Principles of ecology Exam 1
A physiological study of a single red wood tree as it develops from seed to adult would require several generations of scientists to work together along the long life span of this species. This would be an example of an ecological study at the level of: the individual
Along an altitudinal gradient, Humboldt described changes in vegetation associated with temperature differences known as "Thermal belts". However, topography can also result in a horizontal gradient in rainfall. Specifically, rainfall is expected to be greater on the windward side of a mountain range than on the leeward side. This pattern is known as a “ Rain shadow effect", These differences in precipitation primarily result from abiabatic cooling and heat conduction
Temperature and precipitation change along latutudinal gradients with critical implications for the distribution of most types of organisms. These gradients are caused by ? Direct and persistent longwave radiation coming in from the sun into the polar regions.
What are the main factors considered when classifying habitats in terrestrial biomes ? percipitation and temperature
Why is studying climate important in ecology ? propose one short sentence
Climate determines organism distribution and ecosystem interactions, which can influence biodiversity and ecological processes.
Define the terms
Population-groups of same species that occupy a given area.
Community-all populations of different species living and interacting within an ecosystem
Ecosystem-physical conditions and array of organisms that co-exist within its confines
Land-scape-area of land or water composed of a patchwork of communities and ecosystems.
Biome-broad scale regions dominated by similar types of ecosystem
Biosphere- thin layer surrounding the earth that supports all life
How do ecology and environmentalism differ? In what way does environmentalism depend on the science of Ecology? Ecology is the scientific study of relationships between organisms and their environment. Environmentalism is rooted in family, meaning that environmentalism holds an emotional response.
How might including the abiotic environment within the framework of the ecosystem help ecologists achieve the basic goal of understanding the interaction of organisms with their environment? Broadly speaking, the ecosystem consists of the living (biotic) and the physical/non living (abiotic) , they interact with each other as a system,
What is a hypothesis? What is the role of hypotheses in Science?
Hypothesis- A proposed answer to the question. The hypothesis must be testable through observations and experiments.
An ecologist observes that the diet of a bird species consists primarily of large grass seeds (as opposed to smaller grass seeds or the seeds of other herbaceous plants found in the area). He hypothesizes that the birds are choosing the larger seeds because they have a higher concentration of nitrogen than do other types of seeds at the site. To test the hypothesis, the ecologist compares the large grass seeds with the other types of seeds, and the results clearly show that the large grass seeds do indeed have a much higher concentration of nitrogen. Did the ecologist prove the hypothesis to be true? Can he conclude that the birds select the larger grass seeds because of their higher concentration of nitrogen? Why or why not? He is using a models, while it shows they are choosing the nuts with higher levels of nitrogen it doesn’t address why. It could also be the fact the bird sees a larger seed, and assumes its a higher amount of nutrients , rather than the small one, NOT necessarily the nitrogen itself.
What is a model? What is the relationship between hypotheses and models?
Model- Predict behavior or response using a set of explicit assumptions. Models can aid in hypothesis testing to eliminate incorrect ideas.
Given the importance of ecological research in making political and economic decisions regarding current environmental issues such as global warming, how do you think scientists should communicate uncertainties in their results to policy makers and the public? Environmental Science. ES examines the impact on humans on the natural world, it is a broader framework to understanding ethical dimensions.
Diversity - The variety of different species within a given area or ecosystem.
Risk - The possibility of loss or harm, often related to the survival of species or ecosystems under various threats.
Endemism - The ecological state of a species being unique to a defined geographic location, not found naturally anywhere else.
Extinction - The cessation of existence of a species, leading to its permanent disappearance from the planet.
Organisms are distributed variably across large states in specialized habitats. They face various threats and risk factors—such as habitat destruction, climate change, and invasive species—that impact their populations and ecosystems, necessitating effective conservation efforts.
Topography-physical structure of the landscape
Mechanism behind thermal belts : atmospheric thickness
Leeward:Dry air descends and warms, promotes evaporation
Windward: Rising air cools and condenses
Rain shadow
CA current system- CA current(southward), CA undercurrent(northward), Davidson current (northward, in winter)
Upwelling: wind driven movement of surfave waters bring deep, cold, nutrient rick water to the surface. This correlates with primary productivity, small scale patterns, eddies.
Patterns in ecology refer to the recurring characteristics and distributions of organisms, populations, and communities in relation to environmental factors, while processes are the underlying mechanisms that drive these patterns, such as energy flow and species interactions.
Linking the two helps understand how environmental changes impact ecosystems. For example:
Condor Reintroduction: Aimed at restoring the population of California condors, this effort highlights the decline in biodiversity and the necessity to protect their habitats for food and breeding. Monitoring post-reintroduction patterns informs future management strategies.
Dam Removal: This practice supports river restoration by reinstating natural hydrological processes, promoting habitat recovery for aquatic species, and improving biodiversity by allowing for natural movement and sediment transport.
Weather- combination of temperature, humidity, precipitation and other atmospheric conditions occurring at a specific place and time.
Climate- long term average pattern of weather and may be local, regional, or global.
albedo-quantity of shortwave radiation reflected by a surface is a function of its reflectivity.
Albedo is expressed as a propprtion (o-1.0) of the shortwave radiaton striking a surface that is reflected and differs for different surfaces.
Greenhouse effect: The warming of Earth's surface caused by the trapping of heat by greenhouse gases in the atmosphere, which absorb and emit radiation.
Greenhouse gases: Gases such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) that contribute to the greenhouse effect by allowing sunlight to enter the atmosphere while preventing some of the heat from escaping back into space.
net radiation- difference between the incoming shortwave ( solar) radiation and outgoing longwave (terrestrial) radiation
OPTIMUM, TOLERANCE, AND INTOLERANCE ZONES IN ORGANISMS
Explanation: Organisms perform differently along environmental gradients, with specific zones where they thrive (optimum), survive (tolerance), or fail to survive (intolerance). These zones are critical for understanding how organisms adapt to their environments and predict their performance under varying conditions.
