Earth Science and Ecology: Ecosystems, Energy Flow, & Biodiversity
Lesson Overview
- What Are Ecological Relationships?
- What Are Biotic and Abiotic Factors?
- How Does Energy Flow in Ecosystems?
- What Is Population Dynamics?
- What Is Ecological Succession?
- What Are Keystone Species?
- How Do Humans Impact Ecosystem Stability?
Earth science encompasses the study of Earth's physical constitution and its atmosphere, while ecology examines relationships among living organisms and their environments. Both sciences are interconnected and essential for understanding the Earth's ecosystems and addressing environmental challenges.
What Are Ecological Relationships?
Here is everything you need to know about ecological relationships:
Symbiosis and Its Scientific Classifications: Symbiosis involves persistent biological interactions between different species, categorized into three primary types:
- Mutualism: Both species gain benefits, exemplified by bees pollinating flowering plants, aiding in reproduction and nutrient acquisition.
- Commensalism: One species benefits without affecting the other, such as barnacles attaching to whales, benefiting from mobility and food availability without harming their host.
- Parasitism: One organism benefits at the expense of another, illustrated by ticks extracting nutrients from mammals, causing potential harm or disease.
Niches and Habitats: An organism's niche encompasses its ecological role, interactions, and resource usage within an ecosystem. Its habitat refers to the specific physical environment where the organism resides. For instance, a frog's niche includes its prey, predators, and its habitat, the pond ecosystem.
What Are Biotic and Abiotic Factors?
Let's understand biotic and abiotic factors in detail:
Biotic Factors: These include all living entities affecting ecosystem functions, encompassing plants, animals, fungi, microorganisms, and decomposers. For example, microbial communities decompose organic matter, contributing essential nutrients to soil fertility.
Abiotic Factors: Abiotic elements significantly influence biological processes, including temperature, sunlight, precipitation, pH levels, salinity, oxygen concentration, elevation, and latitude. Temperature fluctuations, for instance, directly affect species' metabolic rates and distribution.
How Does Energy Flow in Ecosystems?
Let's understand how energy flows in ecosystems:
Food Chains and Food Webs: Energy flows in ecosystems through food chains, which illustrate energy transfer from primary producers to consumers and decomposers:
- Producers (Autotrophs): Organisms like plants and algae utilize photosynthesis to convert solar energy into chemical energy (glucose).
- Consumers (Heterotrophs): Depend on autotrophs or other consumers for energy. They are subdivided into herbivores, carnivores, omnivores, and detritivores.
- Decomposers: Bacteria and fungi break down organic waste and dead organisms, recycling nutrients into the ecosystem, which is crucial for nutrient cycling.
Trophic Levels and Energy Efficiency: Energy transfer between trophic levels follows the 10% rule, meaning about 90% of energy is lost as heat through metabolic processes, resulting in limited trophic levels within ecosystems.
| Trophic Level | Example | Energy Transfer (%) |
| Producer | Grass | 100% |
| Primary Consumer | Grasshopper | 10% |
| Secondary Consumer | Frog | 1% |
| Tertiary Consumer | Hawk | 0.10% |
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What Is Population Dynamics?
Here is everything you need to know about population dynamics:
Limiting Factors: Population size and growth are constrained by factors such as resource availability (food, water, habitat space), predation pressures, competition intensity, climatic conditions, and diseases. Scientific research indicates that limited resources trigger intense competition, influencing survival and reproduction.
Carrying Capacity: Defined as the maximum population an ecosystem sustainably supports, influenced by available resources, habitat quality, and environmental stability. For example, deer populations are limited by the availability of vegetation and predation by wolves.
Population Growth Metrics: Population dynamics calculation:
Population change calculation: (Births + Immigration) – (Deaths + Emigration).
What Is Ecological Succession?
Let's understand ecological succession in detail:
Primary Succession
Occurs on barren landscapes like volcanic rock or newly exposed glacial deposits. Pioneer species, such as lichens and mosses, colonize these environments, gradually creating soil through biochemical weathering and paving the way for complex communities.
Secondary Succession
Initiated after disturbances (wildfires, flooding, human activities) that leave existing soil intact, allowing rapid recovery and colonization by grasses, shrubs, and eventually mature forests.
What Are Keystone Species?
Keystone species, though often few in number, disproportionately influence ecosystem health and stability. The removal of keystone species like sea otters, wolves, or bees drastically disrupts food webs, habitat structure, and biodiversity, leading to significant ecological imbalance.
How Do Humans Impact Ecosystem Stability?
Here is everything you need to know about humans' impact on ecosystem stability:
Invasive Species: Invasive organisms, lacking natural predators in new environments, threaten native biodiversity. For example, zebra mussels disrupt aquatic ecosystems in North America, altering water quality, outcompeting native species, and causing substantial economic impacts.
Conservation Strategies: Effective biodiversity conservation integrates habitat preservation, protecting critical ecosystems such as rainforests, wetlands, and coral reefs; species-specific protection measures, including endangered species recovery programs; and sustainable resource management practices, informed by ecological research and monitoring.
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