Ecology: Abiotic and Biotic Factors

Circulatory System Overview

• Vertebrates do not all have four-chambered hearts; fish possess only two chambers.
• Blood vessels are categorized into three types: arteries, veins, and capillaries, all having long and hollow structures.

Arteries

• Carry oxygenated blood from the heart to the body.
• Operate under high pressure; thicker walls resist pressure and maintain elasticity.
• Arteries branch into smaller arterioles, aiding blood distribution.

Veins

• Transport deoxygenated blood back to the heart, functioning under low pressure.
• Have thinner, non-elastic walls with wider lumens for easier blood flow.
• Muscle contractions compress veins, propelling blood; valves prevent backflow.

Capillaries

• Microscopic vessels facilitating the exchange of substances between blood and tissues.
• Comprise a single layer for efficient diffusion; structures slow blood flow for optimal exchange.
• Connect to form venules, leading back to veins.

Lymphatic System

• Comprises tissues and organs that eliminate toxins and waste.
• Primarily transports lymph, which contains white blood cells for immune defense.

Blood Components

• Main transport medium, carrying nutrients, wastes, and gases throughout the body.
• Red blood cells (erythrocytes) transport oxygen; originate from bone marrow and lack a nucleus for more hemoglobin capacity.

Abiotic and Biotic Factors

• Abiotic factors influence aquatic environments: water flow, salinity, oxygen availability, light, temperature, and pressure.
• Terrestrial factors include wind exposure, soil type, temperature, and water/light availability.
• Biotic factors encompass food availability, disease presence, population dynamics, and predation.

Selection Pressure in Ecosystems

• Selection pressures dictate survival changes within ecosystems.
• Natural selection favors species that adapt traits for survival, passing these traits to subsequent generations.
• Genetic diversity is crucial for adaptability; organisms with similar genomes struggle to survive under environmental pressures.

Ecology

• Focuses on relationships between living organisms and their environments.
• Factors influencing flora and fauna distribution and abundance include both abiotic and biotic elements.

Biological Diversity

• Encompasses genetic, species, and ecosystem diversity, promoting adaptability.
• Higher genetic diversity increases survivability in changing environments.

Natural Selection Concepts

• Organisms must possess advantageous traits for survival; diverse variations are crucial for long-term resilience.
• Overproduction leads to competition, where only those with suitable traits thrive.

Evolutionary Development

• Evolutionary diversification progressed from unicellular to multicellular organisms, influencing the rise of various life forms.
• Selection pressures have historically fostered species flourishing and extinction cycles.

Macroevolution vs. Microevolution

• Macroevolution occurs over extended periods, often leading to new species.
• Microevolution results in changes within a species without creating new ones.

Convergent and Divergent Evolution

• Convergent evolution: unrelated species evolving similar traits due to similar environmental pressures.
• Divergent evolution: ancestral species adapting differently due to varied selection pressures.

Gradualism vs. Punctuated Equilibrium

• Gradualism posits slow changes accumulating in populations over time, suggesting transitional forms.
• Punctuated equilibrium proposes rapid changes followed by stability, emphasizing bursts of evolution.

Evolution of the Platypus

• Exhibits features akin to birds and reptiles, demonstrating unique adaptations like electroreception.
• Represents macroevolution, primarily arising from ancestral lineages of mammals and reptiles.

Evidence of Evolution

• Evolution requires substantial time for significant species changes.
• Historical observations by Lamarck, Darwin, and Wallace highlighted similarities across species, now supported by genetic insights.
• Biochemical analysis shows that closely related organisms share macromolecules and reproductive processes.

Biotic Interactions

• Organism populations influence one another through various interactions, including predation and competition.
• Population dynamics can fluctuate due to resource availability and community size.

Competition in Ecology

• Competitors vie for limited resources, with varying outcomes over time.
• Competition can occur within a species (intraspecific) or between different species (interspecific), impacting survival strategies and population dynamics.

Test your knowledge on the different abiotic and biotic factors that influence both aquatic and terrestrial environments. This quiz covers aspects such as water flow rates, soil types, temperature ranges, and the various organisms within these ecosystems. Engage with key concepts that shape our natural world.