UNIT 2: ECOLOGYTHE BIOSPHERE

Apollo 8 December 24, 1968

“Ecology”?

= The study of interactions among organisms and between organisms and their environment

Levels of Ecology:

SpeciesPopulations

Communities

Ecosystems

BiomesBiosphere

Put these in order (smallest largest)

Biosphere8km Up11km Down

At the core of every organism’s interaction with the environment is its need for energy to power life’s processes

The flow of energy through an ecosystem is one of the most important factors that determines the system’s capacity to sustain life

“Autotrophs” “Heterotrophs”

MainSource

Autotrophs/ Producers (Photosynthetic and Chemosynthetic)

Heterotrophs/Consumers (Herb-/Carn-/Omn-ivores and Decomposers)

Energy flows through an ecosystem in one direction, Sun or Inorganic compounds Autotrophs (producers) Heterotrophs (consumers)

Food Chains = a series of steps in which organisms transfer energy by eating and being eaten

Trophic Levels = each step in a food chain or food web

Food Webs = links all the food chains in an ecosystem together

Producers?First Order/Primary Consumers?Second Order/Secondary Consumers?Third Order/Tertiary Consumers?Fourth Order/Quaternary Consumers?

Ecological Pyramid = a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web

Energy Pyramids = represents the amount of energy that is transferred from one trophic level to the next

Only about 10% of the energy available within one trophic level is transferred to the next

What happens to the rest?Life Processes and Heat

Biomass Pyramids = represent the amount of potential food that is available for each trophic level in an ecosystem

Biomass is usually expressed in terms of grams of organic (living) matter per unit area

Pyramid of Numbers = represents the numbers of individual organisms at each trophic level in an ecosystem

Cycles

Don’t just need energy!

What else is needed?

More than 95% of the body is made up of just four elements: oxygen, carbon, hydrogen, and nitrogen

Biogeochemical Cycles

Organisms don’t “use-up” matter,they “transform” it

The Water Cycle

The Carbon CycleNutrient Cycles

The Nitrogen CycleProteins

Nitrogen Fixation

78%

The Phosphorous CycleDNA/ RNA/ ATP

Doesn’t enter the atmosphere

Primary Productivity = the rate at which organic matter is created by producers

Limiting Nutrient = a nutrient that is scarce or cycle slowly

Oceans = Nitrogen

UNIT 2: ECOLOGYECOSYSTEMS

ANDCOMMUNITIES

1. The Role of the Climate2. What Shapes an Ecosystem?3. Biomes4. Aquatic Ecosystems

1. THE ROLE OF CLIMATE

• What is Climate?

• The Greenhouse Effect

• The Effect of Latitude on Climate

• Heat Transport in the Biosphere

What is Climate?

Weather = the day-to-day conditionof Earth’s atmosphere at a particulartime and place.

Climate = the average, year-after-year conditions of temperature and precipitation in a particular region.

What factors affect the climate?

The Greenhouse EffectGreenhouse Effect = the natural situation in which heat is retained by greenhouse gases (warming effect)

Carbon dioxide, methane, water vapor, and a few other atmospheric gases

Earth would be 30o C cooler than it is today if these gases weren’t present

The Effect of Latitude on ClimateEarth’s 23.5o tilt on its axis causes different parts of Earth to receive different angles of solar radiation

This results in a difference in heat distribution with latitude

Three Main Climate Zones

Temperate Zones = sit between the polar and tropical zones

Tropical Zones = between 23.5o North and 23.5o South of the Equator

Polar Zones = between 66.5o and 90o North and South latitudes

PolarZones

Low Angle SunlightCold

TemperateZones

SeasonalChanging Angle

TropicalZones

Direct AngleConstant

Warm “Rises”Pole-ward

Cold “Sinks”Equator-ward

The unequal heating of Earth’s surface drives winds and ocean currents, which transport heat throughout the biosphere

Heat Transport in the Biosphere

Winds Ocean Currents

Ocean Currents contribute for same reasonsMountains and the ”Rain Shadow” Effect

2. WHAT SHAPES AN ECOSYSTEM?

• Biotic and Abiotic Factors

• The Niche

• Community Interactions

• Ecological Succession

Biotic and Abiotic FactorsBiotic Factors = the biological influences on organisms within an ecosystem Abiotic Factors = physical, or nonliving factors that shape ecosystems

