage of Endothermy
Can exploit more environments. High energy cost though
Short wavelengths provide…
More energy
Photosynthetically active radiation (PAR)
Radiation that can be used by plants
Enhanced Greenhouse Effect
Infrared rays get into earth and cannot escape. If at an increased rate then can’t escape atmosphere
El Nino Southern Oscillation (ENSO)
Warm water is sloshed back to South America and cold water is covered, resulting in less nutrient for wildlife, productivity decreases
Red Kangaroo Population during ENSO
Declined. Droughts reduced amount of vegetation kangaroos could eat.
Grasshopper thermoregulation
Change pigment. Increase potential for Hr gain (dark) or Decrease potential for Hr gain (light)
Torpor
State of low metabolic rate and low metabolic temperature
Hibernation
Torpor happening during the winter
Estivation
Torpor happens during the summer
Greenhouse Effect
Atmosphere keeps surface of Earth warm. Gasses absorb infrared radiation emitted by solar heated earth and re-emit most energy back to the earth.
Walker Circulation
Air over warmer Western Pacific rises, flows eastward in the upper atmosphere, then sink over eastern pacific. Air mass then flows westward along southeast trade winds, gradually warming and gathering moisture. Western flowing air eventually joins the rising air in the western pacific. As warm and moist air rises, it forms rain clouds
La Ninas
Periods of lower sea surface temperature and higher than average barometric pressure in the eastern tropical pacific
Effects of El Nino
Easterly winds slacken and warmer waters come in. Upwelling on coast is shut down and supply of nutrients shut off
El Nino Effect on Great Salt Lake
Lowered salinity levels allowed predacious corixid bugs to move into limnetic zone. Corixids reduced Artemia, main grazing zooplankton species. As response phytoplankton biomass increased.
Pedology
The study of soils
Soil
A mixture of inorganic materials (clay, silt, pebbles, sand) , decaying organic matter, water, air, and living organisms
Role of Soil
Ecosystem: Nutrient delivery system, recycling system, waste disposal system
Plants: Site of germination, nutrients, support, decay
Animals: Refuge, sewer, or a complete habitat
Decomposers: Resource
O-Horizon
Surface litter. Freshly fallen organic matter. Usually absent in agricultural soils and deserts
A-Horizon
Topsoil. Partially decomposed organic matter (humus) living organisms, and some inorganic minerals
E-Horizon
Zone of Leaching. Dissolved or suspended material move downwards
B-Horizon
Subsoil. Accumulation of Fe, Al, humic compounds, and clay leached from above regions
C-Horizon
Parent material. Partially broken down inorganic materials.
R soil layer
Impenetrable layer. Cracks allow water to go up
Soil characteristics
Texture, porosity, permeability
Soil texture
Fine textured: Clay
Coarse textured: Sand
Loamy soil is best for farming
Soil Porosity
Number of pores per unit of soil
Soil Permeability
Determined by size of pores
What do soil characteristics determine?
Water holding capacity, aeration, susceptibility to erosion, CEC, workability
Types of Parent materials
Loess, Alluvium, Lacustrine,Till, Marine, Residual
Parent Material
Rise of geological materials that make up soil
Loess
Parent Material transported by wind
Alluvium
Parent material transported by running water
Lacustrine
Parent material transported by lake action
Till
Parent material transported by glacial ice
Marine
Parent material transported by oceans
Residual
Parent material that remains in place
Major Types of Soil Forming Processes
Gleizations, Calcification, Podzolization, Laterization
Gleization
Happens in tundas.
O-Horizon: High organic with reduced Fe. Anaroebic, few organisms, slow decomposition
A and E-Horizons: ICE - Surface flooding. Little leaching below these layers
Podzolization
Coniferous and Deciduous Forests
O-Horizon: Trees take up little Calcium
A- and E-Horizons: High rain leaches salts and Fe and Al. White color because Si left behind
B-Horizon: Deposited Fe, Al (clays). Yellow/brown. Can be hardpan and impede water and air
Calcification
Grasslands
O-Horizon: Litter Ph~7. Less leaching, less rain. A lot of invertebrates. Organic matter mixed annually. Grass roots return Ca to upper soil layers.
A and E-Horizons: High organic content and thick
B-Horizon: Indistinct
Lateralization
Tropical Rain Forest
O-Horizon: Barely present because of high temp and moisture and high decomp. A lot of weathering, mostly chemical via water
A- and E-Horizons: Intense leaching of salts. Clay (Fe and Al) left behind. Fe oxidized. (ferric)-red soil. Indistinct Horizons
Community
An association of interacting species inhabiting some defined area
Community ecology
The study of collective properties in the structure of multi species biological assemblages
Collective properties
- Species richness
- Species Diversity
- Dominancy
- Frequency
- Trophic structure
- Stability
Primary question in community ecology
Are there patterns in time or space in community properties even when species are very different?
