Ecology Exam II

Large Scale Spatial Variation

Spatial variation via climate, land topography, and soil type

Small Scale Spatial Variation

Spacial variation via plant structure and animal behavior

Phenotypic Tradeoff

Where one phenotype is in a higher fitness in one environment, while a different phenotype has a higher fitness in a different environment.

Phenotypic Plasticity

Ability of a genotype to produce multiple phenotypes in response to different environmental conditions

Acclimation

An environmentally induced changed in an individual’s physiology

Adaptation

the process of evolution through natural selection

Microhabitat

location within a habitat that differs in environmental conditions from the rest of the habitat

Above Sea Level

Air pressure becomes lower and reduces the amount of available oxygen

Dormancy

A condition in which organisms dramatically reduce their metabolic processes

Optimal Foraging Theory

Model that predicts foraging behavior based on the premise that animals should forage in a manner that obtains the most benefit at the lowest cost.

Central Place Foraging

Foraging behavior in which acquired food is brought to a central place

Risk Sensitive Foraging

Foraging behavior that is influenced by the presence of predators

Weather

Variation in temperature, precipitation, and other atmospheric variables over periods of hours to days.

Climate

Typical atmospheric conditions that occur throughout the year, averaged over many years.

Greenhouse Effect

process of solar radiation striking earth, being converted to infrared radiation, and being absorbed and re-emitted by atmospheric gases.

Primary Greenhouse Gases

H2, CO2, N2O, CH4, O3

Albedo

Fraction of solar energy reflected by a surface

Low Albedo

increase average temperatures, ex: dense forests

High Albedo

decreases average temperatures, ex: snow and ice at the poles

Solar Equator

Latitude where the sun is directly overhead at noon. Varies depending on the year.

Adiabatic Cooling

decline in air temperature resulting from reduced pressure as air rises higher in the atmosphere and expands.

Adiabatic Heating

Increase in air temperature resulting from increased pressure as it sinks towards the ground and is compressed.

Saturation Point

Maximum amount of water vapor that air can hold at a given temperature

Hadley Cells

Two circulation cells of air between the equator and 30N and 30S latitudes

Intertropical Convergence Zone

Area where the two Hadley cells converge and cause large amounts of precipitation

Polar Cells

Atmospheric convection currents between 60-90 latitudes, similar to Hadley cells

Coriolis effect

Deflection of an object’s path due to the rotation of the earth.

Northeast Trade Winds

Air moving along the earth’s surface within the northern Hadley cell is deflected so that it moves from the northeast to the southwest

Southeast Trade Winds

Air moving along the surface within the southern Hadley cell is deflected to the northwest

Westerlies

Winds in the mid-latitudes that move from west to east

Gyres

Large-scale water circulation in the oceans, clockwise in the north hemisphere and counterclockwise in the southern.

Upwelling

An upward movement of ocean water

Rain Shadow

A region with dry conditions found on the leeward side of a mountain range as a result of humid winds from the ocean causing precipitation on the windward side.

Biome

A geographic region that contains communities composed or organisms with similar adaptations

Growth Form

The physical structure of a plant, such as tree, shrub, succulent, graminoid, for, vine, etc…

Terrestrial Biomes

Categorized by their major plant growth forms and climate.

Convergent Evolution

A phenomenon in which two species that descended from unrelated ancestors have similar adaptations because they have evolved under similar selective forces.

Tropical Rainforests

• Warm and rainy biome

• plant growth not limited by water or low temperatures

• more productive and species rich than anywhere else in the world

• canopy of 30-50m trees with an understory containing smaller trees, shrubs, epiphytes, and vines

• organic matter decomposes quickly

• vegetation rapidly takes up nutrients

• soils have little organic matter and retain nutrients very poorly, most of the nutrients are in the vegetations rather than the soil.

Tundras

• Plant growth limited by temperature

• coldest biome, characterized by a treeless expanse above permanently frozen soil

• upper soils thaw during the brief summer growing season

• soils are acidic and nutrient poor.

• decomposition is slow

• plants grow low to the ground to gain protection under snow and ice in winter

• alpine tundra occurs at high elevations in temperature and tropical latitudes

Subtropical Deserts

• plant growth limited by water

• hot temperatures scarce rainfall, long growing seasons, and sparse vegetation

• associated with dry, descending air of Hadley cells

• soils are shallow, contain little organic matter, and pH neutral

• succulent CAM plants are common

Savannas

• Warm temperatures and pronounced wet and dry seasons dominated by deciduous trees that shed leaves during the dry seasons.

• dominated by C4 grasses and occasional trees

• fire and large herbivores in savannas keep tree density lower than what the climate could support.

Temperate Grasslands

• characterized by hot, dry summers and cold winters

• dominated by grasses, non-woody flowering plants, and drought-adapted shrubs

Mediterranean Woodlands

• characterized by hot, dry summers and mild, wet winters, favoring the growth of drought-tolerant shrubs

• 12-month growing season, but dry summers, cold winters, and frequent fires limit plant growth

• dominated by sclerophyllous vegetation, which has small, tough leaves that resist desiccation

Boreal Forests

• Dominated by evergreen needle-leaved trees, with a short growing season and severe winters.

• acidic and nutrient-poor soils

• low species diversity

Temperate Rainforests

• mild temperatures and abundant precipitation, and dominated by evergreen forests.