Determine the survival and growth of an organisms and the productivity of the ecosystem in which the organism lives

Habitat = the area where an organism lives (includes both biotic and abiotic factors)

The NicheNiche = the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions

Community InteractionsCommunity interactions can powerfully affect an ecosystem

Competition occurs when organisms of the same or different species attempt to use an ecological “resource” in the same place at the same time

Often results in a winner and a loser (fails to survive)

1. Competition

Competitive Exclusion Principle = no two species can occupy the same niche in the same habitat at the same time

CEP is a fundamental rule in ecology

Predation = an interaction in which one organism captures and feeds on another organism (predator/ prey)

2. Predation

Symbiosis = any relationship in which two species live closely together (“living together”)

3. Symbiosis

A. MutualismB. CommensalismC. Parasitism

A. Mutualism = both species benefit from the relationship

B. Commensalism = one member benefits and the other is neither helped nor harmed

C. Parasitism = one organism lives on or inside another organism (the host) and harms it

Ecosystems and communities are always changing (abruptly or gradually) in response to natural or human disturbances

Ecological Succession = this series of predictable changes that occurs in a community over time

Ecological Succession

Lowered to 8,363 ft

Summit = 9,677 ft

Mt. St. Helens May 1980

As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community

Primary Succession = succession (on land) that occurs on surfaces where no soil exists (volcanic eruptions, glaciers, etc.)

Pioneer Species = the first species to populate the area

Lichen = a symbiotic relationship between a fungus and an algae (protist)

Enchanted Rock (Fredericksburg)

Secondary Succession = succession that occurs when a disturbance of some kind changes an existing community without removing the soil

Succession can even occur at the bottom of the oceans

3. BIOMES

• Biomes and Climate

• The Major Biomes

• Other Land Areas

Ecologists group Earth’s diverse environments into biomes

Biome = a complex of terrestrial communities that covers a large area and is characterized by certain soil and climate conditions and particular assemblages of plants and animals

World’s Major Biomes:-Tropical Rain Forest-Tropical Dry Forest-Tropical Savanna-Desert-Temperate Grassland-Temperate Woodland and Shrubland-Temperate Forest-Northwestern Coniferous Forest-Boreal Forest

-Tundra

Each of these biomes is defined by a unique set of abiotic factors – particularly climate- and a characteristic assemblage of plants and animals

Adaptations Tolerance

Microclimate = the climate in a small area that differs from the climate around it

The climate of a region is an important factor in determining which organisms can survive there

Some areas of land on Earth do not fall neatly into the major biome categories

Mountain Ranges

Abiotic and biotic conditions vary with elevation

Polar Ice Caps

North Polar Region (thinner ice)South Polar Region (thicker ice)

4. AQUATIC ECOSYSTEMS

DepthFlowTempChemistry of Water

Impacted by:

Freshwater Ecosystems3% of World’s Surface Water

Standing-Water

Flowing-Water

Flowing-Water Ecosystems:(Rivers, Steams, Creeks, and Brooks)

Typically originate in mountains or hills, often springing from an underground water source

Plenty of dissolved oxygen but little plant life

As the water flows downhill, sediments build up and enable plants to establish themselves

Farther downstream, the water may meander more slowly through flat areas

Standing-Water Ecosystems: Lakes and ponds

In addition to the net flow of water in and out of these systems, there is usually water circulating (turning-over) within them

This circulation helps to distribute heat, oxygen, and nutrients

Phytoplankton = single-celled algae supported by nutrients in the water

Zooplankton = planktonic animals that feed on the phytoplankton

Plankton = tiny, free-floating or weakly swimming organisms that live in both fresh/saltwater

Freshwater Wetlands:

Wetland = an ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year

“Biodiversity”

Bog

Swamp

Marsh

Estuaries = are wetlands formed where rivers meet the sea

Estuaries

fresh water and salt water (brackish) Affected by the ocean tides

HighProductivity

Detritus = is made up of tiny pieces of organic material that provide food for organisms at the base of the estuary’s food web

Photosynthesis(200 meters)

Chemosynthesis

“Coastal Zone” “Open Ocean”

Coral Reefs Exists in warm, shallow water of tropical coastal oceans

Among the most diverse and productive environments on Earth

Named for the coral animals whose hard, calcium carbonate skeletons make up their primary structure (Coral)

Symbiotic relationship with Algae

Algae: PhotosynthesisCoral: Waste