Ecology Biotic and Abiotic Components

Biotic and Abiotic Components of Ecosystems

• Biotic components include producers, consumers, and decomposers that influence populations and environments.
• Abiotic components are non-living factors, such as water, atmosphere, temperature, soil, sunlight, and wind, impacting living organisms and ecosystem functionality.

Habitat and Niche

• Habitat is the physical location where organisms reside.
• Niche encompasses all resources required for survival, growth, and reproduction.

Terrestrial Biomes

• Biomes are ecosystems with distinctive communities, shaped by variations in light, temperature, and moisture.

Temperate Deciduous Forest

• Characterized by warm summers, cool winters, and reliable rainfall, supporting large trees.
• Features broadleaf deciduous trees that shed leaves in winter and regrow in spring.

Polar Ice

• Coldest biome, including barren landscapes, glaciers, and ice sheets.
• Nunataks are ice-free areas that support flora, while marine algae (phytoplankton) serve as primary producers.

Tundra

• Defined by extreme cold and low precipitation, although water evaporates slowly, retaining moisture.
• Home to wildlife with adaptations for cold, including thick fur and permafrost, which is a permanently frozen layer beneath the surface.

Chaparral

• Also known as Mediterranean shrubland; characterized by mild, rainy winters and hot, dry summers.
• Subject to environmental stresses, including aridity and short growing seasons.

Taiga

• Largest terrestrial biome, also called northern coniferous forest or boreal forest, found in temperate latitudes.
• Soil is typically thin, nutrient-poor, and acidic; the biome supports abundant evergreen trees.

Temperate Rainforest

• Ecosystem characterized by high rainfall and mild temperatures.

Evolution of Human Traits

• Encephalization: Increased brain size linked to a diet of meat, starches, and cooking, essential for managing complex social issues.
• Skeletal changes include angular femur and robust knee and ankle joints for weight support and improved mobility.

Ulnar Opposition

• Unique to genus Homo; thumb opposition enhances grip strength and precision.
• Visual acuity becomes more significant compared to olfactory senses.

Sexual Dimorphism

• Refers to distinct characteristics between sexes of the same species beyond reproductive organs.
• Evolutionary changes include prolonged infant dependency and altered body plan (e.g., parabolic dental arcade and the presence of a chin).

Human Ancestry and Population Dynamics

• Recent ancestry includes gracile and robust Australopithecines with small braincases and bipedal locomotion.
• Demography studies key population metrics such as density (individuals per area) and dispersion (distribution patterns).

Modern Humans

• Demonstrated reduced sexual dimorphism and smaller jaw structures, allowing larger brain capacity.
• Population studies consider mortality patterns and age distributions.