• mild climates result from nearby ocean currents

• low species diversity

Temperate Seasonal Forests

• moderate temperature and precipitation conditions, dominated by deciduous trees

• conditions fluctuate because forests are not near warm ocean currents

• precipitation exceeds transpiration

• slightly acidic soils that support a layer of small plants beneath the dominant trees.

• warmer and drier parts of the biome are dominated by pines.

Ecotones

Regions where two communities or ecosystems overlap

Lotic

Characterized by flowing water

Riparian Zone

Terrestrial vegetation alongside rivers and streams that is influenced by seasonal flooding and elevated water tables.

Littoral Zone

the shallow area around the edge of a lake or pond containing rooted vegetation

Limnetic Zone

Open water beyond the littoral zone, where the dominant photosynthetic organisms are floating algae.

Profundal Zone

Area in a lake that is too deep to receive sunlight, typically has low oxygen concentrations

Benthic Zone

Area with sediments at the bottom of lakes, ponds, and oceans, is habitat for burrowing organisms.

Stratification

Condition of a lake or pond when the warmer, less dense surface water floats on the cooler, denser water below.

Epilimnion

Surface layer of water in a stratified lake

Hypolimnion

Deep layer of water in a lake

Spring Overturn

The vertical mixing of lake water that occurs in early spring, assisted by winds that drive the surface currents

Fall Overturn

Vertical mixing that occurs in fall, assisted by winds that drive the surface currents

Fall Bloom

Rapid increase in the population of phytoplankton that occurs with an infusion of nutrients

Freshwater Wetland

• contains standing fresh water, or soils saturated with fresh water for at least part of the year

• shallow enough for emergent vegetation throughout all depths

Salt Marshes

• contains non-woody emergent vegetation

• often found at continental coasts and in estuaries where the mouths of rivers mix with salt water from oceans

Estuaries

• contain abundant nutrients and sediments carried downstream by rivers

Mangrove Swamps

• occurs along tropical and subtropical coasts and estuaries

• contain salt-tolerant trees with roots submerged in water

• mangrove trees prevent the erosion of shorelines from incoming waves

• provide habitat for many species of fish and shellfish

Intertidal Zones

• consist of the narrow band of coastline between the levels of high and low tide

• water exhibits widely fluctuating temperatures and salt concentrations

Neritic Zone

Ocean żonę beyond the range of the lowest tidal level, extending to the edge of the continental shelf.

Region of high productivity with high light and nutrients

Oceanic Zone

Ocean zone beyond the neritic zone, nutrients are sparse and production is limited

Photic Zone

Area of the neurotic and oceanic zones that contain sufficient light for photosynthesis by algae.

Aphotic Zone

Area of the neritic and oceanic zones where water is so deep that sunlight cannot penetrate.

Low productivity, food web is largely dependent on detritus rain from above.

Stress

Condition that reduces production

Disturbance

Event that causes partial or total destruction of plant biomass

Stress Tolerators

Small herbs or shrubs with a long life span, slow growth, and a long time to sexual maturity

Competitors

Grow relatively fast, achieve sexual maturity fairly early, and devote relatively little energy to seed production.

Ruderals

Grow extremely fast, reach sexual maturity very quickly, and devote a high proportion of their energy to reproduction.

Principle of Allocation

When resources are allotted to one body structure, physiological function, or behavior, they cannot be allotted to another.

Determinate Growth

A growth pattern in which an individual does not grow any more once it initiates reproduction

Indeterminate Growth

Growth pattern in which an individual continues to grow after it initiates reproduction.

Semelparity

When organisms reproduce only once during their life

Iteroparity

When organisms reproduce multiple times during their life

Annual

An organism that has a life span of one year

Perennial

An organism that has a life span of one year

Senescence

A gradual decrease in fecundity and an increase in the probability of mortality

Many Eyes Effect

More eyes to watch for predators

Dilution Effect

Reduced risk to be specifically spotted by a predator

Donors

Individuals initiating behaviors

Recipients

Individuals toward whom behaviors are directed

Cooperation

Donor and the recipient of a social behavior both experience increased fitness from an interaction

Selfishness

Donor of a social behavior experiences increased fitness, recipient experiences decreased fitness

Spitefulness

Social interaction reduces fitness of both donor and recipient

Altruism

Increases recipient fitness and decreases fitness of the donor

Indirect Fitness

Fitness gained by helping a relative pass on to its offspring copies of genes that the relative shares with you.

Direct Fitness

Fitness gained by passing on copies of your genes to your offspring.

Inclusive Fitness

Sum of direct and indirect fitness

Coefficient of Relationship, r

Probability that two relatives share copies of the same gens from a common ancestor

Hamilton’s Model

A behavior is favored by natural selection if the indirect fitness benefit is greater than the direct fitness cost

Dispersal Limitation

A factor that prevents an organism from arriving at a new location

Fundamental Niche

Range of abiotic conditions under which a species can persist

Realized Niche

Actual range of environmental conditions utilized by a species when other species are present

Competitive Displacement

A reduction in the range of conditions that a species occupies, due to competition with other species

Vegetative Reproduction

A form of asexual reproduction in which an individual plant is produced from the nonsexual tissues of a parent.

Binary Fission

Asexual reproduction in single-celled species occurring through duplication of genes followed by division of the cell into two identical cells