Lecture #08 – Ecosystems(1)
Page 1: Course Overview
Course Title and Module
Environmental Science and Sustainability
Course Code: GEOG 280
Module #4
Instructor: Dr. Giliane Rasbold
Contact: giliane.rasbold@wku.edu
Institution: WKU Department of Earth, Environmental, and Atmospheric Sciences
Page 2: Organization of the Environment (Ecology)
Definitions
Species
A group of living organisms capable of interbreeding and exchanging genes.
Population
A subset of individuals of one species occupying a specific geographic area.
Biological Community
An interacting group of various species in a common location.
Page 3: Ecosystem Organization
Ecosystem Definition
A biological community of interacting organisms and their physical environment, encompassing both biotic (living) and abiotic (non-living) factors.
Energy and Matter Flow
Describes the flow of energy and cycling of matter among organisms and their environment.
Types of Ecosystems
Aquatic Ecosystems: Freshwater, Marine
Terrestrial Ecosystems
Page 4: Freshwater Aquatic Ecosystems
Abiotic Factors Affecting Life
Water temperature
Amount of sunlight
Oxygen levels in water
Nutrient availability
Water movement
Examples of Freshwater Ecosystems
Lakes, ponds, wetlands, rivers
Page 5: Marine Ecosystems
Abiotic Factors Affecting Life
Light availability (photic and aphotic zones)
Temperature
Depth
Distance from shore (Benthic vs. Pelagic zones)
Page 6: Wetlands
Definition
Areas inundated or saturated by surface or groundwater, supporting vegetation adapted for life in saturated soil conditions, defined by U.S. regulations since the 1970s.
Page 7: Functions of Freshwater Wetlands
Key Functions
Absorb and remove pollutants from water (functioning like kidneys in the landscape)
Control flooding and stream flow rates
Serve as nurseries for biodiversity (hotspots)
Recreational spaces
Characteristics of Wetland Soils and Vegetation
Hydric soils develop under anoxic conditions, noted by color and physical structure.
Hydric vegetation adapted to substrate inundation, affected by oxygen levels.
Page 8: Types of Wetland Ecosystems
Major Types
Swamps: Forested wetlands in tropical and temperate climates.
Marshes: Wetlands without trees.
Bogs: Characterized by cooler climates.
Page 9: Ecotones
Definition and Importance
Transitional zones between distinct ecosystems.
Higher species diversity due to the overlap of ecological niches.
Page 10: Ecosystem Services
Benefits from Ecosystems
Provisioning Services: Food, clean water, wood, and pollination.
Regulating Services: Climate regulation, flood control, and water purification.
Cultural Services: Aesthetic, recreational, and educational values.
Supporting Services: Soil formation, photosynthesis, and biodiversity maintenance.
Page 11: Landscapes
Definition
A cluster of interacting ecosystems representing a specific geographical area.
Page 12: Biomes
Definition
Large geographical areas classified by temperature, precipitation, and dominant vegetation types.
Biomes share similar climate, soil conditions, and comparable communities.
Influencing Factors
Latitude, altitude, and precipitation.
Page 13: Habitat and Niche
Habitat
The place where a species is adapted to live based on conditions and resources.
Niche
The role a species plays in its habitat, including food sources, reproduction, and relationships with other species
Page 14: Limiting Factors
Population Dynamics
Limiting Factors
Operate within an optimum range, acting as environmental resistance.
Biotic Potential
Factors that increase population, like reproductive rates and adaptations.
Environmental Resistance
Challenges like lack of food, water, suitable habitats, predators, diseases, and competition.
Page 15: Optimum Range
Concept of Tolerance Ranges
Describes the conditions under which a species can thrive, including physiological stress zones and intolerable conditions.
Page 16: Keystone Species
Definition
A species on which other ecosystem members heavily depend; its removal alters the ecosystem significantly.
Types of Roles
Predator, Prey, Ecosystem Engineer.
Page 17: Prey Role
Importance of Prey
Serves as a critical food source for predator populations.
Resilient and aids in maintaining predator-prey balance.
