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• Ecological systems:

  • Biological entities with internal processes and interactions with the environment

• Individual:

  • Fundamental unit of ecology

• Boundaries:

  • Locations with gradients of change in environmental conditions

• Producers/autotrophs:

  • Convert CO2 into resources

• Consumers/heterotrophs:

  • Obtain carbon from other organisms

• Mixotroph:

  • Can switch between being producers and consumers

• Detritivores:

  • Break down dead organic matter into smaller particles

• Decomposers:

  • Break down detritus into simpler elements for recycling

• Niche:

  • Range of abiotic and biotic conditions an organism can tolerate

• Parthenogenetic species:

  • Reproduce without fertilization

• Proximate hypothesis:

  • Address immediate changes in physiology, hormones, etc.

• Ultimate hypothesis:

  • Address fitness costs and benefits of a response

• Mean:

  • Observation values for a treatment, gives average using all values in a data set

• Tundras:

  • Coldest biome with little available water and low evapotranspiration

• Boreal forests:

  • Cold and wet with large organic matter storage

• Tropical rainforests:

  • Highest species diversity and biomass, warm and rainy

• Temperate grasslands & Deserts:

  • Have hot dry summers and cold winters

• Subtropical (hot) deserts:

  • Hot temperatures and scarce rainfall

• Woodlands/shrublands:

  • Hot, dry summers and mild, wet winters

• Cold deserts:

  • Evaporation & transpiration > precipitation

• Tropical seasonal forests and savannas:

  • Warm temps, wet dry seasons

• Temperate rainforests:

  • Mild temps, abundant precipitation

• Temperate seasonal forests:

  • Moderate temperature and precipitation

• Temperate coniferous areas:

  • Warmer and drier areas

• Streams and rivers:

  • Lotic ecosystems characterized by flowing water

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• Circulation in lakes:

  • Happens in spring, autumn, and summer

  • Epilimnion (upper layer) warms and stays well mixed and enriched in oxygen

  • Hypolimnion (lower layer) is cooler and has less oxygen

• Natural purification systems:

  • Swamps, marshes, bogs

• Salt marshes:

  • Coastal wetlands flooded & drained by salt water

• Mangrove swamps:

  • Tropical & subtropical coasts with salt-tolerant trees

• Allochthonous:

  • Inputs from outside an ecosystem

• Autochthonous:

  • Inputs produced by algae and aquatic plants inside an ecosystem

• Greenhouse effect:

  • Natural process that warms the earth's surface

  • Greenhouse gases trap heat from the sun in the atmosphere

• Nutrients needed for DNA:

  • CHNOPS, K, Mg, Ca

• Water has high viscosity

• Osmoregulators:

  • Mechanisms organisms use to maintain solute balance

• Sharks/rays:

  • Match the osmolarity of the ocean

• Osmosis:

  • Net diffusion of water

• Fish gills:

  • Extract oxygen from water

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• Thermophilic:

  • Heat-loving organisms

• Water potential gradient:

  • Movement of water from areas of higher to lower potential

• Pressure potential:

  • Positive pressure when water is under pressure, negative pressure when pulled by forces like evaporation

• Stomata:

  • Small openings on leaf surfaces for gas exchange

• Electromagnetic radiation:

  • Energy from the sun in particle-like units called photons

• Photosynthetically active region (PAR):

  • Wavelengths of light suitable for photosynthesis

• Chloroplasts:

  • Organelles in photosynthetic organisms

• Thylakoid membrane:

  • Light-absorbing pigment

• Chlorophylls:

  • Absorb red and violet light, reflect green and blue

• Photosynthesis:

  • Process of converting CO2, H2O, and solar energy into glucose and oxygen

• Light reactions:

  • Convert light energy into chemical energy stored in ATP and NADPH

• Calvin Cycle:

  • Second stage of photosynthesis, fixes carbon dioxide and produces carbohydrates

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• Photosynthesis involves enzyme-mediated reactions using ATP and NADPH to convert CO2 into glucose

