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

  1. Habitat and Location

  2. Human-Induced Threats

  3. Consequences and Current Status

  4. Conservation Strategies

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