Page 18: Predator Role
Importance of Predators
Controls prey population and range; their removal can cause a trophic cascade.
Page 19: Trophic Cascade
Ecological Events
Top-Down: A change in predators triggers a chain reaction down the food web.
Bottom-Up: A change at the producer level affects the entire web.
Page 20: Ecosystem Engineers
Definition and Examples
Organisms that create or modify landscapes and influence the prevalence of other species.
Example: Beavers create ponds that offer habitats for other species, providing protection from predators.
Page 21: Indicator Species
Importance
Reflects environmental conditions, helping in monitoring ecological changes.
Examples
Amphibians (e.g., frogs) indicate pollution levels due to their sensitive skin.
Algae serve as indicators of water quality deterioration.
Page 22: Endemic Species
Definition and Examples
Species restricted to a specific geographical area, not found elsewhere.
Examples
Kangaroos in Australia, Lemurs in Madagascar, Poison dart frogs in Costa Rica.
Page 23: Invasive Species
Definition
Non-native species whose introduction can cause ecological harm.
Examples
Zebra mussels, Hydrilla, Asian Carp.
Page 24: Community Interactions - Competition
Types
Competition: Both species harmed (- -)
Interspecific competition (between species)
Intraspecific competition (within species)
Page 25: Community Interactions - Predation
Definition
One organism benefits at the expense of another (predator-prey relationship).
Example
Lions hunting zebras helps regulate both populations.
Page 26: Community Interactions - Mutualism
Definition
Both species benefit from the interaction.
Example
Bees pollinating flowers while feeding on nectar.
Page 27: Community Interactions - Parasitism
Definition
One organism benefits at the other's expense, causing harm (parasite-host relationship).
Example
Ticks feeding on dogs.
Page 28: Community Interactions - Amensalism
Definition
One species harmed while the other remains unaffected.
Example
A tree shading smaller plants.
Page 29: Community Interactions - Commensalism
Definition
One species benefits while the other is neither helped nor harmed.
Example
Barnacles on whales.
Page 30: Reasons for Species Decline
Major Factors
Habitat change, conversion, fragmentation, simplification.
Overexploitation, pollution, invasive species, land management, and changing species interactions.
Page 31: Trophic Pyramid - Terrestrial System
Energy Transfer
Follows the 10% rule: Approximately 10% of energy/biomass is passed to the next level.
Example Breakdown
1,000 lbs of plants (producers) -> 100 lbs of herbivores (primary consumers) -> 10 lbs of carnivores (secondary consumers).
Page 32: Trophic Pyramid - Aquatic System
Energy Dynamics
Energy distribution may be reversed; higher trophic levels may contain more biomass than primary producers due to reproductive speed and energy efficiency.
Page 33: Bioaccumulation vs. Biomagnification
Definitions
Bioaccumulation: Contaminant accumulation in an organism over time from various sources.
Biomagnification: Increased toxin concentration in organisms higher up the food chain.
Page 34: Case Study: Mercury
Example
Mercury in predatory fish is a prominent example of biomagnification, leading to health risks for humans consuming these fish.
Page 35: Disturbance and Resilience
Resilience Definition
The ability of an ecosystem to return to normal after a disturbance.
Indicators of Resilience
Nutrient replenishment, plant and animal dispersion, regrowth, and succession.
Page 36: Forest Ecosystems
Types
Temperate Deciduous Forests: Characterized by hardwoods like oak and maple, found in the eastern U.S.
Coniferous Forests: Dominant in northern states and the Pacific, featuring evergreen trees.
Page 37: Aquatic and Coastal Ecosystems
Freshwater Ecosystems
Lakes and ponds are abundant, major river systems include the Mississippi and Colorado.
Marine Ecosystems
Include diverse ecosystems such as kelp forests, coral reefs, and crucial wetlands in coastal areas.
Page 38: Threatened Species Overview
Examined Species
Bighorn Sheep, Grizzly Bears, Woodland Caribou, Killer Whales, Manatees, Polar Bears, Jaguars.
Assessment Factors
Habitat and Location
Human-Induced Threats
Consequences and Current Status
Conservation Strategies