Key Points:
Optimum zones represent the conditions where an organism performs best.
Tolerance zones are ranges where organisms can survive but may not thrive.
Intolerance zones are conditions where organisms cannot survive, leading to death.
Environmental gradients, such as temperature or radiation, influence these zones.
Understanding these zones helps predict organism distribution and survival.
EARTH'S AXIAL TILT AND SOLAR RADIATION DISTRIBUTION
Explanation: The axial tilt of the Earth determines the amount of solar radiation received at different latitudes, influencing climate and ecological conditions. The tropics receive consistent radiation year-round, while temperate zones experience seasonal fluctuations due to the Earth's tilt.
Key Points:
The axial tilt causes variations in solar radiation across latitudes.
Tropics receive consistent solar radiation daily, leading to stable climates.
Temperate zones experience seasonal changes in radiation intensity.
Higher latitudes have more dramatic changes in radiation due to the angle of sunlight.
These variations impact temperature, precipitation, and ecological processes.
HADLEY CELLS AND ATMOSPHERIC CIRCULATION
Explanation: Hadley cells are large-scale atmospheric circulation patterns between the equator and 30° latitude, driven by solar radiation and Earth's rotation. They play a crucial role in distributing heat and moisture, creating wet tropics and dry subtropical regions.
Key Points:
Hadley cells form due to rising warm, moist air at the equator and descending dry air at 30° latitude.
Earth's rotation causes air movement to deflect, creating trade winds.
Rising air cools and precipitates, making the tropics wet and humid.
Descending air at 30° latitude creates arid regions, such as deserts.
Hadley cells influence global weather patterns and climate zones.
EL NIÑO, LA NIÑA, AND OCEAN PRODUCTIVITY
Explanation: El Niño and La Niña are climate phenomena that alter oceanic and atmospheric conditions, significantly impacting marine productivity and global weather patterns. El Niño weakens trade winds, reducing nutrient upwelling, while La Niña strengthens them, enhancing productivity.
Key Points:
El Niño weakens winds, causing warm, nutrient-poor water to dominate, reducing photosynthesis and marine productivity.
La Niña strengthens winds, increasing nutrient-rich upwelling and boosting productivity.
El Niño leads to extreme weather, such as heavy rains in Latin America and droughts in Oceania.
La Niña can cause stronger storms and colder ocean temperatures.
Both phenomena have global ecological and economic impacts, including effects on fisheries and agriculture.
THERMAL BELTS AND ALTITUDINAL ECOLOGY
Explanation: Thermal belts describe temperature and precipitation variations with altitude, influencing vegetation and species distribution. These gradients create unique ecological niches, promoting biodiversity and speciation, especially in mountainous regions.
Key Points:
Temperature and precipitation vary with altitude, creating distinct ecological zones.
Vegetation types change with altitude due to these climatic differences.
Thermal belts contribute to high biodiversity in mountainous regions.
They influence crop distribution and agricultural practices.
These gradients drive speciation in organisms like birds and frogs.
THERMOHALINE CIRCULATION AND GLOBAL OCEAN CURRENTS
Explanation: Thermohaline circulation is a global ocean current system driven by temperature and salinity differences, playing a key role in regulating Earth's climate. Cold, dense water sinks at the poles, driving deep ocean currents that redistribute heat and nutrients worldwide.
Key Points:
Cold, salty water at the poles sinks due to high density, initiating circulation.
This process moves water across the globe, connecting ocean basins.
Thermohaline circulation regulates global climate by redistributing heat.
Melting polar ice caps can disrupt this system, with significant climate consequences.
It also impacts nutrient cycling and marine ecosystems.
LIGHT PENETRATION IN WATER AND PHOTOSYNTHESIS
Explanation: Light penetration in water decreases with depth, affecting photosynthesis and the distribution of aquatic life. The availability of light determines the productivity of photosynthetic organisms, which form the base of aquatic food webs.
Key Points:
Light intensity decreases exponentially with water depth.
Different wavelengths of light penetrate to varying depths, with red light absorbed first and blue light penetrating deepest.
Photosynthesis is limited to the photic zone, where sufficient light is available.
Deeper waters have reduced primary productivity due to low light levels.
Light penetration is influenced by water clarity and suspended particles.
THERMAL INERTIA AND HEAT RETENTION IN ORGANISMS
Explanation: Thermal inertia refers to an organism's ability to retain heat, influenced by its size, mass, and insulation. Larger organisms with greater mass retain heat better, while smaller organisms lose heat quickly, affecting their thermal regulation strategies.
Key Points:
Thermal inertia is higher in larger organisms due to greater mass.
Insulating materials like feathers, fur, or fat enhance heat retention.
Smaller organisms lose heat rapidly and require higher metabolic rates to maintain body temperature.
Thermal inertia affects an organism's ability to survive in extreme temperatures.
Succulent plants, like cacti, use their mass to regulate temperature and retain heat.
DESIGNING EXPERIMENTS AND INTERPRETING GRAPHS
Explanation: Designing experiments involves identifying variables, creating a sampling strategy, and visualizing expected results. Interpreting graphs requires understanding axes, trends, and their implications for biological or ecological processes.
Key Points:
Clearly define independent and dependent variables in an experiment.
Use appropriate sampling methods, such as measuring light at different depths.
Graphs should clearly represent relationships between variables (e.g., depth vs. light intensity).
Understand how to describe trends, such as light decreasing with depth.
Relate experimental findings to biological processes, like photosynthesis or species distribution.