Ecosystem Nutrient Cycling and Global Biodiversity Conservation
Nutrient Cycling and Ecosystem Dynamics
The Origin and Movement of Mineral Nitrogen (N)
Nutrients generally move among organisms. The **origin of mineral N** involves converting atmospheric N₂ into mineral forms (NH₄⁺, NO₃⁻) through:
- Biological fixation (by bacteria in roots or soil)
- Lightning fixation
- Industrial fixation (fertilizers)
N Cycling Steps:
- Plant uptake and incorporation (mineral → organic N)
- Resorption before leaf fall (retranslocating nutrients)
- Decomposition of litterfall (organic
Mammalian Adaptations: Locomotion, Metabolism, and Reproduction
L8 – Mammalian Locomotion I: Terrestrial Adaptations
- Cursorial: Running adaptation characterized by long limbs and reduced digits (e.g., pronghorn, cheetah).
- Advantages of Cursorial Locomotion: Increased range, successful migration, and endurance in predator–prey interactions.
- Cursorial Adaptations: Longer distal limbs, reduced or fused bones, and loss of the clavicle.
- Horse Evolution: Extreme digit reduction resulting in a single toe, optimizing efficient endurance.
- Ricochetal: Bipedal hopping utilizing
Core Concepts of Life Science and Biology Fundamentals
Photosynthesis: The Process of Life
- Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (light + chlorophyll)
- Location: In chloroplasts (mainly leaf cells).
- Purpose: Converts light energy into chemical energy (glucose).
- Reactants: Carbon dioxide (from air), water (from roots).
- Products: Glucose (used/stored), oxygen (released).
- Uses of Glucose:
- Respiration (energy)
- Stored as starch
- Cellulose (cell walls)
- Fats and oils (seeds)
- Proteins (with nitrates)
- Limiting Factors: Light intensity, temperature, CO₂ concentration,
Fundamentals of Biology: Cells, Tissues, and Organ Systems
Seven Characteristics of Life
- All living things are highly organized entities composed of one or more cells.
- Use energy for their metabolic activities.
- Respond to environmental stimuli.
- Regulate the internal environment to maintain relatively constant internal conditions (homeostasis).
- Grow and develop.
- Pass genetic material through reproduction.
- Adapt to their environment through evolution.
Biological Levels of Organization
- Cell (e.g., human blood cell)
- Tissue (e.g., human skin tissue)
- Organ and Organ System
Prostaglandins: Synthesis, Functions, and Clinical Roles
Introduction to Prostaglandins
Prostaglandins are a group of physiologically active lipid compounds that have diverse, hormone-like effects in animals. Unlike classical hormones, they are not secreted from a gland and do not travel to a distant site but are synthesized at the site where they are needed.
Discovered by: Ulf von Euler in 1935 in human semen, who thought they originated from the prostate gland (hence the name).
Classification: Prostaglandins belong to a broader group of bioactive lipids
Microbial Hydrocarbon Cleanup: Bioremediation Techniques
Microbial Biodegradation of Hydrocarbons
Hydrocarbons are major constituents of crude oil and petroleum. They can be biodegraded by naturally occurring microorganisms in freshwater and marine environments under a variety of aerobic and anaerobic conditions.
The Role of Microbes in Bioremediation
The ability of microorganisms—including bacteria, archaea, fungi, and algae—to break down hydrocarbons is the fundamental basis for both natural attenuation and enhanced bioremediation efforts.