Biotic and Abiotic Factors

Biotic Factors (living parts of an environment)

1. Availability of food

   • All animals rely on other organisms for food.

   • If food availability falls, the population of consumers also decreases.

2. New predators

   • Arrival of a new predator can reduce prey populations.

   • Can also affect existing predators due to competition for the same prey.

3. Competition between species

   • If a species is outcompeted, its population can drop, potentially to extinction.

4. New pathogens

   • Emergence of infectious diseases can wipe out populations.

Abiotic Factors (non-living parts of an environment)

1. Light intensity

   • Essential for photosynthesis in plants.

   • Low light → slower plant growth → less food for herbivores.

2. Temperature

   • Changes can affect species distribution.

   • Animals may migrate; plants may disappear if conditions are unsuitable.

3. Water availability

   • All organisms need water to survive.

   • Some species are adapted to low water levels.

4. Soil pH and mineral content

   • Soil must have suitable pH and minerals for plant growth (e.g., nitrate for proteins).

5. Wind intensity and direction

   • Can increase water loss in plants.

   • Plants in windy environments often have adaptations to reduce water loss.

6. Gases (CO₂ and O₂)

   • CO₂ needed for photosynthesis; low levels → slower growth.

   • O₂ needed for aerobic respiration; dissolved oxygen in water can drop on hot days, affecting aquatic life.

Key Concepts / Summary

• Biotic factors = living components affecting populations.

• Abiotic factors = non-living components affecting organisms.

• Populations respond to changes in both biotic and abiotic factors.