ENVS 150 Final Notes

Soil

Soil

composed of weathered rock, air, water, decomposed organic material, and various organisms

Soil consists of…

• A solid fraction- rock fragments and minerals

• Organic fraction- decaying/decayed plant residue, microbes, and soil animals

• Liquid fraction- water and dissolved minerals

• Soil atmosphere/soil air

Pore space

voids between soil solids

Litter

Partially decayed organic matter on the surface

Humus

highly decomposed, fine, amorphous organic matter in soil

Soil texture

the percent of sand, silt, and clay particles in soil

Loam

a soil consisting of sand, silt, and clay

Major components of all organic compounds (~96%)

Oxygen (O), carbon (C), and hydrogen(H)

Macronutrients (~3.5%)

Nitrogen (N), potassium (K), and phosphorus(P)

Micronutrients (<1%)

Iron (Fe), Boron (B), Copper (Cu), and Zinc (Zn)

Mobile elements

• move both up and down the plant through the xylem and phloem

• Deficiency appears on older leaves first (N,P,K,Mg,S)

• Can be removed from one part of the plant to another

Immobile elements

• moves up the plant by only acropetal (in the xylem) transport

• Deficiency appears on new leaves first (Ca,Fe,Zn,Mo,B,Cu,M)

• Cannot be moved once they are incorporated into the plant

Plants require large amounts of _____ because it is found in all proteins

Nitrogen

What two forms of nitrogen can plants absorb?

Ammonium (NH4+) and Nitrate (NO3-)

Examples of nutrient deficiency in plants

• stunted growth

• weak stems

• deformed leaves

• Chlorosis

• necrosis

• dark green color

Nitrogen (N)

• Plants require a lot of this element

• also found in DNA and RNA

• most common deficient in plant growing systems

Phosphorus (P)

• present in energy-rich compounds - ATP and NADPH

• the second most limiting element for plant growth

• not abundant on earth

Potassium (K)

• critical for control of stomata opening and closing

• increases root growth and improves drought resistance

• retained in soil because of its positive charge

Water and mineral transport

• taken up in the roots

• transported within xylem

• roots→ stems→ leaves → atmosphere

• transpiration

• Cohesion-tension theory

Sugar transport

• produced in the source

• transported within phloem

• source→sink

• translocation

• pressure-flow hypothesis

Cohesion-tension theory

• High-to-low water potential.

• roots → leaves

Pressure flow hypothesis

How sugar moves in a plant. Flows through the phloem (flow-um)

Hadley cells

• moist areas and deserts

• between 0 and 30 degrees lat.

Cell

Global air circulation pattern

High specific heat

Water takes longer to lose heat

Climate

long-term weather conditions based on temperature, rainfall, humidity, and wind

Terrestrial biomes are defined by…

• 14 kinds of biomes

• rainfall

• plant communities

• temperature

Aquatic biomes are defined by…

• depth and water flow

• proximity to land

• organisms

• fresh/salt water

What two things have a predominate effect on biome distribution?

Temperature and precipitation

____ is the most important factor near poles

Temperature

____ is the most important factor in tropical and temperate biomes

Precipitation

Climate change effects….

• Plant distribution

• Flowering time

• Nitrogen availability

Arctic tundra

• Closest to the poles and not covered permanently with ice

• growing season- up to 3 months

• No trees

• low rainfall

Boreal forest

• South of Arctic tundra

• growing season- up to 4 months

• soil is acidic and mineral-poor

• fluctuating temperatures

Temperate coniferous forest (aka temperate rainforest)

• highly productive in coastal areas

• longer growing season

• higher rainfall

• mild winters, cool summers

• frequent fires

• sandy, nutrient-poor soil

Temperate broadleaf and mixed forest

• deciduous trees dominate but are also mixed with conifers

• warm summers, cold winters

• high rainfall

• rich topsoil

• mostly destroyed by logging and urbanization

Temperate grasslands

• few trees along the stream

• more than 90% turned into cropland

• North America’s rarest biome

• lots of grasses and some herbaceous plants

Chapparal

• Broadleaf (thorny) shrubs able to withstand long summer droughts

• mild, moist winters and hot,dry summers

• referred as having a “Mediterranean climate”

• wildfires common in late summer and autumn

Savannas

• Grasslands with trees spaced further apart

• Grass growing between trees

Shrublands

• Grasslands with shrubs widely spaced

• Grass grows between shrubs

Deserts and Xeric shrublands

• has the biggest desert- the Sahara desert

• cold nights, hot days

• plants used to little water and formed fit cuticles

• Low-growing plants with small leaves and spines for protection

• common plants: Joshua tree, cacti, agave

• threatened by human encroachment and environmental damage from off-road vehicles

Tropical and subtropical moist broadleaf forests

• high rainfall

• warm and moist year-round

• largest number of plants and animals

• also known as rainforests

• 3 layers of vegetation

• up to 300 tree species

• industrial expansion and human population growth threatens rainforests

r/K selection theory

developed in the 1960’s by MacAurthur and Wilson

r-selected populations

• fast maturation

• reproduction at early age

• large number of offspring

• low survival rate

• short lifespan

• poorly adapted to competition

K-selected population

• longer time to mature

• longer time to reproduce

• fewer offspring

• greater survival rate

• long lifespans

• adapted to competition

Conservation biology

Studies the environment and the species, their population and communities

Main goals of conservation biology

• understand why some species are declining or flourishing in numbers

• preserve threatened species

• restore their environments

• reduce fragmentation

Wetland’s important biological and ecological functions:

• prevent shoreline erosion

• provide an area to store water during floods

• acts as a natural water filter

• part of global water cycle

• important carbon sinks

Biogeochemical cycles

ecosystems constantly recycle water and elements like carbon, nitrogen, and phosphorus but nutrients may be lost to:

• leaching below the root zone

• erosion into streams

• volatilization into atmosphere

• human activities

The rate of nutrient cycling is determines by…

the rate of decomposition

Ecological succession

A slow process that occurs over long periods of time

2 types of succession:

• Primary succession

  • starts on new substrate (rock, mudflat, beach, etc.

• Secondary succession

  • starts on substrate within vegetation remnants (rhizomes, seeds, etc.)

Succession describes…

the gradual establishment of different species in a habitat

Clay (-) attracts..

positive cations

Cations

• positively charged

• bound to negative particles

• not easily absorbed by roots

• not subject to leaching

Anions

• negatively charges

• readily dissolve in water

• easily absorbed by roots

• subject to leaching

Translocation

• aka sugar transport

• source

  • where sugars enter the phloem

  • where sugars are made or stored

• sink

  • where sugars exit the phloem

  • where sugars are being used

Ecology

• studies the relationship and interaction between organisms and their environment

• distribution and quantity of organisms in certain environments

• factors limiting and supporting the population

Food chains are made up of..

• autotrophs (plants)

• primary consumers (eat plants)

• secondary consumers (eat primary consumers)

• tertiary consumers (eat secondary consumers)

Food webs

represents the interconnected food chains in an ecosystem

The longer the food chain is….

• The less energy is conserved

• each step loses 90% of the energy

high specific heat

the amount of heat required to raise the temp. of 1 gram if a substance by 1 degree C

rain shadow

dry backside of a mountain, located behind the ridge on the mountain where warm, moist air rises and rain is deposited before air crosses the ridge

chlorosis is ___ of the leaves

yellowing

mycorrhizal fungi helps the plan take up what element?

Phosphorus