  • Allows for continuous regeneration of RuBp

• C4 plants avoid photorespiration using bundle sheath cells

  • Found in high temperature environments (e.g. corn, sugarcane)

  • PEP carboxylase in mesophyll cells, Rubisco/calvin cycle in bundle sheath cells

• C3 plants found in cool/wet environments

  • Rubisco is a problem due to photorespiration

• CAM photosynthesis in dry and warm environments

  • Open stomata at night to reduce water loss (e.g. cacti, agave)

  • PEP carboxylase at night, Rubisco/calvin cycle during the day

• Shallow roots can take up water after brief rainfall events

• Long roots can access deeper waters

• Terrestrial animals are less vulnerable to water loss than plants

  • Urine excretion eliminates excess salts

• Nitrogen is essential for proteins and DNA, excess is excreted as metabolic waste

• Heat transfer: conduction, convection, thermal inertia

• Spatial variation: large scale (climate, topography, soil type), small scale (plant structure, animal behavior)

• Phenotypic plasticity allows organisms to achieve homeostasis and maintain fitness

• Plastic responses to competition for resources

• Hermaphrodites can self-fertilize their eggs with their own sperm

• Organisms can adjust their physiology to maintain activity across different environmental temperatures

• Acclimation: animals respond by moving to different microhabitats

• Diapause: physiological shutdown in response to unfavorable conditions

• Torpor: brief period of dormancy in mammals and birds

• Risk-sensitive foraging influenced by predators

• Diet mixing to obtain all necessary nutrients

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• Pleiotropy: one gene affects multiple traits

• Genetic drift causes random fluctuations in allele frequencies over time

• Founder's effect: few individuals start a new population with random gene flow, mutation, and genetic drift

• Population bottleneck: reduction in gene pool due to a drastic decrease in population size

• Natural selection can be directional, stabilizing, or disruptive

• Speciation can occur through allopatric or sympatric mechanisms

• Polyploidy can occur through autopolyploidy or allopolyploidy

• Sexual reproduction has advantages and disadvantages compared to asexual reproduction

• Fecundity: number of offspring produced per reproductive episode

• Parental investment: time and energy given to offspring

• Environmental sex determination is a type of phenotypic plasticity

• Fundamental niche vs realized niche

• Endemic vs cosmopolitan species

• Clustered, evenly spaced, and random dispersion patterns

• Metapopulation theory for successful species reintroduction

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• Carrying capacity (K): maximum population size supported by the environment

• Different survivorship types: Type I, Type II, Type III

• Die-off: substantial decline in population size

• Overshoot: population grows beyond carrying capacity

• Demographic stochasticity: variation due to random differences among individuals

• Environmental stochasticity: variation due to random changes in environmental conditions

• Metapopulation theory can be applied to reintroduce species into a habitat

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Exam 3:

• Mesopredator: relatively small and consumes herbivores

• Prey population growth: dN/dt= rN-cNP

  • N= # of prey

  • P= # of predators

  • c= probability of encounter b/w predator and prey leading up to capture

• Predator population growth: dP/dt= acNP-mP

  • a= efficiency of a predator turning consumed prey into offspring

  • m= per capita mortality rate of predators

• Equilibrium isocline: both populations stable when growth= 0

  • Stable when: N= M/ac & P=r/c

• Joint equilibrium:

  1. Joint equilibrium point: increase in predator pop. so decline in prey

  2. Decrease in prey pop. so decline in predators

  3. Decrease in predator pop. allows increase in prey pop.

  4. Increase in prey causes predator pop. to increase

• Functional responses:

  • Type I: when a predators rate of consumption increases linearly

  • Type II: predators rate of consumption begins to slow down as prey density grows & then plateaus

  • Type III: predator has low consumption when prey densities are low

    • Slow, fast, then slow again

    • Shows learning curve b/c prey could be hiding, prey switching, or predator has no search image

• Prey have evolved to avoid predation using:

