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:
Mutualism: Both benefit.
Commensalism: One benefits, the other unaffected.
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.