ENVS200-wk3.2-speciesinteractions

Species Interactions in Ecosystems

Overview of Course Content

• Course Title: Species Interactions ENVS 200

Student Learning Objectives

• By the end of the class, students will be able to:

  • Explain various ways in which species compete within an ecosystem.

  • Describe predator-prey interactions.

  • Understand the importance of biodiversity and the types of diversity.

  • Differentiate between the major biomes on Earth.

  • Discuss human impacts on biodiversity.

Trophic Levels and Food Consumption

Eating at a Lower Trophic Level

• Examples of Food Choices by a Farmer:

  • Hens:

    • Soy required: 99,918 kg

    • Water required: 1,498,770 gallons

    • Land required: 83.27 acres

    • Pesticides required: 4,996.2 kg

    • CO2 emitted: 4,163.5 kg

  • Grasshoppers:

    • Soy required: 6,570 kg

    • Water required: 98,550 gallons

    • Land required: 5.475 acres

    • Pesticides required: 328.5 kg

    • CO2 emitted: 273.75 kg

  • Soy:

    • Soy required: 243 kg

    • Water required: 3,645 gallons

    • Land required: 0.202 acres

    • Pesticides required: 12.12 kg

    • CO2 emitted: 10.1 kg

Interactions Among Species

Types of Species Interactions

• Five Main Types of Interactions:

  • Interspecific competition

  • Resource partitioning

  • Predation

  • Parasitism

  • Mutualism

  • Commensalism

• All interactions affect resource use and population sizes.

Competition

• Definition:

  • Competition occurs when two species vie for the same resource.

• Common Resources Competed:

  • Food

  • Shelter

  • Space

Resource Partitioning

• Definition:

  • Competing species evolve specialized traits that allow them to utilize shared resources at different times, in different ways, or in different locations.

Predation

• Definition:

  • Interaction where one species (predator) feeds directly on another (prey).

  • This relationship significantly affects population sizes.

How Predators Capture Prey

• Methods Utilized by Carnivores:

  • Running and flying

  • Coordinated pack hunting

  • Ambush strategies

  • Camouflage to sneak up on prey

  • Chemical warfare (e.g., poison)

How Prey Avoid Predators

• Strategies Employed by Prey:

  • Speed (running, swimming, flying fast)

  • Highly developed senses (e.g., sight, hearing)

  • Physical protection (e.g., shells, spines)

  • Camouflage (blending in with surroundings)

  • Chemical warfare (producing toxins)

  • Mimicry (imitating other organisms)

  • Behavioral strategies (e.g., fleeing, hiding)

Symbiotic Relationships

Parasitism

• Definition:

  • Relationship where one species (parasite) benefits at the expense of another (host), often living on or in the host.

Mutualism

• Definition:

  • Interaction where two species benefit each other, providing food, shelter, and protection.

Commensalism

• Definition:

  • Interaction where one species benefits while the other is neither helped nor harmed.

Biodiversity

Definition and Importance

• Biodiversity:

  • The variety of life within a specific area or ecosystem.

  • Essential for sustaining life on Earth; critical component of natural capital.

Types of Biodiversity

• Categories of Diversity:

  • Genetic diversity

  • Species diversity

  • Ecological diversity

  • Functional diversity

Major Ecosystems (Biomes)

• Examples:

  • Deserts, grasslands, forests, mountains, oceans, lakes, rivers, wetlands.

• Characteristics:

  • Biomes have distinct climates and species.

Human Impact on Biodiversity

Factors Influencing Biodiversity

• Balance between Speciation and Extinction:

  • Influenced by environmental changes and habitat degradation.

• Human Activities:

  • Cause loss of biodiversity through habitat destruction, pollution, and resource overexploitation.

Genetic Engineering and Biodiversity

• Artificial Selection:

  • Breeding plants or animals for desired traits, which differs from natural evolution.

• Genetic Manipulation:

  • Directly altering genes for specific traits and enabling gene transfer between species.

Keystone Species

Definition and Importance

• Definition:

  • Keystone species have a crucial role in defining ecosystem structures; their removal leads to significant changes.

• Characteristics:

  • Low functional redundancy, unique contributions to the ecosystem.

Examples and Impact

• Example of a Keystone Species:

  • Wolves in Yellowstone National Park.

    • Help control elk populations, impacting vegetation and overall ecosystem health.

• Consequences of Removal:

  • Trophic cascade leading to overpopulation of elk, overgrazing, and subsequent ecological damage.

Ecosystem Responses to Environmental Changes

Types of Ecological Succession

• Primary Succession:

  • Establishment of biotic communities in lifeless areas without soil.

• Secondary Succession:

  • Recovery in disturbed ecosystems where soil remains, promoting biodiversity and ecosystem complexity.

Importance of Succession

• Enhances interactions among species, increases nutrient cycling, and supports overall ecosystem health.