ENSC 1003 - Wood - Exam 2

Chaparral

-"Wild West" -hot and dry -Sierra Nevadas

Humans use about ____% of net terrestrial primary productivity by consuming it directly, by interfering with its production or use, or by altering species composition or physical processes.

40

Equilibrium Theory.

MacArthur and Wilson proposed that species diversity is a balance between colonization and extinction rates

Biotic Factors

caused by living organisms, tend to be density dependent.

Abiotic Factors

caused by non-living environmental components. -tend to be density independent, and do not really regulate population, although they may be important in increasing or decreasing numbers.

Salt marshes

coastal wetlands flooded regularly or occasionally by seawater -both are nutrient rich and biologically diverse. -2/3 of marine fish and shellfish rely on estuaries for spawning and development. -threatened by sewage from coastal cities

Hypolimnion

cold, deeper layer that does not mix

Intraspecific Interactions

competition for resources by individuals within a population

Exponential Growth Function

dN/dt=rN a model for population -d is for delta which represents change. -thus the formula would read: "the change in the population (dN) per change in time (dt) is equal to the rate of change (r) times the population size (N)."

Tide Pools

depressions in a rocky shoreline that are flooded at high tide but retain some water at low tide -wave action prevents most plant growth, but animals can be found in tidal pools. -diverse specialized species adapted to the harsh conditions.

Thermocline

distinctive temperature transition zone that separates warm upper layer and deeper cold layer

Density Independent

factors include drought, fire, or other habitat destruction that affects an ecosystem

Lakes

freshwater lakes have distinct vertical zones.

Survivorship Curves

full physical lifespan if organism survives childhood, probability of death unrelated to age, mortality peaks early in life

Density Dependent

growth rate depends on the population density -factors intensify as population size increases -factors can influence a population including: disease, physiological stress and predation.

K-Selected Species

have few offspring, slower growth as they near carrying capacity and exercise more parental care. -ex: an elephant produces one offspring every 4 or 5 years, but nurturing by a herd increases the likelihood of it surviving to maturity.

Extrinsic Factors

imposed from outside the population

Coral Bleaching

in which corals expel their algal partners and then die -threatened by trash, sewage, urban runoff, industrial waste, introduced pathogens and global warming. -global warming is a cause -1/3 of coral reefs have already been destroyed and 60% of the remaining reefs will probably be dead by 2030

Open ocean

is a biological desert except for areas where nutrients are distributed by currents ex: Sargasso Sea in the Atlantic is known for free-floating mats of brown algae

Genetic Drift

is a change in gene frequency due to a random event.

Metapopulation

is a collection of populations that have regular or intermittent gene flow between geographically separate units

Logistic Growth

is density-dependent which means that the growth rate depends on the population density.

Minimum Viable Population

is the minimum population size required for long-term survival of a species.

Wetlands

land surface is saturated or covered with water at least part of the year. -irreplaceable, water filtration, water storage, flood reduction and habitat

Vertical Stratification

light and temperature decrease with depth and deep ocean species grow slowly -cold water holds more oxygen

Arctic tundra

low productivity, long winters, permafrost

Barrier Islands

narrow islands made of sand that form parallel to a coastline -provide protection from storms, waves, tides -about 20% in the US have been developed.

Founder Effect

occurs when a few individuals start a new population

Demographic Bottleneck

occurs when just a few members of a species survive a catastrophic event such as a natural disaster

Alpine tundra

on or near mountaintops; short intense growing season

Exponential Growth

only can be maintained by a population as long as nothing limits its growth. -in the real world there are limits to growth that each population will encounter. -eventually shortages of food or other resources lead to a reduction in the population size.

Intrinsic Factors

operate within or between individual organisms in the same species

S-Shaped Growth Curve.

population growth slows down as resources become scarce and a population nears its carrying capacity. - dN/dt = r N (1 - N/K)

Births, Immigration, Deaths and Emigration Equation

r=B+I-D-E

Biotic potential

refers to unrestrained biological reproduction. -biological organisms can produce enormous numbers of offspring if their reproduction is unrestrained. -ex: the house fly: 1 female can have 120eggs (56 days to mature = 7 generations per year), the only constraint is we kill them

Biomes

regions of the world with similar climate, topographic, soil condition - same basic types of biological community

r-Selected Species

rely upon a high reproductive rate to overcome the high mortality of offspring with little or no parental care. -ex: a clam can release a million eggs in a lifetime, with few surviving to maturity.

Island Biogeography

small islands far from the mainland have fewer terrestrial species than larger, closer islands

The most important determinants of biome distribution?

temperature and precipitation

Maximum Life Span

the longest period of life reached by a given type of organism -bristlecone pines can live up to 4,600 years. -humans may live up to 120 years. -microbes may live only a few hours.

Carrying Capacity (K)

the population of a species that can be supported in a specific area without depleting the available resources.

Geometric Rate of Increase

the population size that would occur after a certain amount of time under ideal conditions is described by the formula: Nt = N0rt

Soil in rainforests tend to be...

thin, acidic and nutrient poor. -90% nutrients tied up in living organisms -rapid decomposition and nutrient cycling -cannot support continued cropping and cannot resist erosion from frequent rains.

