Ecology, Classification, and Evolution Notes

Ecology Terms

• Herbivore: Organisms that primarily eat plants.
• Carnivore: Organisms that primarily eat other animals.
• Omnivore: Organisms that eat both plants and animals.
• Decomposer: Organisms that break down dead or decaying organic matter, returning nutrients to the soil.

Symbiotic Relationships

1. Tapeworm (Parasitism):

   • Lives inside an animal host, absorbs nutrients, causes harm.

2. Cattle Egrets (Commensalism):

   • Feed on insects stirred up by cows, benefiting them without harming the cows.

3. Acacia Ants and Bullhorn Acacia (Mutualism):

   • Ants receive food and shelter; acacia gets protection from herbivores.

Food Chain Dynamics

• The ultimate source of energy is the Sun.
• Producers form the foundation of all food webs, having the most available energy.
  • Example: Grass (producer) -> Grasshopper (primary consumer) -> Frog (secondary consumer) -> Snake (tertiary consumer).
• Expected more mice than owls due to energy loss at each trophic level.
  • Increase in foxes leads to a decrease in rabbits, potentially overgrazing on carrots.

Trophic Levels

• Producer: Grass
• Primary Consumer: Grasshopper
• Secondary Consumer: Frog
• Tertiary Consumer: Owl

Energy Availability

• The energy pyramid's most available energy is at the producer level and the least is at the tertiary consumer level.
• Energy loss per level is typically 90%.
• With 12000 kJ for producers, tertiary consumers would have 120 kJ remaining.

Limiting Factors and Carrying Capacity

• Limiting Factors: Elements that restrict population growth, e.g., food, space.
• Connection to carrying capacity: Maximum population an environment can sustain.
  • DD: Competition, Predation, Disease
  • DI: Fire, Drought, Invasive species.

Carbon Cycle

• Carbon leaves the atmosphere via photosynthesis.
• It enters ecosystems through plants as organic compounds.
• Carbon is released back into the atmosphere by respiration and combustion.
• Combustion of fossil fuels increases atmospheric carbon, disrupting the carbon cycle.

Nitrogen Cycle

• Nitrogen Fixation: Process by which nitrogen from the atmosphere (N2) is converted into usable forms for plants by nitrogen-fixing bacteria.
• Eutrophication: Excess nutrients cause algal blooms, depleting oxygen and harming aquatic life.

Biomes

• Terrestrial Biome Determinants: Climate, soil type, and vegetation.

• 6 Major Biomes:

  1. Tropical Rainforest
  2. Desert
  3. Grassland
  4. Savanna
  5. Taiga
  6. Tundra.

• Aquatic Biome Determinants: Salinity, depth, water flow.

Taxonomy and Classification

• Taxonomy: The classification of living organisms.
• Father of Classification: Carl Linnaeus.
• Binomial Nomenclature Rules:
  • Handwritten: Genus capitalized, species lowercase, italicized.
  • Typed: Same rules apply, usually italicized.
• Scientific Name Correction: Candida albicans.

Taxonomy Hierarchy

• Broad to Specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
• Three Domains: Archaea, Bacteria, Eukarya.
• Six Kingdoms:
  1. Animalia
  2. Plantae
  3. Fungi
  4. Protista
  5. Archaebacteria
  6. Eubacteria.

Characteristics of Kingdoms

• Kingdom Identification:
  • a. Animalia
  • b. Protista
  • c. Archaebacteria
  • d. Fungi
  • e. Eubacteria
  • f. Plantae

Evolution and Natural Selection

• Evolution: Change in species over time.
• Natural Selection: Mechanism of evolution, where better-adapted organisms survive and reproduce.
• Biological Fitness: Measure of an organism’s ability to survive and reproduce.

Hardy-Weinberg Principle

• Assumptions: No mutation, selection, gene flow, or genetic drift; large population.

Homologous vs. Analogous Structures

• Homologous Structures: Similar origins but different functions, evidence of common ancestry.
• Analogous Structures: Similar functions but different origins, due to convergent evolution.

Antibiotic Resistance

• Resistance arises from random mutations.
• Bacteria that are not killed reproduce, leading to more resistant strains.

Evolutionary Processes

• Overproduction leads to competition, where variation can provide advantageous traits.
• Descent with Modification: Traits become more common in populations over generations due to selection.