Sensory Ecology

Sunlight Effects on Nature

  • Amount of Sunlight:

    • Affects day length.

    • Variability in day length is caused by the Tilt of the Earth, which creates different lengths of day over time and space.

Temperature Effects on Nature

  • Temperature:

    • The curvature of the Earth leads to variations in temperature across different regions.

Moisture and Its Impact

  • Moisture:

    • Hadley Cells are generated by hot rising air at the equator.

    • These cells create predictable areas of precipitation, contributing to the formation of deserts and wet areas.

Wind Formation

  • Wind:

    • Caused by temperature differences and the Earth's rotation.

Abiotic Factors in Ecology

  • Four main abiotic factors that impact the distribution and abundance of life on Earth:

    • Sunlight

    • Temperature

    • Moisture

    • Wind

Geography and Abiotic Factors

  • Geographical point of interest:

    • Areas at 30° North and South latitude are predisposed to:

    • A: Rising air currents and desert conditions.

    • B: Falling air currents and desert conditions.

    • C: Rising air currents and high levels of precipitation.

    • D: Falling air currents and high levels of precipitation.

Learning Objectives - Introduction to Ecology

  • Objectives of the study:

    • Define Ecology and its primary objectives.

    • Compare ecology across different levels of organization.

    • Explain the influence of biotic (living) and abiotic (non-living) factors on species distribution and abundance.

    • Define niche and niche differentiation.

    • Describe the four principal abiotic factors affecting life distribution and why they vary globally.

    • Explain the causes of seasons and predict seasonal changes based on the sun's position in Earth's orbit.

    • Describe how uneven heating of Earth's surface influences global water circulation and the distribution of terrestrial biomes.

Ecology & Global Environmental Problems

  • The lens of ecology offers insights into:

    • Major environmental challenges, illustrated by two examples.

Example 1: Wetland Ecosystems

  • Estimated coverage: More than 1,280 million hectares worldwide.

Geography of Wetlands

  • Specific locations:

    • Maryland

    • Virginia

    • Chincoteague Bay

    • Assateague Island

    • Atlantic Ocean

  • Wetland Ecosystems Importance:

    • Support habitat for up to half of North America’s bird species.

    • Approximately 27,000 species of insects have an aquatic phase in their lifecycle.

    • Estimated 30-40% of all amphibian species possess aquatic larval stages.

Migratory Spawning and Nursery Designated Use

  • Wetlands surrounding the Chesapeake Bay Estuary are designated for migratory spawning and nursery uses.

Biodiversity of the Bay

  • The Chesapeake Bay supports over 3,600 species of plant and animal life, including more than 300 fish species and 2,700 types of plants.

  • Species include:

    • Alewife Herring – Alosa pseudoharengus

    • Blue crab larvae – Callinectes sapidus

    • Juvenile Striped Bass – Morone saxatilis

    • Blueback Herring – Alosa aestivalis

Ecosystem Services Provided by Wetlands

  • Wetland ecosystems provide critical services, often referred to as "Nature's Kidneys":

    • Water purification

    • Flood protection

    • Shoreline erosion control

    • Recreation

Mechanism of Wetland Functions

  • How Wetlands Work:

    • Groundwater Flow: Filters contaminants, dissipating stream energy and sediment.

    • Stores and releases water slowly, providing critical wildlife habitat.

    • Bacteria and other organisms break down contaminants, enhancing water quality.

Loss of Wetland Acreage

  • Wetlands across the U.S. have suffered significant losses from the 1780s to the 1980s:

    • Many states have lost over 50% of their original wetlands.

    • Seven states (Indiana, Illinois, Missouri, Kentucky, Iowa, California, and Ohio) have lost over 80%.

    • Extensive losses since the 1970s particularly in Louisiana, Mississippi, Arkansas, Florida, South Carolina, and North Carolina.

  • Source: Mitch and Gosselink, Wetlands, 2nd Edition.

Causes of Wetland Loss

  • Human activities contributing to wetland loss include:

    • Draining for agriculture

    • Industrial mining

    • Channelization of water bodies:

    • Results in controlled flooding, diminished natural inundation, 60% wetland drainage, and reduced diversity of plants, fish, and waterfowl.

  • Initiatives began immediately aimed at restoring affected ecosystems.

Example 2: Coral Reefs

  • Coral reefs cover only 0.01% of the ocean floor but support 25% of all marine life.

Threats to Coral Reef Ecosystems

  • Factors threatening coral reefs globally include:

    • Overfishing: Alters ecosystem balance and removes herbivorous fish essential for algae control on corals.

    • Sedimentation: From land runoff negatively impacts water clarity and coral health.

    • Nutrient pollution: Treated poorly from agricultural runoff and human waste.

    • Global warming: Affecting temperature and causing ocean acidification, which reduces coral calcification.

Coral Reef Loss Data

  • Loss statistics around the globe:

    • Middle East: over 35% loss

    • Wider Indian Ocean: over 60% loss

    • Southeast and East Asia: over 35% loss

    • Caribbean/Atlantic Region: over 22% loss

Importance of Coral Reefs

  • An estimated 1 billion people benefit directly or indirectly from coral reef ecosystem services, including:

    • Sources of food and livelihood.

    • Protection against wave energy and shoreline erosion.

    • Attraction of tourism.

    • Potential for pharmaceutical developments.

Global CO2 Levels and Implications

  • CO2 levels monitored by government scientists at Mauna Loa Observatory indicate worrying trends:

    • September 2024: 422.03 ppm

    • September 2023: 418.51 ppm

  • Consistent increase in CO2 levels correlates with coral reef health deterioration.

Coral Bleaching and Climate Change

  • Mechanism of Coral Bleaching:

    • Warm water causes corals to expel endosymbiotic algae, turning corals white.

Recent Coral Reef Events

  • 2015-2016 marked one of the worst coral bleaching events on record, particularly affecting the Great Barrier Reef.

  • Reviews in 2020 indicated the Great Barrier Reef further deteriorated with widespread bleaching due to climate change.

  • In 2024, it was reported that 77% of global coral areas experienced bleaching-level heat stress.

Potential for Coral Regrowth

  • Despite decline, it has been shown that coral reefs can regrow in about 4 years under certain conditions, providing some hope for restoration efforts.

Community Action for Coral Reefs

  • Advocacy measures for coral health include:

    • Engaging in local and national electoral processes.

    • Volunteering for organizations like Greenpeace.

    • Educating oneself and others on ecological issues.

Learning Objectives - Sensory Ecology

  • Key focuses include:

    • How sensory organs gather and transmit information to the brain.

    • Basic functioning of the visual, chemosensory, and mechanosensory systems.

    • Comparison of sensory modalities under differing environmental conditions.

Sensory Ecology Defined

  • The study of how organisms acquire, process, and utilize sensory information to respond to ecological stimuli and navigate challenges.