Rate (r)

this is the rate of growth; the number of individuals which can be produced per unit of time under ideal conditions (with no limits to the population's growth).

Time (t)

this is the unit of time upon which the rate is based.

Population (N)

total number of all the members of a single species living in a specific area at the same time.

Epilimnion

warm upper layer

Pelagic

water column above the bottom

Bogs/Fens

waterlogged soil that tend to accumulate peat

Swamps

wetlands with trees

Marshes

wetlands without trees

Overshoot

when a population exceeds the carrying capacity of the environment and deaths result from a scarcity of resources.

Boom and Bust

when a population undergoes repeated cycles of overshoots followed by crashes

Boreal Forest

-Northern Coniferous Forest -broad band of mixed coniferous and deciduous trees between 50° and 60° N latitude -dominated by pines, hemlock, spruce, cedar and fir with some deciduous trees mixed in Siberia, Canada, and Northwestern U.S.

Biotic potential constraints include:

-Scarcity of resources -Competition -Predation -Disease -Accident

Estuaries

bays or semi-enclosed bodies of brackish water that form where rivers enter the ocean

Coral Reefs

-aggregations of coral polyps (minute colonial animals) that live symbiotically with photosynthetic algae. -their calcium rich skeletons build up the reef. -found in shallow water as light must penetrate for algal photosynthesis

Deserts

-characterized by low moisture levels (less than 12 inches per year) and precipitation that is infrequent and unpredictable from year to year. -have wide daily and seasonal temperature fluctuations. -plants exhibit water conservation characteristics -many plants bloom and set seed only after spring rains.

Tropical Seasonal Rainforest

-characterized by wet and dry seasons with hot temperatures year round. -located in India, Australia, West Africa, South America -brown and dormant much of the year but become green during the rainy season

Mangroves may be totally lost because....

-coastal development -fragmentation from roads -pollution, sediment, nutrient runoff -uncontrolled recreation -natural disturbances (hurricanes) -projected sea level rise

Temperate Grasslands

-communities of grasses and seasonal herbaceous flowering plants -few trees due to inadequate rainfall -large daily and seasonal temperature fluctuations -thick organic soils -much are converted to farmland. -overgrazing has become a threat because it kills the plants and permits erosion to occur.

Temperate Rainforest

-cool , rainy forests -condensation in canopy provides moisture to understory -mild year-round temperatures and abundant rainfall -common biome for California redwoods - subjecting to intense logging

Chlorophyll Levels

-dark green to blue: have high biological activity -dark blue ocean: have low biological activity

Tropical Savannas and Grasslands

-grasslands with sparse tree cover are called savannas. -rainfall amounts do not support forests -dry season prone to fire -plants have deep, long-lived roots and other adaptations to survive drought, heat, and fire -many migratory grazers such as antelope, wildebeest, or bison thrive on new growth after fires

Tropical Rainforests

-humid regions in the tropics that support one of the most complex and biologically rich biomes. -located in South and Central America, Africa, and SE Asia -rainfall exceeds 80 inches per year and temperatures are warm to hot year round -up to 2/3 of all the species of terrestrial plants and animals live in tropical forests.

Taiga

-northernmost edge of boreal forest -extreme cold and short summers limit the growth rate of trees. -a tree that is 4 inches in diameter may be over 200 years old.

Thermal Vent Community

-not discovered until 1977 -great diversity -unusual because they rely on chemosystesis, not photosynthesis for energy -tube worms, mussels, and microbes adapt to survive extreme temps and intense water pressures -ex. Mariana's Trench

Marine Ecosystems

-oceans cover 3/4 of Earth's surface. -photosynthesis is carried out by algae or free floating plants (phytoplankton). -greatest amount of photosynthesis is near the coast where nutrients wash in. -organisms die and fall to sea floor where the nutrients are used in deep ocean ecosystems. Upwelling currents circulate nutrients from the ocean floor back to the surface.

Temperate Deciduous Forest

-temperate regions support lush summer plant growth when water is plentiful. -deciduous trees lose their leaves in winter as an adaptation to freezing temperatures. -eastern half of U.S. was covered with broad leaf deciduous forest when European settlers arrived. -now much of that was harvested for timber.

Tundra

-temperatures below freezing most of year -high altitudes, treeless

What is the single largest cause of biodiversity loss?

Conversion of habitat to human use

Source Habitat

birth rates are higher than death rates. Surplus individuals can migrate to new locations.

Sink Habitat

birth rates are less than death rates and the species would disappear if not replenished from a source.

Benthic

bottom (Hadal zone)

Population Crash

a rapid dieback in the population to a level below the carrying capacity.

Atoll

a ring-shaped coral reef or a string of coral islands enclosing a shallow lagoon

Vertical Zonation

a term applied to vegetation zones defined by altitude

Ecological Diseases

animal epidemics -white nose syndrome in bats -herpes 1 virus in sea lions -imported fungus killing oaks, redwoods and Douglas fir woods in CA -dermo a parasite in oysters

Mangroves

are trees that grow in saltwater along tropical coastlines -help stabilize shoreline -nurseries for fish, shrimp -can be cut for timber -ex. Florida

Littoral zone

area near shore