Ecosystems and Biodiversity Overview

Ecosystems are crucial for human survival and well-being.
The focus is on energy transfers that maintain biodiversity and the management of ecosystems for conservation.

Soil Composition: Minerals, nutrients, air, and water.
Functions:
- Supports plant growth by providing a medium for anchorage.
- Supplies essential nutrients for plant growth.
Factors influencing soil development:
- Climate (e.g., rainfall affects plant types and leaching).

Impact of Climate: Determines the distribution of species globally, with organisms adapting to local temperature and precipitation.
Biomes: Large ecological areas defined by soil, climate, vegetation, and wildlife characteristics. Main types include:
- Deserts: Located between 15° and 35° latitude.
- Forests
- Grasslands
- Tundra

Temperature:
- Day: Approximately $38^{ ext{°C}}$ (over $100^{ ext{°F}}$ ).
- Night: Approximately $-3.9^{ ext{°C}}$ (about $25^{ ext{°F}}$ ).
Precipitation: About $250 ext{ mm}$ per year, the lowest among biomes.
Plant Adaptations:
- Cacti store water in stems; leaves may be reduced to minimize water loss.
- Bushes have large roots to maximize water uptake.

Examples of Adaptations:
- Waxy leaf coatings to minimize evaporation.
- Long roots to access deep water sources.
- Reduced leaf surface to limit transpiration.
- Spines for protection from herbivores.

Diurnal Temperature Range: Fluctuation between daytime and nighttime temperatures.
Convectional Rainfall: Caused by solar heating leading to evaporation, condensation, and cloud formation.

Desert Soil Composition:
- Contains soluble salts and is primarily sandy (90% sand, 5% clay).
- Porous and coarse, allowing for rapid drainage due to high evaporation rates.

Temperature Ranges:
- Winter: From $-40^{ ext{°C}}$ to $20^{ ext{°C}}$ .
- Summer: Approximately $10^{ ext{°C}}$ ( $50^{ ext{°F}}$ ).
Precipitation Levels: Ranges from $300$ to $900 ext{ mm}$ annually.
Vegetation:
- Coniferous trees with cones and needles, adapted to snowy conditions.
- Thick bark for protection against fires.

Environment: Cold, frozen landscape with harsh conditions.
Rainfall: Less than $25 ext{ cm}$ (10 inches) annually.
Soil Composition: Predominantly permafrost, allowing only a thin thawed layer for roots.
Vegetation: Low-lying grasses and bushes; trees are rare due to extreme conditions.

Definition: Orderly changes in an environment leading to a stable climax community.
Types:
- Primary Succession: Begins in lifeless areas (e.g., after volcanic eruptions).
- Pioneer Species: First organisms to colonize bare rock (e.g., lichens).
- Secondary Succession: Occurs in areas that were previously occupied but disturbed (e.g., after forest fires).
Stages in Succession:
1. Colonization: Occupation by pioneer species.
2. Establishment: Increase in species diversity.
3. Competition: New species colonize, altering microclimates.
4. Stabilization: Establishment of late colonizers, leading to complex food webs.
5. Climax Community: A stable community with minimal new species influx.

Definition: Rate at which energy is converted into organic material by photosynthesis.
Gross Primary Productivity (GPP): Total productivity of an ecosystem.
Net Primary Productivity (NPP): GPP minus energy lost through respiration, calculated as:
$ext{NPP} = ext{GPP} - R$
Factors Affecting NPP:
- Energy captured by producers, usually higher in tropical regions.
- Nutrient availability and climate conditions.

Types:
- Pyramid of Energy: Shows energy flow and decreases at higher trophic levels.
- Pyramid of Numbers: Counts individual organisms, does not account for size.
- Pyramid of Biomass: Mass of organisms measured at different trophic levels, variable in aquatic vs terrestrial ecosystems.
Importance: Provides insight into ecosystem health and energy transfer efficiency.
Limitations: Does not account for seasonal variations, species occupying multiple trophic levels, or the size of organisms.