Ecology Exam 1 Material

Ecology

The study of the distribution and abundance of organisms and their relationships with their environments.

Amphibian decline

The global trend of diminishing amphibian populations during the 80s and 90s, affecting various species.

Biological Indicators

Species that indicate the health of an ecosystem, often highlighting environmental changes.

Ribeiroia ondatrae

A trematode flatworm parasite implicated in causing deformities in amphibians.

Acclimation

Short-term and reversible changes organisms make in response to environmental conditions.

Adaptation

Long-term, often irreversible changes that improve an organism's fitness in its environment.

Independent Variable

The factor that is changed or controlled in a scientific experiment to test its effects on the dependent variable.

Dependent Variable

The factor that is measured in an experiment, changing in response to the independent variable.

Experimental Control

A standard for comparison in an experiment that is not subjected to the experimental treatment.

Hypothesis Testing

The process of making predictions based on a hypothesis and testing whether the observed results support or reject it.

Pacific Decadal Oscillation (PDO)

A long-term decadal climate pattern in the Pacific Ocean indicating temperature changes.

Weather

Current conditions such as temperature, precipitation, humidity, and cloud cover.

Climate

Long-term average of weather conditions over decades, including daily and seasonal cycles.

Greenhouse gases

Gases in the atmosphere that absorb and reradiate infrared radiation, vital for maintaining Earth's temperature.

C02

H20

CH4

Coriolis Effect

The deflection of winds caused by Earth's rotation, influencing global wind patterns.

Evapotranspiration

Water loss from soil evaporation and plant transpiration, affecting air temperature and moisture.

Salinity

The concentration of salt in water, affecting water density and movement.

Rain shadow effect

A phenomenon where one side of a mountain receives high precipitation while the leeward side is dry.

Albedo

The amount of solar radiation a surface reflects; lighter surfaces have higher albedo.

Upwelling

The process where deep ocean water rises to the surface, bringing nutrients and affecting marine ecosystems.

Biome

A large-scale terrestrial community shaped by the physical environment, characterized by dominant plant growth forms.

Convergence

The evolution of similar growth forms in response to similar selection pressures.

Deciduous

Tree species that lose their leaves seasonally.

Succulent

Plants with thick, fleshy tissues that store water.

Eutrophication

The process of nutrient enrichment in water bodies, often leading to excessive growth of algae.

Permafrost

Soil that remains frozen year-round, often found in tundra biomes.

Lotic ecosystems

Freshwater ecosystems such as streams and rivers, characterized by flowing water.

Lentic ecosystems

Freshwater ecosystems such as lakes and still waters, characterized by standing water.

Photic zone

The upper layer of a water body that receives sufficient sunlight for photosynthesis.

Zooplankton

Small drifting organisms in water, including tiny animals and immature forms of larger animals.

Benthic zone

The lowest level of a water body, including the sediment surface. Sea stars, clams, coral, worms, deep sea scavengers

Riparian vegetation

Plant life situated along riverbanks and lake shores, critical for ecosystem health.

Biomes defined by evolved plant growth forms

Plants are used to categorize terrestrial biomes due to their morphological responses to the environment.

Thermal Extremes

Refers to the extreme temperatures that organisms may encounter in their environment.

Acclimatization

A short-term, reversible physiological response of an organism to changes in the environment.

Acclimation

A genetically-based physiological response typically used by plant ecologists regardless of environmental condition.

Ectotherms

Organisms that regulate body temperature primarily through energy exchange with the external environment.

Endotherms

Organisms that generate internal heat, primarily birds and mammals, to maintain their body temperature.

Albedo (α)

A measure of how much sunlight is reflected by a surface, which can impact a plant's thermal regulation.

Osmotic Potential (Ψo)

The potential energy of water that moves from a region of high solute concentration to low concentration.

Energy Balance

The relationship between energy intake and energy expenditure in plants and animals.

Pressure Potential (Ψp)

The potential energy of water that flows from an area of higher pressure to one of lower pressure.

Maritime vs Freshwater Teleosts

Marine teleosts lose water and gain salts from drinking seawater, while freshwater teleosts gain water and excrete excess solutes.

Autotrophs

Organisms that assimilate energy from sunlight (photosynthesis) or inorganic compounds (chemosynthesis) and convert it to chemical energy.

Heterotrophs

Organisms that obtain energy by consuming organic compounds from other organisms. (Predators, parasites, detrivores)

Detritivores

Heterotrophs that consume nonliving organic matter, such as earthworms and soil fungi.

Parasites

Heterotrophs that consume live hosts without necessarily killing them.

