Ecology & Biogeography - Lecture Flashcards (Video Notes)

A set of practice questions (Question and Answer format) covering key concepts from the ecology/biogeography lecture notes.

How is the Environment defined in these notes?

All factors and phenomena outside the organism that influence it; includes abiotic (physical/chemical) and biotic (other organisms) factors.

Why study ecology, according to the notes?

Because organisms modify their environment, ecological theories help us understand human and other organismal impacts, and it guides ecosystem management, preservation, and restoration.

What are the types of ecological studies listed?

Surveys; whole-ecosystem manipulations; large mesocosm studies; small microcosm studies; mathematical modeling; large datasets – citizen science.

What is Whittaker’s Diagram used for?

Biomes are predicted largely by temperature and precipitation (climate), with site history also influencing biomass/soils.

Why focus on plants in terrestrial biome ecology?

Plants are the primary producers; they provide energy and biomass; functional traits tend to be similar within a biome.

What is the basic photosynthesis equation?

6CO2 + 6H2O + Light energy → C6H12O6 + 6O2.

What are the main limitations to terrestrial photosynthesis noted?

CO2 is generally not limiting in terrestrial ecosystems; water (liquid) and light can be limiting; CO2 in plant tissues can also limit photosynthesis.

What are the three photosynthetic pathways and their general advantages?

C3: common and efficient in cool, moist environments but can be limited by CO2; C4: more water-use efficient, better under high temp/drought; CAM: very water-efficient, CO2 fixed at night for arid environments.

What pigments are involved in photosynthesis as noted?

Chlorophyll a and b; bacteriochlorophylls; phycobilins (phycobiliproteins).

Describe Tropical Rain Forest climate and structure.

Warm temperatures, high precipitation; tall trees; intense light competition; nutrient-poor soils with rapid nutrient turnover.

Describe Desert climate and ecosystem structure.

Dry climate; very low photosynthesis/production; sparse drought-tolerant plants; soils with low organic matter; high sensitivity to desertification.

What are the main characteristics of Temperate Forests and Boreal Forests?

Temperate Forests: seasonal variation, relatively high precipitation, broadleaf deciduous trees; nutrient-rich soils. Boreal Forests: long cold winters, short summers, evergreen conifers, thin soils, relatively simple food webs.

What are Temperate Grasslands like?

Seasonal temperature/precipitation variation; regular fire and grazing; deep root systems; highly fertile soils.

What is the role of Earth’s rotation and Coriolis effect in climate patterns?

Rotation and Coriolis forces drive atmospheric circulation cells, affecting wind patterns and precipitation, contributing to large-scale climate structure beyond latitude alone.

What influences soil profiles across biomes?

Soil history and composition (organic matter, nutrients) influence water availability and nutrient retention, affecting plant growth and ecosystem function.

What characterizes open ocean productivity?

Surface waters are generally nutrient-poor; productivity is often linked to upwelling near continental edges and nutrient-rich surface waters in those zones.

What are CPOM and FPOM in Rivers and Streams, and what do they form the base of?

Coarse Particulate Organic Matter (CPOM) forms the base of the food web in headwater streams; Fine Particulate Organic Matter (FPOM) forms the base in larger rivers.

What is the difference between Benthic and Pelagic zones?

Benthic zones are habitats on the bottom substrate; Pelagic zones are habitats in the water column.

What is a Riparian Zone and a Littoral Zone?

Riparian Zone: transition between aquatic and terrestrial environments, typically dry with trees; Littoral Zone: transition between aquatic and terrestrial, often wet with algae and emergent plants.

What is the basic concept of osmoregulation in marine vs freshwater environments?

Marine bony fish drink seawater to compensate for water loss and actively excrete salts; freshwater fish absorb ions from water and excrete dilute urine; both balance ions and water according to environment.

What are the three main energy sources for organisms?

Organic molecules (heterotrophs), Light (photosynthetic autotrophs), Inorganic molecules (chemosynthetic autotrophs).

What is a autotroph and its subtypes?

Autotroph uses inorganic carbon; Photoautotroph uses light as energy; Chemoautotroph uses inorganic or organic energy sources to fix carbon.

What are the three major photosynthetic pathways and where are they advantageous?

C3: common in moist, cool environments; C4: advantageous under high temperature/limited water; CAM: highly water-efficient, common in arid environments.

What defines photosynthetic pigment importance in light capture?

Light-absorbing pigments (chlorophylls, bacteriochlorophylls, phycobilins) determine how plants capture photons (PAR) for photosynthesis.

What is the difference between endotherms and ectotherms?

Endotherms generate heat metabolically to maintain body temperature; ectotherms rely on external heat sources to regulate body temperature.

What is the difference between homeotherms and poikilotherms?

Homeotherms maintain a relatively constant body temperature; poikilotherms have body temperatures that vary with the environment.

What is the Thermal Neutral Zone (TNZ)?

The range of external temperatures over which an endotherm’s metabolic rate remains relatively stable (not changing with temperature).

What are heat transfer mechanisms, and what do they each involve?

Conduction (direct contact heat transfer), Convection (heat via fluid movement), Radiation (heat via electromagnetic waves), Evaporation (heat loss with water vapor).

What are key plant strategies to avoid overheating in deserts?

Decrease conduction, increase convective cooling, reduce radiative heating (reflective surfaces, leaves oriented to sun), and limit evaporative cooling as a secondary option.

What are key plant strategies to stay warm in Arctic/alpine environments?

Increase conduction, reduce convective cooling, increase radiative heating (dark pigments), and maintain a low growth form.

What is the Principle of Allocation in temperature adaptation?

Tradeoffs exist; adaptations to local environments impose constraints that limit optimal fitness across all conditions.

What is acclimation vs adaptation?

Acclimation is a physiological change within an individual due to environment; adaptation is an evolutionary change in a population via natural selection.

What is phenotypic plasticity?

The ability of a single genotype to produce different phenotypes in response to environmental conditions.

What is heritability in the context of phenotypic variation?

The proportion of total phenotypic variation in a trait attributable to genetic variance.

What are the three basic mechanisms of evolution?

Natural selection, Migration, Mutation; plus Genetic Drift.

What are Hardy-Weinberg assumptions?

Random mating; no mutations; large population size; no migration; all genotypes have equal fitness.

What is local adaptation?

Natural selection produces populations specialized for their own environments; natives have higher fitness in their environment than migrants.

What is the general idea behind the optimal foraging model?

Foraging behavior is favored by natural selection when it enhances fitness by maximizing net energy intake per unit time.

What are the three components of optimal foraging in diet selection?

Searching (finding prey), Handling (capturing/killing/eating), Energy (energy gained per unit of prey).

What are Type 1, Type 2, and Type 3 functional responses?

Type 1: linear increase in intake with prey density; Type 2: intake increases but plateaus due to handling time; Type 3: sigmoidal (low intake at low density, then increases, then plateaus) due to searching efficiency and handling.

What is the difference between @Open Ocean productivity and nutrient dynamics?

Open ocean is often nutrient-poor near the surface; productivity is driven by nutrient delivery (upwelling, surface processes) and light availability in the photic zone.

What is the photic zone?

The upper layer of aquatic environments where light penetrates enough for photosynthesis; about 80% of light is absorbed in the first 10 m of water.