Ecology: Principles, Hierarchies, and Adaptations in Biological Systems

Who defined ecology as 'the body of knowledge concerning the economy of nature'?

Ernst Haeckel

What does the term 'economy of nature' refer to?

The body of interactions that either increase or decrease ecological variables.

What are the two main types of elements studied in ecology?

Biotic elements (living organisms) and abiotic elements (non-living components).

What is meant by 'ecological hierarchy'?

The organization of ecological study from organisms to populations, communities, and ecosystems.

What is the significance of water in ecosystems?

Water supports organisms, affects osmotic balance, and is a key limiting nutrient in aquatic systems.

What is the euphotic zone?

The narrow zone close to the surface of water where there is sufficient light for photosynthesis.

What are the four principal factors affecting temperature in organisms?

Radiation, conduction, transpiration, and convection.

What is the Q10 relationship in ecology?

It describes how metabolism changes with temperature in ectothermic organisms.

What does 'synergism' mean in ecological interactions?

An interaction between two or more variables that leads to a greater effect than the sum of individual effects.

What is the role of day length in plant flowering?

Day length influences flowering timing; short day plants bloom early, while long day plants bloom later.

How does the thermal environment affect reproductive success?

The thermal environment can determine fecundity, or reproductive success, in species.

What is the greenhouse effect?

A physical phenomenon where energy from the sun is absorbed and retained by greenhouse gases, warming the Earth's surface.

What are the two main limiting nutrients in aquatic systems?

Nitrogen in marine systems and phosphorus in freshwater systems.

What is the relationship between photosynthesis and water cost in plants?

Photosynthesis has a high water cost; for every gram of CO2 converted into sugars, plants lose 540 grams of water.

What does 'edaphic' refer to in ecology?

It pertains to soil and its properties.

What is the significance of the leaf-area index (LAI)?

LAI influences light availability and temperature in ecosystems.

What is the primary function of ozone in relation to UV radiation?

Ozone shields the Earth from harmful UV radiation.

What are the major principles governing ecosystems?

1) Ecosystems are physical entities; 2) They exist in dynamic steady states; 3) They require energy expenditure; 4) They undergo evolutionary change.

How do tides affect marine ecosystems?

Tides, caused by gravitational forces, significantly influence marine systems.

What happens to water's density as it cools below 4 degrees Celsius?

Water becomes less dense, causing ice to float, which is uncommon for most substances.

What is the impact of temperature on species distributions?

Temperature provides broad constraints for species distributions along north-south axes.

What is the relationship between metabolism and temperature regulation in mammals?

Mammals can regulate body temperature through metabolism, unlike reptiles.

What happens to plants' stomata in dry environments?

Plants often keep their stomata closed to preserve water, which limits photosynthesis.

What are the two types of ecological interactions emphasized at different levels?

Interactions are emphasized at the population and community scales.

What is the solubility of O2 in water?

0.01 L/L

What percentage of the atmosphere is composed of O2?

21%

How does temperature affect the solubility of O2 in water?

As water heats, the solubility of O2 decreases.

What type of water has higher oxygen concentrations?

Moving water has higher oxygen concentrations than deep, still water.

What causes still water to smell like sulfur?

Anaerobic decomposition.

Where does all the nitrogen in your body come from?

Legumes.

What determines the availability of ions in water?

The underlying geography, such as limestone having more calcium than granite.

What role do H+ ions play in aquatic systems?

They contribute to pH change and are regulated by bicarbonate ions.

What are the five independent factors that form soils?

Parent material, climate, biotic factors, topography, and time.

What is the relationship between soil structure and elevation?

Thinner soils exist on high elevational points, while richer soils exist in valleys.

What is the significance of aluvium in soil?

Aluvium makes low soils rich during flooding.

What are the three particle sizes in soil?

Clay (<0.002 mm), silt (0.002-0.05 mm), sand (>0.05 mm).

How does climate affect the physical template of ecosystems?

Climate variation is the most important factor influencing the physical template.

What are the most critical measures of climate?

Average temperature and average precipitation.

What geographic feature influences vegetation in Des Moines?

The tallgrass prairie climate with little topography and mineral-rich soil from glaciers.

What is the effect of Hadley Cells on global climate?

They create global patterns of air circulation and influence desert and rainforest distribution.

What is the Coriolis effect?

Air masses and moving objects deflect right in the Northern Hemisphere and left in the Southern Hemisphere.

What is the rain shadow effect?

It causes deserts on the east sides of mountain systems due to moisture being deposited on the windward side.

How does altitude affect air temperature?

Air is thinner and oxygen molecules are spread further apart at higher altitudes.

What is the euphotic zone in the ocean?

The depth of the ocean where plankton is found.

What is the aphotic zone in the ocean?

The area where the ocean becomes a desert except for chemosynthetic organisms.

What is the significance of upwellings in ocean currents?

They draw nutrients from deeper ocean layers to the surface, supporting marine life.

What is the temperature profile of lakes during spring overturn?

The top water turns over the bottom water, resuspending benthic nutrients.

What defines maritime climates?

They are near large bodies of water, resulting in cooler summers and warmer winters.

What is podsolization?

A process under temperate conditions where clays lose their cations, leading to infertile soils.

What is laterization?

A process in warm, wet climates where clays break down and leach silica, leaving behind aluminum and iron.

What determines species distributions across the Earth?

Climate, topography, and soils.

What are biomes?

Systems with very similar plant forms, driven by climate.

What happens at the margins of biomes?

Biomes grade into one another.

What does Whittaker's Biome Concept illustrate?

