Key Principles of Ecology and Evolution

Key Principles of Ecology

• Populations evolve genetically over time in response to environmental pressures.
• Interacting species influence each other's evolution (e.g., predator-prey).
• All species share a single evolutionary history.
• Populations naturally fluctuate in abundance due to environmental and biological factors.
• Population growth is limited by resources and environmental constraints.
• Populations can be sustainably harvested with proper management.
• Communities are diverse, shaped by interacting species, biodiversity, and climate/geography.
• All populations eventually go extinct, shaping biodiversity.
• Communities change in response to environmental changes.
• Nutrient cycles are essential for ecosystems and sustainability.
• Ecosystems provide air, water, and food.
• Overuse of shared resources leads to depletion.
• Humans are cooperative by nature.

Darwin's Contributions to Evolutionary Theory

• Darwin provided the mechanism of natural selection.
• Darwin popularized the term "survival of the fittest." (though he didn't coin it).
• Organisms vary in traits, some of which are heritable.

Co-evolution of Species

• Species evolve in response to each other, leading to reciprocal adaptations.
• Examples include predator-prey relationships, human impacts on biodiversity, and intentional (agriculture) and unintentional (antibiotic resistance) co-evolution.

One True Tree of Life

• Species are connected through evolutionary lineages.
• Humans and chimps share a common ancestor.
• Evolution is not linear; it's highly branching.

Populations Fluctuate in Abundance

• Extinction is inevitable for all populations.
• Small, isolated populations are more vulnerable to extinction.
• Minimum Viable Population (MVP) is the smallest size for a population to survive long term.
• Meta-populations are linked by migration, with source populations producing excess individuals and sink populations needing immigrants to persist.
• Conservation focuses on preserving source and meta-population structures.

Additional Topics

• Reciprocity with the land leads to deep connections and sustainability.
• Humans have an innate tendency to connect with nature.

Energy and Diversity in Ecosystems

• Energy limits the complexity of ecosystems.
• Higher net primary productivity (NPP) supports more individuals and species.
• Diversity types exist within ecosystems (alpha, beta, gamma).

Climate and Diversity

• Climate harshness limits the number of species in a region.
• Stable tropical climates support higher species diversity than variable temperate regions.
• Historical events and evolutionary rates influence species diversity in different areas.
• Species-area relationships state larger areas support more species.

Community Ecology and Sustainability

• Key interactions among species include predation and competition.
• Mutualism describes beneficial relationships between species.
• Harvesting affects entire communities.
• Sustainable harvesting considers community impacts.
• Species distribution factors include habitat availability, evolutionary history and barriers to movement.
• Invasive species impact native species.

Sustainable Practices

• Harvest sustainably (less than maximum sustainable yield).
• Evaluate community-wide impacts of human activity

Patterns of Biodiversity

• Biodiversity is not evenly distributed across the planet.
• Energy limits the number of species an ecosystem can support.
• Extinction rates increase as the species richness in an environment increases.

Sustainable Harvesting

• Take "interest" (growth) while preserving "capital" (population size).
• Example practices that follow this principle include early human practices like hunting mammoths or gathering medicinal plants.
• Population growth can follow exponential or logistic growth models.

Indigenous Knowledge & Active Management

• Indigenous practices use controlled burns to promote biodiversity.
• Controlled burns provide materials like birch.
• Other active management approaches including fire prevention are needed for top predators, grazing, and maintenance.

Energy Flows and Dissipates

• Usable energy decreases, entropy increases in a closed system.
• Energy dissipates as heat in an open system (Earth).
• Ecological implications: higher extinction risks and reduced ecological footprints for higher trophic levels.

Nutrient Cycles

• Energy flows, nutrients cycle (e.g., carbon, nitrogen, phosphorus).

Ecosystem Services

• Examples include pollination, climate regulation, and water supply from various ecosystems.
• Ecosystem services are economically valuable.

Tragedy of the Commons

• Public resources are overused when individual benefits outweigh shared costs.

Cooperation and Mutualism

• Cooperation is as significant as competition.
• Strategies for encouraging cooperation include kin selection, reciprocity, repeated interactions, incentives, and even punishment.

Tree of Life

• Species branching from common ancestors.

Carrying Capacity

• Maximum population environment can sustain based upon the resources available.

Biophilia

• Innate tendency to seek connections to nature and other forms of life.

Maximum Sustainable Yield (MSY)

• Largest amount of a resource that can be sustainably harvested without depleting it.

Species-Area Relationship

• Larger areas generally support more species due to greater habitat diversity.

Ecological Niche

• Role and position of a species in its environment, including resources used and interactions with other organisms.

Extinction Risk

• Likelihood of a species becoming extinct, influenced by factors such as population size and habitat conditions.