  • Spatial avoidance: warns others to run

  • Crypsis: prey matches background

  • Structural defenses: used to avoid capture or being held

  • Batesian mimicry: palatable species resembles unpalatable one

  • Mullerian mimicry: several unpalatable species evolve to have similar pattern of warning coloration

• Resistance: affects ability to prevent infection immune response or behavior

• Vertical transmission: between parent and offspring

• Vector: living organism that transmits diseases b/w individuals

• Reservoirs: can be provided by hosts, multiple hosts to keep parasite alive

• Tolerance: minimize harm from infection

• Susceptible infected resistance model (S-I-R):

  • S= susceptible

  • I= infected

  • R= resistant

  • b= rate of transmission

  • g= rate of recovery

• R> 1= infection will spread

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• R< 1= infection won't spread

• R=1, will remain stable

• Toxoplasma: parasite that alters mammal behavior

• Counterattacks in response to host’s immune defenses:

  • Avoidance

  • schistosomes (protective layer)

  • Evolving (red queen theory)

• Intraspecific competition: among same species

• Interspecific competition: among different species

• Allochthonous: external, resources do not respond to rate of consumption

• Autochthonous: resources affected by supply & demand

• Leibig’s law of minimum:

  • Smallest resource limits pop.

  • Pop. increases until supply of most limiting resource prevents it from increasing

• Competitive exclusion: extreme overlap in resources- one species wins

  • competition “showdown”

• N1 = K1 - αN2:

  • If N2= 0, then N1 = K1

  • N1= 0, then N2 = K1/α

• N1< isocline, population grows

• N1> isocline, population shrinks

• N2> isocline, population grow

• N2> isocline, population shrinks

• Abiotic factors: non-living components of the ecosystem like oxygen, pH, temp., sunlight, etc

• Types of competition:

  • Exploitative competition: ind. remove resource to a point that others can’t persist

    • Indirect competition: via shared resource

  • Interface competition: competitors do not consume but defend resources

    • direct competition

  • Apparent competition: 2 species have a neg. effect on each other through an enemy

    • including predator, parasite or herbivore

• Allelopathy: interference competition using chemical warfare

• Obligate relationship: if need each other to live

• Facultative: if interaction not critical for survival

• Endophyte: chemical defense, drought resistance

• Mutualism can affect species distributions and communities

  • Disruption of mutualism may cause decline of species involved

  • affects communities bc it can cause changes in abundance & diversity of species

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• Community: different species living together in an area

• Terrestrial system: categorized by dominant organisms

• Aquatic system: categorized by physical characteristics & dominant organisms

• Ecotones: where 2 communities integrate

  • Support lots of species

• Frederic Clements: thought species were interdependent & act as superorganisms

  • Interdependent communities: depend on each other to exist

  • If he was right, species should co-occur consistently

• Henry Gleason: thought species do not depend on each other

  • If correct, species presence is unrelated to another species

• To test interdependence remove species & observe

  • If interdependent, remaining species should decline

  • Independent species should thrive

• To calculate relative abundance:

  • Species Abundance Relative abundance

  • Foxes 10 5%

  • Chickens 90 45%

  • Farmers 10 5%

  • Pigs 90 45%

  • Total 200

• Steps:

  • Add up abundance numbers

  • Divide abundance # by total then multiply by 100

    • So, 10/ 200= 0.05

    • 0.05 x 100= 5% (foxes)

• Rank-abundance species: plots the relative abundance of each species in a community in rank order from most to least abundant

  • Starting with the most abundant, will have rank of 1

• Rank abundance curve:

  • X= richness

  • Slope= evenness

  • Steeper slope means less Abundance

• Evenness: “mix” of species

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• Hump-shaped theory:

  • Diversity is highest at intermediate productivities

• Keystone species: species that substantially affects the structure of communities

  • Removal can cause a community to collapse

• Intermediate disturbance hypothesis: diversity is greatest in communities with “occasional” disturbances

• Trophic cascade: indirect effects in a community that are initiated by a predator

• Density mediated: caused by changes in the density of an intermediate species

• Trait-mediated effect: caused by changes in the traits of an intermediate species