The relationship between climate and biome distribution.

What does Walter's scale equate?

20 mm of precipitation with 10 degrees C in temperature.

What is a major characteristic of temperate deciduous forests?

Pronounced seasonality in both precipitation and temperature.

Why do woody plants in temperate deciduous forests lose their leaves?

To conserve energy during winter when water is not bioavailable.

What biome is characterized by grasses being superior competitors when water is unavailable?

Temperate grassland.

What is a defining feature of Mediterranean shrubland?

Monsoonal precipitation with consistent temperature.

What adaptation do cacti have in subtropical deserts?

They do not have leaves.

What type of forest is characterized by coniferous trees?

Boreal forest.

What is a major feature of the tundra biome?

Presence of lichens and other low-lying plants.

What is the condition of water availability in tropical rainforests?

Water is in oversupply.

What is Shelford's law of tolerance?

Species distributions are constrained to certain ranges of abiotic conditions.

What are specialists and generalists in terms of species tolerance?

Specialists (steno-) tolerate narrow conditions; generalists (eury-) tolerate wide conditions.

What is the difference between allochthonous and autochthonous systems in freshwater habitats?

Allochthonous systems receive nutrients from outside; autochthonous systems generate nutrients internally.

What are the three zones of freshwater systems?

Littoral, benthic, and planktonic.

What is acclimation in response to environmental change?

A reversible change in morphology or physiology within an individual.

What is adaptation in the context of species traits?

A permanent change in a trait due to natural selection over generations.

What is the wilting point in soil water potential?

The point at which a plant can no longer support water pressure within its cells.

How do plants acquire water from soil?

Through osmosis and active transport of ions.

What is the tension-cohesion theory of water?

It describes how evaporation creates a gradient that pulls water into the xylem.

What adaptations do plants have to reduce water loss?

Closing stomata, using hairs or spines, and accumulating waxes in leaf cuticles.

What is a cladophyll?

A leafless photosynthetic stem that reduces water loss.

What shifts in root/shoot growth strategies can occur in nutrient-poor soils?

Changes can be both acclimations (phenotypic) and adaptations (genotypic).

What is the role of Rhizobium in legumes?

Rhizobium bacteria in legume root nodules convert atmospheric nitrogen (N2) into usable forms like NH4+ or NO3-.

Why is crop rotation beneficial for soil health?

Rotating corn and soybeans helps replenish nitrates in the soil, improving nutrient availability.

What is mycorrhizal infection?

A fungal infection of plant roots that increases surface area for nutrient uptake and provides sugars to the fungi.

What is the compensation point in photosynthesis?

The light intensity at which the rate of photosynthesis equals the rate of respiration, allowing for net sugar production.

What are the three pathways of photosynthesis?

C3, C4, and CAM (Crassulacean acid metabolism) are the three pathways, each adapted to different environmental conditions.

How do C4 and CAM photosynthesis differ from C3?

C4 and CAM are adaptations to water stress, with C4 using a two-step process and CAM separating processes between day and night.

What is the Bohr effect?

The phenomenon where low carbon dioxide concentration increases hemoglobin's oxygen retention, while high concentration promotes oxygen release to tissues.

What adaptations do osmoregulators have in aquatic ecosystems?

Osmoregulators maintain salt and water balance through specialized organs like gills and kidneys, adjusting to their environment.

How do saltwater fish manage salt balance?

Saltwater fish excrete excess salts through their gills while taking in single charge ions to match their blood's sodium concentration.

What is metabolic water and its significance for desert animals?

Metabolic water is produced during the oxidation of glycogen and helps sustain animals like the kangaroo rat in arid environments.

What is the Long Loop of Henle and its function?

The Long Loop of Henle in kangaroo rats allows for efficient water reabsorption, enabling them to conserve water while excreting concentrated urine.

What is bradycardia in diving animals?

Bradycardia is the reduction of heart rate in diving animals, which conserves oxygen and enhances delivery to working cells.

What is Allen's Rule?

Allen's Rule states that animals in warmer climates tend to have longer extremities to increase surface area for heat dissipation.

What are poikilotherms and homeotherms?

Poikilotherms have body temperatures that vary with the environment, while homeotherms maintain a constant body temperature.

What is the significance of countercurrent exchange systems?

Countercurrent exchange systems allow for efficient heat retention in animals, maintaining core body temperature despite environmental changes.

What is the difference between directional, stabilizing, and disruptive selection?

Directional selection shifts trait distribution, stabilizing selection narrows it, and disruptive selection favors extremes, potentially leading to speciation.

What is the definition of fitness in evolutionary biology?

Fitness is the proportionate contribution an individual makes to the next generation, often measured by reproductive success.

What is the role of natural selection in evolution?

Natural selection drives the differential success of organisms based on heritable traits that enhance survival and reproduction.

What is the outcome of natural selection?

The outcome is adaptations, which are traits that enable organisms to thrive in their environments and are genetically determined.

What adaptations do desert animals use to cope with thermal variation?

Desert animals utilize behavioral thermoregulation, metabolic water production, and physical adaptations to manage heat and conserve water.

How do halophytes adapt to saline environments?

Halophytes are plants that can thrive in high salinity conditions, often by excreting excess salt through specialized glands.

What is evolution?

The change in gene frequency over time.

What are the two types of speciation?

Allopatric speciation (species separated physically) and sympatric speciation (species together but different due to resource use).

What does the suffix 'patric' refer to in biological terms?

Habitat.

What is a prezygotic isolating mechanism?

Factors that prevent mating due to differences in colors, songs, pheromones, etc.