Study Notes: Ecosystems, Cells, Evolution, and Taxonomy

Ecosystems: Basics and Functions

  • Biotic vs. Abiotic
    • Biotic: Living things (plants, animals, etc.)
    • Abiotic: Non-living things (rocks, water, etc.)
  • Ecosystem _ (term not specified in transcript; likely relates to structure/organization)
    • Note: The blank term is missing from the transcript.
  • Functions: Flow of materials and energy in, through, and out of an ecosystem
  • Integrity: The interactions within an ecosystem that move energy and materials (e.g., animals eating, plants taking up water, etc.)
  • Services: Resources and processes provided by ecosystems to people

Dynamic Homeostasis

  • Main Takeaway: Ecosystems and their processes (functions and integrity) will typically balance themselves out when not heavily disturbed.

Ecosystem Services (Page 10)

  • Cultural
    • Ethical values
    • Existence values
  • Regulating
    • Air quality, climate, water runoff, erosion, natural hazards, pollination
  • Supporting
    • Nutrient cycling, water cycling, soil formation, photosynthesis (note: transcript misspelled as photosynethsis)
  • Provisioning
    • Recreation and ecotourism
    • Food, fiber, biomass
    • Fuel, freshwater, and natural medicines

Which of these is NOT an ecosystem? (Page 11)

  • List (items include various birds, fishes, and lakes):
    • red-tailed hawk, terns, peregrine falcon, The Great Lakes, bald eagle, osprey, tree swallow, pied-billed grebe, walleye, bass, lake trout, bullhead, Double-crested Cormorant, bittern, ruddy turnstone, carp, mallards, perch, etc.
  • Answer (from context): Lakes
    • Why: The rest are organisms or entities that are part of individual species; “Lakes” refers to a geographic feature (though lakes can themselves be ecosystems, the question prompts that item as not an ecosystem in this list).

Feedback Systems

  • Positive Feedback (Page 13)
    • Diagram: Births → Population (N) → Positive Feedback
    • Concept: Growth accelerates as population increases
  • Negative Feedback (Page 14)
    • Example chain: Higher Temps from Sunlight → Cloud Cover → Negative Feedback (temperature regulation via clouds)
    • Concept: Processes that dampen or stabilize system changes

Environment and Economy

  • Valuation approaches to ecosystems:
    • Economic valuation = people’s willingness to pay the costs of conserving ecosystems
    • Ecological valuation = cost of the loss of an ecosystem or service
  • Valuation methods (Economic valuation):
    • Marginal value; Travel cost, Hedonic, Contingent valuations
  • Valuation methods (Ecological valuation):
    • Natural capital, GDP vs GPI, book example of coffee farms near intact rain forests
  • Key idea: Different frameworks exist for valuing ecosystem goods and services, influencing policy decisions

How Much Is The Environment and its Services Worth?

  • Rough estimate:
    • 125 exttrillion125\ ext{trillion} per year (Costanza et al. 2014)
  • Perspective:
    • USA worth 225 exttrillion225\ ext{trillion} (not annual)

Cells: Prokaryotes and Organelles (Pages 17–18)

  • Question: Which organelles are present in bacteria (prokaryotes)? A. Mitochondria B. Chloroplasts C. Nucleus D. Endoplasmic reticulum E. Golgi apparatus F. Lysosomes G. Vacuoles H. None of these
  • Answer: H. None of these
    • Reason: Prokaryotes lack membrane-bound organelles (mitochondria, chloroplasts, nucleus, ER, Golgi, lysosomes, vacuoles)

Cells: Prokaryotic vs Eukaryotic Features (Page 19)

  • Eukaryotic cell
    • Organelles present: Nucleus, Mitochondrion, Endoplasmic reticulum, Golgi complex, Lysosome, Vacuole
    • Other components: Ribosomes (small, but present in both cell types)
  • Prokaryotic cell
    • Genetic material: Nucleoid (not a nucleus)
    • Ribosome: Present (smaller 70S)
    • Likely cell wall: Indicated as WHLD in transcript (interpreted as cell wall)
  • Diagrams indicate key structural differences:
    • Eukaryotes have membrane-bound organelles and nucleus
    • Prokaryotes lack a true nucleus and membrane-bound organelles

Endosymbiont Theory

  • The theory that organelles of eukaryotic cells originated from prokaryotic cells through ingestion of cell material
  • Implication: Explains origin of mitochondria and chloroplasts as ancient symbiotic organisms

Central Dogma of Molecular Biology (Page 21)

  • Concept: Flow of genetic information from DNA to RNA to make functional proteins
  • Central Dogma process:
    • DNA→RNA→Protein\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}
  • Notes:
    • Described in a summary video (referred to as the Central Dogma Process Video)
    • Summary statement: DNA carries genetic information used to synthesize RNA, which is then used to produce proteins

Phylogenetic Trees (Page 22)

  • Concept: Common ancestors and evolutionary relationships
  • Diagram elements:
    • Common Ancestor (time axis)
    • Most recent common ancestor (MRCA) of combinations of species (e.g., A & B; A, B, C, & D; C & D)
  • Labels:
    • Species A, Species B, Species C, Species D
  • Interpretation:
    • The most recent common ancestors indicate branching points in evolutionary history

Taxonomy (Naming of Species) (Page 23)

  • Concept: Taxonomy goes from broad (domain) to specific (species)
  • Scientific notation: Genus species
    • Example given: Pongo abelli
    • Common name: Orangutan
  • Note: The transcript lists Pongo abelli; corrected form is Pongo abelii in standard nomenclature
  • Practical takeaway:
    • Use hierarchical ranking to categorize organisms from broad to specific