Ecology: The study of living (biotic) and non-living (abiotic) components that interact within an ecosystem.
Abiotic factors: Non-living factors influencing organisms/system.
Example: Sunlight affects temperature and evaporation rates.
Levels of organization: Species → Population → Community → Ecosystem → Biome → Biosphere.
Ecosystem: A community of interdependent organisms and their physical environment.
Species: A group of organisms capable of reproducing and producing fertile offspring.
Scientific Names: Used to identify species scientifically (Genus species); always italicized or underlined.
Keystone Species: Crucial species for ecosystem maintenance, influencing structure and nature of ecosystems.
Example: Wolves in Yellowstone, beavers in rivers.
Niche: Specific role of an organism encompassing where, when, what, and how it lives.
Associated with trophic levels in ecosystems.
Example: Plants as primary producers, tigers in herbivore population control.
Niche Theory: No two species can occupy identical niches simultaneously to avoid competition.
Fundamental Niche: Range of conditions a species can live under.
Realized Niche: Actual conditions an organism lives under, often affected by competition.
Case Study: Joseph Connell's barnacles - comparing fundamental and realized niches.
Intraspecific competition: Competition between the same species, stabilizing population size and influencing phases of growth.
Predation: The act of hunting.
Herbivory: Consumption of plants.
Example: Rabbits eating grass.
Parasitism: One organism relies on another for nutrition, often harming the host.
Mutualism: Interaction where both species benefit.
Competition: Struggle for resources; can be intra-specific or inter-specific.
Amensalism: One species is harmed while another is unaffected.
Example: Cows and sheep in pasture; cows starve due to competition from sheep.
Neutralism: No significant relationship exists between organisms.
Competitive exclusion principle: No two species can occupy the same niche indefinitely in limiting resource conditions.
American Alligator: A keystone species that creates gator holes for refuge of aquatic species during dry seasons.
Pesticides: Man-made pollutants including herbicides, fungicides, and bactericides, designed to manage pests.
Bioaccumulation: Accumulation of substances (toxins) in an organism over time; organisms cannot eliminate them effectively.
Examples: DDT, Methyl Mercury; associated effects include cancer and birth defects.
DDT:
Benefits: Low toxicity for humans, effective against insects, inexpensive to produce.
Problems: Long environmental activity, causes shell thinning in birds.
Status: Banned in North America since the 1970s but still used in the Third World.
Biomagnification: Increasing concentration of toxins in organisms at higher trophic levels.
Ecological Pyramids: Represent numerical relationships between trophic levels in a community.
Choice of pyramid depends on data type/quantity collected.
The Second Law of Thermodynamics states energy decreases along food webs; thus, pyramids narrow as one ascends trophic levels.
Energy Loss: Approximately 90% lost at each level due to homeostasis, heat, and movement.
Pyramid of Biomass: Represents standing stock of each trophic level.
Pyramid of Productivity: Represents energy flow through trophic levels, always decreases as it ascends due to energy loss.
Solar Energy Fate: Measured in joules per second per square meter (J s -1 m-2).
Solar Constant: The rate of solar energy reaching the top of Earth’s atmosphere.
Productivity: Conversion of solar energy into biomass over time, measured per unit area.
Biomes: Collections of ecosystems sharing similar climatic conditions.
Biosphere: Portions of Earth inhabited by living organisms.
Aquatic Biomes: Freshwater and Marine; include swamps, rivers, coral reefs, and deep oceans.
Deserts: Characterized by hot and cold variations.
Forests: Tropical, Temperate, Boreal (Taiga).
Grasslands: Tropical, Temperate, Savanna.
Tundra: Arctic and Alpine types.
Climate: Major influencing factor regarding growth patterns, with geography also significant.
Factors: Temperature, precipitation, latitude, and altitude.
Characteristics: Hot and wet, high biodiversity.
Climate: Rainfall 2000-5000 mm/yr, average temperature 26-28 degrees Celsius.
Productivity: High net productivity; continuous growing season.
Characteristics: Dry, high daily temperature variation.
Climate: Less than 250 mm/yr precipitation.
Adaptations: Drought-resistant plants, small mammals.
Characteristics: Dominated by grasses, ideal for agriculture.
Climate Factors: Precipitation equals evaporation.
Biodiversity: Low compared to forests.
Characteristics: Mild climate, often deciduous.
Climate Factors: Rainfall 500-1500 mm/yr.
Characteristics: Cold, low biodiversity, thin soil.
Climate Factors: Low precipitation, permafrost present.
Characteristics: Covers 65% of Earth's surface, diverse environments from shallow to deep.
Light Limitation: Nutrient levels are low, leading to low primary productivity.
Succession: Ecosystem evolution over time.
Zonation: Ecosystem changes along gradients (e.g., altitude).
Primary Succession: Colonization of barren land; starts with pioneer species.
Stages: Colonization, Establishment, Competition, Stabilization.
Secondary Succession: Recovery of complex ecosystems after disturbance.
K-Strategists: Stable environments; longer-lived, fewer offspring.
R-Strategists: Unstable environments; short life cycles, rapid reproduction.
Survivorship Curves: Illustrates lifespan and mortality at various life stages.