Abiotic Environmental Factors

Abiotic Influences (Non-living environmental factors)

• These are the physical and chemical parts of an environment.
• They dictate where and how different species can live.

Physical and Chemical Factors

• Temperature affects metabolic rates and enzyme activity.
• Survival is limited if it is too cold or too hot.
• Water availability is critical for all life.
• Plant growth and animal survival are limited by both drought and excess water (e.g., floods).
• Light affects both photosynthesis in plants and activity cycles in animals.
• Soil composition shapes what plants can grow.
• This in turn affects herbivores and predators.
• High salt concentrations (e.g., in estuaries or salt flats) can limit freshwater species.
• Certain organisms are harmed by acidic or alkaline soils/water.
• Wind affects transpiration in plants, pollination, and seed dispersal.

Adaptations to Extreme Abiotic Conditions

• Fish and insects use antifreeze proteins to combat freezing temperatures.
• Animals deal with freezing temperatures through hibernation or migration.
• Plants become dormant or produce seeds that survive winter.
• Cacti store water and reduce leaf area to deal with water scarcity.
• Desert animals are nocturnal and conserve water using efficient kidneys.
• Halophytes (e.g., mangroves) excrete salt or store it in vacuoles to deal with high salinity.
• Marine animals maintain osmotic balance through specialized organs such as salt glands.

Biotic Influences (Living environmental factors)

• Involve interactions with other organisms.
• Shapes where a species lives.

Species Interactions

• Competition (interspecific and intraspecific) occurs for limited resources like food, space, and light.
• Populations of prey can be reduced, or restricted to predator-free areas due to predation.
• Hosts can be excluded from habitats where parasites are common due to parasitism.
• A mutualist partner may be necessary.
• Examples are pollinators for plants and mycorrhizae for roots.
• One species makes the environment more suitable for another through facilitation .
• An example is shade from larger plants in deserts.

Dispersal Limitations

• Species may be absent from suitable habitats because they haven't reached them.
• Barriers like mountains, rivers, or human development can limit movement.
• Natural range expansion vs. human-assisted dispersal (invasives)

Local vs. Global Patterns

• Microhabitats and small changes in abiotic or biotic factors can shift distributions on a local scale.
• An example is the north vs. south side of a hill.
• Climate zones, continental drift, ocean currents, and latitude affect species ranges on a global scale.