EXAM 3 BIO

Solar Radiation and Latitudinal Variation

Uneven distribution of solar irradiance due to Earth's spherical shape→ different temps, seasonality, precipitation

Hadley Cells

🌧 Rising air = rainy(0,60); ☀ sinking air = dry(30,90)

Rain Shadow Effect

rain on windward side of mountain and dry on the other side

Mean Annual Temperature

Average temperature of a region over a year, used to predict the type of terrestrial biome(latitude, ocean currents)

Mean Annual Precipitation

hadley cell decides this

0

equator

sun hits most directly

VERY low seasonality(day length, temp)

high precipitation

23.5° N to 23.5° S

• warm temperatures year-round

• low temperature seasonality

• precipitation varies

30N/S

• Subtropics

• sun hits relatively directly

• moderate seasonality (varies by location)

• LOW precipitation (dry air sinks)

• many deserts

60° N/S — Subpolar regions

• sun hits at a lower angle

• HIGH seasonality (especially temperature)

• often high precipitation (rising air)

90° N/S — Poles (Polar regions)

• sun hits at the lowest angle

• VERY high seasonality (day length, temperature)

• low precipitation (cold, dry air)

MacArthur-Wilson Theory of Island Biogeography

species richness on island based on immigration+extinction rates

large, close to mainland

high immigration, low extinction

island immigration low if..

species number increase, island far from mainland

extinction increase if…

species number high

extinction low if…

island size is large

Immigration Rate (I)

Rate at which new species arrive on an island, influenced by the island's distance from the mainland.

Extinction Rate (E)

Rate at which species are lost from an island, primarily determined by the island's area.

Exponential Growth

Population growth model where the growth rate is constant, leading to a J-shaped curve regardless of population density

Logistic Growth

Population growth model that incorporates carrying capacity (K) and results in an S-shaped curve as resources become limiting

Trophic Levels

Various levels in an ecosystem's food chain, starting from primary producers to secondary and tertiary consumers.

10% Rule

Ecological principle stating that approximately 10% of energy at one trophic level is converted into biomass at the next higher trophic level.

Carbon Cycle

Biogeochemical cycle involving the movement of carbon among reservoirs such as the atmosphere, living organisms, and sediments.

Cultural Eutrophication

Human-caused nutrient over-enrichment of water bodies leading to algal blooms and degradation of aquatic ecosystems.

Intrinsic Rate of Increase (r_max)

The maximum potential growth rate of a population under optimal environmental conditions.

Fitness Trade-Offs

The compromise between traits that enhance reproductive success and traits that enhance survival, leading to various strategies in offspring production.

Niche Differentiation

Evolutionary process where similar species adapt to use resources differently to minimize competition.

Symmetric Competition

competing species both reduce fitness to the same effect

Asymmetric Competition

Competition where one species suffers a greater fitness reduction than the other due to resource use.

Fundamental Niche

The theoretical range of environmental conditions that a species can occupy without competitors.

Realized Niche

The actual conditions and resources that a species occupies in nature, limited by competition and other interactions.

Per Capita Rate of Increase ($r$)

The per capita growth rate of a population calculated as per capita births minus per capita deaths ($r = b - d$); determines whether a population grows ($r > 0$), stays stable ($r = 0$), or declines ($r < 0$).

Intrinsic Rate of Increase ($r_{\max}$)

how fast a population can grow under ideal conditions, exponential growth

Principle of Allocation

The evolutionary trade-off concept stating that organisms have a finite energetic and metabolic budget, requiring allocations between reproduction, parental investment, growth, and survival.

Exponential Growth

Density-independent population growth modeled by $\frac{dN}{dt} = r_{\max} N$, producing a $J$-shaped curve when per capita growth rate remains constant and resources are non-limiting.

Carrying Capacity ($K$)

max population size and environment can support(how many), logistic growth

Logistic Growth

Density-dependent population growth modeled by $\frac{dN}{dt} = r_{\max} N \left(\frac{K - N}{K}\right)$, which forms an $S$-shaped (sigmoid) curve as growth rate decelerates to zero near carrying capacity.

Density-Dependent Factors(CDPPT)

competition

disease

parasitism

predation

territoriality

Density-Independent Factors

Abiotic forces that alter population mortality or fecundity such as severe weather, wildfires, and floods.

Fundamental Niche

theoretical suite of abiotic and biotic conditions that an organism can physiologically tolerate and survive in without competition or predation

living in lj for free

Realized Niche

The actual, restricted ecological space and range of resources an organism occupies in nature due to constraining biotic interactions

living in ranch

Competitive Exclusion Principle

The ecological proposition stating that two species with identical ecological niches cannot coexist indefinitely if resources are limiting; the superior competitor drives the other to local extinction.

Resource Partitioning

competing species divide resources so they can coexist

ex: different bird species eat insects at top, middle, and bottom of tree

Character Displacement

competing species become more different :competition→natural selection→ evolution→

Mutualism

($+/+$) both species benefit

bees get nectar from flower, flower gets pollenated

Commensalism

($+/0$) barnacles on whales for transportation

Amensalism

($-/0$)tree shades small plants below it so they can’t grow

intrasepcific competition(-/-)

love triangle- 2 of same species competing for same thing(2 deer for mate)

interspecific competition

turf war- different species compete for same resources

consumption

good for one bad for other

mutualism

good for both

Gross Primary Productivity (GPP)

The total amount of radiant solar energy converted into chemical bond energy per unit area per unit time by autotrophic producers.

Net Primary Productivity (NPP)

what is stored as biomass stored after using energy from photosynthesis for cellular processes in producers

NPP formula

($\text{NPP} = \text{GPP} - R$ ), representing the actual biomass available to heterotrophs.

ex: 1000(gpp)-400(respiration)=600 units of energy(npp)

GPP

total energy a plant captures+ concerts thru photosynthesis

R

cellular respiration- plant uses some GPP to fuel life processes

10% Rule (Pyramid of Productivity)

only abt 10% of energy from one tropic level is transferred to next

ex: grass(producer) has 10,000→grasshopper(1 cons) 1,000→frog(2 cons)100

what is other 90% used for?

life processes, released as heat, or undigested

Cultural Eutrophication

Nutrient pollution caused by synthetic fertilizer runoff (nitrogen and phosphorus) that triggers excessive algal blooms, leading to microbial decomposition, dissolved oxygen depletion, and hypoxia.

atlantic ocean

brings warm water from equator to east coast

pacific currents

bring cold water from arctic

northern hemisphere ocean currents

clockwise →

southern hemisphere ocean currents

counterclockwise←