Three Issues in community definitions
1) Co-occurence
2) Recurrence
3) Communities tend toward dynamic stability (slow)
Two Major Views of Communities
1) Individualistic School (H.A. Gleason)
2) Superorganism School (F.E. Clements)
Individualistic School
- Co-Occurence
- An abstraction of continuously varying vegetation
- Useful concept, but not a fundamental description of nature
- A collection of populations with similar environmental requirements
Superorganism School
- Tightly coevolved in evolutionary time
- Important in ecological time
- not just an invention of ecologists
- Species importance value distribution in clear pattern for superorganism. Usually in nature, distribution is random
Gaia-Hypothesis
Earth can respond as a “super-organism”
The problem with this hypothesis is that it implies we can do anything to the earth
Hypothesis for increased species richness at lower latitudes
1) Rate of evolution increases in tropics than in temperate zones
2) Stability-time: Tropics have been stable for longer periods of time. Evolution occurs
- Turns out tropics aren’t that stable
3) Rate of colonization, not rate of evolution, is limiting in temperate zone
4) Tropics are less seasonal than temperate zone
5) Spatial (architectural heterogeneity)
6) Greater species-specific predation in the tropics
7) Productivity: Tropics more productive, possibility of more trophic levels
- not really valid
Community Structure
Refers to the absolute and relative abundance of species in a community
Focus of community structure
what factors produce given patterns of species abundance. Not just how many species but which ones
Major community structuring forces
- interspecies competition
- predation
- disturbance
Strong interactions
Some species have a strong effect on community structure. ex. Starfish pisaster on california mussels
Keystone Species
Organisms whose feeding activity strongly control community structure
Disturbance
Any relatively discrete event in time that disrupts ecosystem, community or population structure and changes resources, substrate availability, or the physical environment
Abiotic sources of disturbance
Fire, hurricanes, ice storms, flash floods
Biotic sources of disturbances
Disease, predation
Human-caused
Timber harvesting, road/bridge construction
Intermediate Disturbance Hypothesis (IDH)
Species should be highest at medium disturbance.
Australian Coral Reef demonstrating IDH
Have damaged and undamaged coral. Very similar to hypothetical curves
Species Diversity
Species Richness and evenness
Climax Community
Vegetation formation resulting from many years of development
Biomass based on climax community
- Temperate deciduous forest
- Coniferous forest
- Tropical rain forest
Succession (climax community)
Non-seasonal, directional, and continuous pattern of colonization and extinction on a site by populations of a species
3 traditional views of successional process
- Facilitation
- Tolerance
- Inhibition
Facilitation
- monoclimax
- one climax community for every climatic region that all stands of vegetation inevitably move towards
- Successional mechanism is facilitation
- ex glacial moraines on Glacier Bay, AK
Facilitation as a mechanism
Each species in the sequence modifies the environment to make it more suitable for the next species
Tolerance
- Similar to facilitation- later species outcompete earlier ones
- different from facilitation-early species don’t make environment more favorable to later ones
- Sequence of species a result of colonizing ability, reproductive rates, growth rates, and competitive abilities
- eg. sand dunes
Characteristics of later species in Tolerance scenario
Fewer, less propagules, slower growth rates, but higher competitive abilities
Inhibition
-Opposite of facilitation
-each species inhibits colonization by subsequent species
-External force required for succession to proceed
competition not a driving force in succession
-eg. old field succession and rocky intertidal
Algae of Rocky intertidal
- Ulva sp. is an early successional species
- Red algae started replacing it in milder storm years
- studies show that intermediate sized rocks that take intermediate force to turn over has highest algal density
Old field succession
Old farmland will provide succession for plant community
Temperate deciduous Forests
- Cold winters
- local variations: wet > dry
- abundant understory
Coniferous forests
- Boreal forest- northern tier of forest areas, aka taiga
- spruce and fir but also some aspen and birch
- Cold with moderate amounts of precipitation
- abundant understory
Temperate Rain Forest
- western edge of north and south america
- a lot of rainfall
- considerable amounts of seasonal variation
- mixture of conifers and deciduous trees
- Canopy layer, understory layer, ground layer
Tundra
- alpine area north of boreal forest
- low precip. permafrost
- relatively low biological diversity
- simple vegetation structure- low growth forms
Grasslands
- middle latitudes in interior of continents
- adequate precip. to support grasses
- occasional droughts
- Tall grass and shortgrass prairies
Savanna
- Grasslands with scattered trees
- less rainfall and soils not as rich as in grasslands
- Fire-very important
- High biological diversity
Shrubland (chaparral)
- Short, densely branching shrubs
- Winters: Mild and rainy
- Fire and drought: very important
Deserts
- 20% of earth’s surface
- Hot and cold deserts
- Conflicting definitions: Most based on floristic composition and distribution. Some use animal composition or both and other criteria
Hot deserts
- Chihuahuan, Sonoran, Mojave, Sahara
- Drought conditions year round. 15 cm precip. per year
- Temp > 30 degrees Celsius commonly
- Not many plants
- Burrowing animals
Cold deserts
- Great basin, Gobi, Atacama, Namib
- Precip. mainly snow or fog
- Large temp. changes
- Mosses, a few grasses
- Burrowing animals
Tropical Rain forest
- <6% of Earth’s surface
- Temp. rarely > 34 degrees celsius or < 20 degrees celsius
- Precip. 125-660 cm per year
- > 50% of known plant and animal species
- ~25% of all known medicines
- A biome of tall, straight trees