Predators

Organisms that capture and consume live prey animals.

Photosynthesis

The process by which autotrophs convert sunlight and inorganic materials into chemical energy, primarily producing glucose and oxygen.

RuBisCO

The key enzyme in photosynthesis and the most abundant enzyme on earth.

Photorespiration

A process that occurs when RuBisCO binds to oxygen instead of carbon dioxide, resulting in energy loss.

C3 Plants

Plants that utilize the C3 pathway for photosynthesis, accounting for about 90% of Earth's plants. Only use rubisco to fix carbon dioxide, resulting in a three-carbon compound during the process. Has a significant amount of photorespiration and least water-use efficient. Essentially all trees.

C4 Plants

Plants that utilize the C4 pathway to minimize water loss and photorespiration, accounting for about 5% of Earth's plants. Use Rubisco and PEP carboxylase for carbon fixation, allowing them to efficiently photosynthesize in high-temperature environments. Has an advantage in low C02.

CAM Plants

Plants that uptake CO2 at night and perform photosynthesis during the day, also accounting for about 5% of Earth's plants. Use PEP Carboxylase to fix carbon dioxide into four-carbon compounds, which are then converted to sugars during the day, minimizing water loss. Use rubisco as the enzyme for the Calvin cycle during the day, allowing them to thrive in arid conditions.

Nutrient Limitations

Factors, particularly nitrogen and phosphorus, that limit photosynthetic growth and affect herbivore attraction.

Energy Tradeoffs

The balance between the ease of acquiring food versus its calorie or nutrient value.

Adaptations for Finding Food

Features that enhance an organism's ability to find and acquire nutrients, such as mobility and mouthpart specialization.

Herbivores

Organisms that consume plants, typically characterized by longer digestive tracts for breaking down fibrous materials.

Ecology

The study of interactions between organisms and their environment.

Evolution

Change in allele frequency within a population over time.

Allele

Different forms of a gene that can exist at a specific locus.

Genotype

The genetic constitution of an individual organism.

Phenotype

The physical expression of a genotype, including traits such as morphology and behavior.

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Genetic Drift

A mechanism of evolution that involves random changes in allele frequencies in a population.

Gene Flow

The transfer of alleles or genes from one population to another.

Adaptive Evolution

Evolution that results in a better fit between organisms and their environments.

Speciation

The formation of new and distinct species in the course of evolution.

Mass Extinction

A period in which a significant number of species die out in a relatively short time.

Mutation

A change in the DNA sequence of a gene.

Descent with Modification

A key concept in evolutionary theory, where species change over time, giving rise to new species.

Mechanisms of Evolution

1. Mutation 2. Natural Selection 3. Genetic Drift 4. Gene Flow

Two ways vegetation affects climate:

1. Transpiration (adds water vapor → cooling/precipitation)

2. Albedo (reflects more/less sunlight → affects temperature)

Global Wind Patterns

Air movement patterns driven by the uneven heating of the Earth's surface, influencing weather and climate. These patterns include trade winds, westerlies, and polar easterlies.

• Hadley Cell (0–30°)

• Ferrel Cell (30–60°)

• Polar Cell (60–90°)

Pelgic Zone

Refers to the open ocean area that is not near the coast or the ocean floor. It is characterized by its deep waters and supports a variety of marine life, including plankton, fish, and larger predators. Fish with adaptations to high pressure and low light. Fish, marine animals, plankton, jellyfish

Flowing water system zones (lotic ecosystems)

Main Channel - The flowing water of the river, with varying velocities and depths.(swimming organisms)

Benthic Zone - sediment at the bottom (larve)

Hyporheic Zone - a region of water that flows beneath the riverbed, influencing water quality and habitat.

Ocean Zones

Photic

Pelagic

Benthic

4 factors that impact photosynthesis rate

Nutrients available

Light amount

Temperature

Precipitation

4 Components of Water potential

Gravity

• Gravity potential (Ψg): Water flows downhill, following a gradient of

potential energy (gravitational potential).

• Pressure potential (Ψp): Water flows from an area of higher pressure

to lower (pressure or turgor potential).

• Osmotic potential (Ψo): Water flows from a region of high

concentration (low solute concentration) to a region of low

concentration (high solute concentration).

• Matric potential (Ψm): Energy associated with attractive forces on

surfaces of large molecules in cells or on surfaces of soil particles

Temperature response at high vs low temperature

• Low temperature: reaction rates are slow (enzymes work slowly), so physiological processes are limited

• High temperature: enzymes denature and cellular processes break down