Connecting Evolution and Ecology Notes

Connecting Evolution & Ecology

  • Quote by Charles Darwin:

  • "It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change."

Key Concepts

  • Biodiversity: Variation among living things in a particular habitat or ecosystem.

  • Evolution: Process by which all living organisms on Earth have changed over time from early ancestors.

  • Ecology: Study of interactions (relationships) between organisms and their environment (both living and non-living).

Biological Levels of Organization

  • Hierarchy of Organization:

  • Cell: Smallest unit with life functions.

  • Tissues: Groups of cells with similar shapes/functions.

  • Organs: Tissues that work together.

  • Organ Systems: Multiple organs working together.

  • Organisms: Individuals (multicellular organisms like plants, animals, fungi or single-celled organisms like bacteria).

Ecological Levels of Organization

  • Organism: Individual member of a species.

  • Species: Group of organisms that can reproduce naturally and produce fertile offspring.

  • Population: All members of a species in the same area at the same time.

  • Evolution: Genetic (allele frequency) changes that occur at the population level.

  • Biological Community: All interacting populations in an area.

  • Ecosystem: Living (biotic) and non-living (abiotic) factors.

  • Biosphere: All parts of Earth that support life; encompasses all ecosystems.

Habitat and Geographic Range

  • Habitat: Type of environment conducive for species survival. Defined by abiotic (non-living) and biotic (living) factors.

  • Geographic Range: Defines habitat and organism distribution.

Tolerance Ranges and Population Dynamics

  • Tolerance Ranges: Show survivability for a species regarding specific abiotic factors, including optimal, stress, and intolerance zones.

Types of Adaptations

  • Physical Adaptations: Structural differences (coloration, shape).

  • Chemical Adaptations: Poisons, venoms, etc. which deter predators.

  • Behavioral Adaptations: Migration, mating rituals, territory marking.

  • Physiologic Adaptations: Changes in metabolism or cellular processes.

Evolutionary Mechanisms

  • Natural Selection: Process where advantageous traits increase in frequency within a population, enhancing survival.

  • Genetic Variation: Caused by random mutations; can be neutral, harmful, or advantageous.

  • Selection Pressures: Factors affecting an organism's ability to survive (resource availability, environmental conditions, competition).

  • Sexual Selection: Specific traits influencing mating preferences.

Divergence and Speciation

  • Populations can develop genetic differences leading to the reclassification as different species due to isolation.

  • Homologous Structures: Evidence of divergent evolution from a common ancestor.

  • Convergent Evolution: Unrelated species develop similar traits due to similar selection pressures in their environment.

Biodiversity on Earth

  • Dominance of species: Mainly insects, invertebrates, fungi, and bacteria.

  • Estimated Species Diversity: 1.5 million identified; estimated 8.7 million in total.

Artificial Selection

  • The selection process is guided by humans for desired traits in domesticated species (selective breeding).

Taxonomic Nomenclature

  • Linnaeus System: Organizing and classifying organisms based on physical traits (binomial nomenclature).

  • Three-Domain System:

    • Categories: Eubacteria, Archaea, Eukarya (prokaryotic vs. eukaryotic).

Classification of Living Organisms

  • Six-Kingdom Classification:

  • Bacteria: Prokaryotic true bacteria.

  • Archaea: Prokaryotic extremophiles.

  • Protista: Diverse single/multicellular organisms.

  • Fungi: Absorb nutrients externally.

  • Plantae: Multicellular photosynthetic organisms.

  • Animalia: Multicellular consumers.

  • Taxonomic Hierarchy:

    • Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species.

Population Growth Patterns

  • Logistic Growth: S-shaped curve; initial rapid growth slows due to environmental resistance.

  • Exponential Growth: J-shaped curve; rapid growth exceeding carrying capacity, leading to population dieback.

Ecological Niches and Interactions

  • Niche: The role of an organism in its ecosystem.

  • Resource Partitioning: Avoids competition by sharing resources among species.

  • Community Interactions: Includes predator-prey dynamics, competition, and symbiosis.

  • Symbiosis Types:

  1. Mutualism: Both benefit.

  2. Commensalism: One benefits, the other unaffected.

  3. Parasitism: One benefits, the other is harmed.

Conclusion

  • Ecological communities are characterized by complex interactions, growth patterns, and reproductive strategies, exemplified by the diverse relationships found in ecosystems like the African savanna.