Abiotic Effects on an Ecosystem

1. Abiotic Effects on an Ecosystem The weather, soil, and such…

2. Biotic or Abiotic?

3. Biotic or Abiotic? • Abiotic components: non-living components • Chemical, geological, physical factors • Temperature • Light • Water • Oxygen Supply • Soil • Biotic components: living components • Organisms and their relationships with other organisms

4. Role of the Abiotic Environment in Population Growth • Size and growth of population are affected by both biotic and abiotic factors • Organisms are dependent on the abiotic factors of the environment • They also modify these factors! • Plants create shade, preserve water in the soil, consume carbon dioxide, and produce oxygen

5. Sunlight • Source of energy for almost all organisms • Green plants need sunlight for photosynthesis • Adaptations occur to capture as much light as possible • Water is divided into two zones • Photic zone: top layer where sunlight reaches • Aphotic zone: lower layer that sunlight does not penetrate

6. Oxygen Supply • Air is composed of about 20% oxygen • Easy for terrestrial organisms to obtain • Oxygen is returned to the air through photosynthesis • Water contains dissolved oxygen in parts per million • Aquatic organisms extract this oxygen • Pollution can lower oxygen content • Benefits some, harms some

7. Substratum • Soil or rock • Acidity (pH) • Acid rain can make soil pH too low for many plants • Some plants like low pH (rhododenrons and pines) • Texture of soil or clay content • Determine the quantity of water the soil can hold • Minerals • Nitrates, phosphates, and other minerals • Humus quantity • Determined by the amount of decaying plant and animal life in soil

8. Chemical Cycles • Within ecosystems, abiotic elements like nutrients are recycled and reused • Nature has its own effective cycles of abiotic elements, and these cycles are crucial to every living organism on earth • Carbon Cycle • Nitrogen Cycle • Water Cycle • Phosphorus Cycle

9. Carbon Cycle

10. Carbon Cycle • Gaseous carbon dioxide enters the living world via plants • Photosynthesis uses carbon dioxide to produce glucose • Plants use glucose ot make starch, proteins, and fats • Animals eat plants and use digested nutrients to form carbs, fats and proteins • Organic compounds are used in cellular respiration in plants and animals and release carbon dioxide back into the air • The other organic carbons remains in an organism until death – then the decaying process returns it to the air

11. Nitrogen Cycle

12. Nitrogen Cycle • Free nitrogen cannot be used by most organism • Free nitrogen is changed into usable, soluble nitrates by bacteria and lightning strikes • Plants absorb the nitrates and synthesize nucleic acids and proteins • Animals eat the plants and synthesize animal proteins • Plants and animals give off wastes and eventually die • Nitrogen in wastes and dead tissue is released through decay as ammonia • Ammonia is converted into nitrites by chemosynthetic bacteria • Nitrites are converted into nitrates by nitrifying bacteria • Remaining ammonia is broken down to release free nitrogen

13. Water Cycle

14. Water Cycle • The sun heats up water in streams, lakes, oceans, etc • The water turns to vapor and moves into the air (evaporation) • Water vapor in the air cools and condenses into clouds • Eventually, the air cannot hold any more moisture and water falls back to the Earth as precipitation • Water is collected in streams, lakes, oceans or as groundwater

15. Phosphorus Cycle

16. Phosphorous Cycle • Phosphorus is present in compounds that dissolve in water • Plants take in the phosphates from the water • Animals eat the plants and excrete waste that contains phosphates, which are returned to soil or the ocean • When plants and animals die, decay returns more phosphates to the soil or ocean