Answer:
Step-by-step explanation:
Biogeography and Biodiversity:
Biogeography is the study of the distribution of living organisms on Earth and the factors that influence their geographical patterns. It examines how ecological and evolutionary processes shape the diversity and distribution of species across different regions and ecosystems.
Biodiversity refers to the variety of life on Earth, including the number of different species, their genetic variability, and the diversity of ecosystems in which they exist. Biodiversity is essential for maintaining ecological balance, providing ecosystem services, and supporting human well-being.
Powers of the Biosphere and Chemical Processes:
The biosphere is powered primarily by solar energy. Solar radiation drives photosynthesis, a chemical process in which plants and some microorganisms convert carbon dioxide and water into glucose (energy-rich organic compound) and oxygen, using sunlight as the energy source.
In respiration, organisms, including plants, animals, and microorganisms, consume oxygen and release carbon dioxide while breaking down glucose to produce energy for their cellular activities.
Net Primary Productivity (NPP) and Geographic Variation:
Net Primary Productivity (NPP) represents the energy captured by plants through photosynthesis minus the energy used during respiration. It indicates the amount of energy available for consumption by other organisms in the ecosystem.
NPP varies geographically due to factors like temperature, precipitation, and nutrient availability. Generally, NPP is higher in regions with abundant sunlight, warmth, and adequate water and nutrients.
Factors Affecting NPP:
Several factors influence NPP, including climate, soil fertility, water availability, and species composition. Higher NPP is observed in ecosystems with high biodiversity, as different species can efficiently utilize available resources.
Highest and Lowest NPP Ecosystems:
Tropical rainforests and estuaries have some of the highest NPP levels due to their favorable environmental conditions and species diversity. Deserts and open oceans, on the other hand, have lower NPP due to limited resources and harsh conditions.
Energy Availability and the Food Chain:
As energy moves up the food chain, it becomes less available to higher trophic levels due to energy loss at each transfer. The 10% rule states that only about 10% of the energy is passed on from one trophic level to the next. The remaining 90% is lost as heat or used for metabolism by organisms at each level.
Impact on Population Sizes:
The reduced energy availability limits the number of organisms that can be supported at higher trophic levels. As a result, population sizes of higher-level consumers (e.g., carnivores) are smaller than those of primary producers (e.g., plants).
Solar-Energy Efficient Diet for Humans:
A plant-based diet has the highest solar-energy efficiency for humans because it requires less energy input, compared to animal-based diets, which involve energy losses at multiple trophic levels.
Biomagnification:
Biomagnification is the process by which certain toxic substances become increasingly concentrated in the tissues of organisms as they move up the food chain. It is most problematic for higher trophic levels, such as top predators.
Species Distributions and Endemism:
Species distributions can be cosmopolitan (found worldwide), endemic (restricted to a specific region), or disjunct (occurring in separate, isolated locations). Endemism is increased by geographical isolation and unique ecological conditions that limit species' ranges.
Tropical Diversity Gradient and Biodiversity:
The latitudinal diversity gradient refers to the pattern of increasing species diversity from the poles towards the equator. The tropics act as a cradle and a museum for biodiversity, as they support high rates of speciation and maintain a high diversity of ancient species.
Roles of Evolution and Extinction:
Evolution contributes to biodiversity by generating new species through speciation. The tropics have historically experienced higher rates of speciation. Extinction also plays a role, but the tropics have generally experienced lower extinction rates compared to other regions, contributing to their biodiversity hotspot status.