• Top-down effect: higher trophic level influences community structure of lower level through predation

• Bottom-up effect: lower trophic level affects community structure of higher levels by restricting resources

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• Chapters 17-20:

• Succession: how the species composition of a community changes over time

  • Directly observed: long term studies

  • Indirect observation: sequence of communities that exist over time at a given location

  • Palynology: study of plant pollen, spores, & certain microscopic plankton organisms in both living & fossil form

• Primary succession: occurs when an area experiences a disturbance so severe that none of the original species survive

• Secondary succession: happens when a climax community or intermediate community is impacted by a disturbance

  • Often follows natural disasters

  • Soil survives which helps vegetation regrow rapidly

• Aquatic succession: gradual infilling of a shallow lake or pond with sediments and organic matter until the vegetation takes over and turns it into a mature upland

• Terrestrial succession: can occur as primary or secondary succession

• Lake succession:

  1. Plants colonize edge of the water -- Detritus accumulates

  2. The plants spread laterally across -- More accumulation

  3. Plants expand

  4. Covers the lake surface, and peat sediments fill the basin

• Fast model:

  1. Periodic droughts lasting a decade

  2. Plants colonize the newly exposed sediments

  3. Drought ends, living plants detach from sediments - deposit detritus

  4. Peat sediments eventually fill the basin

• Facilitation: one species increases the probability that a second species becomes established.

• Inhibition: one species decreases the probability that a second species becomes established.

• Tolerance: probability that species can become established depending on their ability to get the habitat and persist under the physical conditions of the environment.

• Gaps in a climax community

  • Small scale disturbances in a climax community can allow the growth of species that are not considered climax species.

• Climax community is the end point of a succession

• GPP: energy captured and assimilated by producers

• NPP: all captured energy that is not respired, energy that becomes biomass

• Community stability: the ability of a community to maintain a particular structure (diversity, composition, etc).

• Community resistance: the amount a community changes when acted upon by a disturbance (e.g., addition or removal of a species).

• Community resilience: the time it takes after a disturbance for a community to return to its original state.

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• Alternative stable states:

  • Disturbance can cause changes in species composition and relative abundance in a community.

  • New community structure becomes resistant to further change.

  • Example: Removing a keystone species.

• Global productivity:

  • Refers to the rate at which organic matter is produced by organisms in ecosystems.

  • Primary production is the process of organic matter production.

  • Primary production forms the foundation of the food chain and supports all life on Earth.

• Hotspots:

  • Productive terrestrial ecosystems include tropical rainforests, wetlands, and agricultural lands.

  • These areas contribute significantly to global food production.

  • They support diverse communities of plants and animals.

• Net Productivity:

  • Percentage of assimilated energy used for growth and reproduction.

• Assimilation:

  • Percentage of consumed energy that is incorporated into an organism.

• Ecological:

  • Percentage of net production from one trophic level compared to the next lower trophic level.

• Residence time:

  • Length of time that energy is spent in a given trophic level.

  • Longer residence time leads to greater accumulation of power in that trophic level.

• The carbon cycle:

  • Linked to energy through photosynthesis.

  • During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen.

  • Glucose serves as an energy source for plants and organisms that consume them.

  • Respiration breaks down glucose, releasing energy for life processes.

• Carbonate Sedimentation:

  • Formation of carbonate minerals and rocks like limestone and dolomite.

• Weathering of Rocks:

  • Breakdown of rocks on the Earth's surface.

• Carbon Fixation:

  • Conversion of inorganic carbon (CO2) into organic compounds by living organisms.

• Mineralization:

  • Breakdown of organic carbon compounds back into inorganic forms, primarily CO2.

• Denitrification:

  • Process related to the nitrogen cycle, not the carbon cycle.

  • Conversion of nitrates (NO3-) into nitrogen gas (N2) by specific bacteria.

  • Enriches soil fertility, supports plant growth, maintains nitrogen cycle balance, and reduces reliance on artificial fertilizers.

• Ecological Stoichiometry:

  • Balance of nutrients in