Plants2_IntroPlants Spring 2025

Importance of Plants

• Ecological Significance: Plants play critical roles in ecological processes, nutrient cycling, and carbon management.

• Photoautotrophs:

  • Meaning: "photo" (light) + "autotroph" (self-feeder).

  • Functions:

    • Balance atmospheric gases

    • Ameliorate pollution

    • Supply oxygen (O2) for respiration.

  • Major link in the carbon, water, and nutrient cycles.

Key Roles in Ecosystems

• Plants are the base of the food chain and the primary source of food for all heterotrophic life forms, including humans.

• They convert atmospheric carbon (CO2) into organic matter, contributing to the Global Carbon Cycle:

  • Estimated carbon pools and annual fluxes among compartments crucial for climate stability.

  • Plants mitigate greenhouse gas effects by absorbing CO2 and releasing O2.

Aquatic Influences

• Aquatic Macroalgae and Phytoplankton:

  • Contribute to approximately 50% of global photosynthesis.

  • Play a significant role in the oceanic carbon cycle through photosynthesis and organic matter production.

• Biological Carbon Pump:

  • Phytoplankton play a crucial role in the ocean ecosystem and carbon storage through sedimentation.

Fossil Fuels

• Formed from plant remains during the Carboniferous period, which underwent significant transformation into coal over millions of years.

• Coal Formation Process:

  • Accumulation of dead plant material in marshy environments.

  • Partial decay producing peat, which can transform into coal when subjected to pressure and heat.

Medicinal Significance

• Plants also impact human health, with studies indicating that urban trees improve health outcomes in communities, particularly regarding cardiovascular and respiratory diseases.

Ecological Importance of Plants

• Plants as Photoautotrophs:

  • Balance atmospheric gases and participate in global carbon and nutrient cycles.

  • Fix carbon dioxide into organic matter for food sources of heterotrophs.

• Ecosystem Foundations:

  • Form the basis of habitats, influencing the organisms that live alongside them, which is reflected in biome classifications based on dominant plant types.

Understanding Biomes

• Biome Definition: Major community types characterized by dominant vegetation and plant adaptations to specific environments (climate influences).

• Major Types of Biomes:

  • Aquatic

  • Deserts

  • Forests

  • Grasslands

  • Tundra

• Terrestrial Biomes Influences:

  • Climate, geography (e.g., temperature, rainfall, altitude), geology, and human activities.

Plant Adaptations by Biome

• Desert Plants:

  • Have adaptations such as reduced leaves and water-storing capabilities (xerophytes).

• Tropical Forests:

  • Features include diverse life forms like epiphytes and lianas, adapted to compete for light.

• Savanna:

  • Characterized by open grassy plains and drought-resistant flora, trees that minimize transpiration with thick bark and small leaves.

Distinct Biomes and Their Features

• Tropical Rainforest:

  • Poor soils with rapid decomposition; species adapted for low light.

• Mediterranean (Chaparral):

  • Hot, dry summers and cool, wet winters; fire-adapted species.

• Taiga (Boreal Forest):

  • Characterized by conifers and seasonal CO2 fluctuation impacts.

• Tundra:

  • Permafrost regions with restricted plant life; effects of climate change under study.

Aquatic Biomes

• Types: Freshwater and estuarine ecosystems defined by water type, movement, and salinity.

• Key Aquatic Biomes:

  • Freshwater: Rivers and streams, ponds, and lakes (with distinct biotic zones).

  • Estuarine: Salt marshes and mangrove forests supporting diverse life and crucial nutrient cycling.

Marine Biomes

• Characteristics: Include intertidal zones, kelp forests, seagrass beds, and coral reefs, each with unique contributions to biodiversity and ecosystem health.