Comprehensive Study Guide for Ecology and Environment: Chapters 5-8
Chapter 5: Keynotes
Biotic Potential: Defined as the specific number of offspring produced by a given species.
Carrying Capacity: Represents the maximum population size of a species that a specific environment can sustain indefinitely. This limit is determined by the availability of necessary resources, including food, water, habitat, and other essentials.
Colonial: Refers to organisms that live in colonies composed of individuals that are genetically identical to one another. An example of this is coral.
Continental Islands: These are islands that constitute part of a continental land mass. They are situated relatively close to continents on the continental shelf. Some of these islands may have been physically connected to the mainland in the past.
Examples: Palawan, Philippines and Viti Levu, Fiji.
Coral Bleaching: The process where corals lose their zooxanthellae (which provide the coral's color) when subjected to environmental stress, particularly elevated temperatures.
Demography: The specific statistical study of populations, with a particular focus on human populations.
Epiphytes: Plants (or occasionally animals) that attach themselves to the surfaces of other plants to obtain physical support. They do not derive nutritional support from the host plant.
Examples: Most orchids and the bird’s nest fern.
Indigenous Species: These are species that arrived on an island before the arrival of mankind, also known as native species. this category includes:
Endemic Species: Species unique to a specific location.
Other Native Species: Species that occur naturally in the location but also exist in other places.
Introduced Species: In contrast to indigenous species, these are species brought to a location by the actions of mankind.
Mutualism: A specific type of symbiosis wherein both partners in the relationship benefit. Frequently, one partner provides food or nutrients while the other provides different necessary nutrients.
Examples: Coral polyps and zooxanthellae; trees and mycorrhizae.
Oceanic Islands: Islands located far from continents that are not part of the continental crust. These are typically formed by undersea volcanic activity.
Parasitism: A type of symbiosis where one partner, the parasite, derives nourishment from the other, known as the host.
This relationship usually involves the parasite living either inside or on the surface of the host.
Examples: Fleas or the deep sea anglerfish.
Pioneer Species: A plant or animal that colonizes an area quickly during the processes of primary or secondary succession. They take advantage of new environmental conditions but typically do not persist into the later stages of succession.
Examples: Lichens in primary succession; papaya in secondary succession.
Samples: Specific portions of a population taken for analysis. Scientists aim to collect representative and statistically sound samples to ensure accurate population estimates.
Species Migration: The successful establishment of a population of a species in a new geographic location.
Succession (Primary and Secondary): Refers to the changes over time in the species present in a specific place. This process is distinct from zonation.
Symbiosis: Literally meaning "living together," donde the involved partners are called symbionts. These partnerships are often based on nutrition. Depending on the benefit to the partners, they are classified as:
Mutualism: Both benefit.
Commensalism: One benefits, the other is unaffected.
Parasitism: One benefits at the expense of the other.
Transect: A long, narrow study area usually established along an environmental gradient to observe zonation patterns. A transect line (a rope or tape measure) is used to define specific points for study.
Zooxanthellae: These are brownish algae, typically dinoflagellates, that live in a symbiotic relationship with corals and other marine animals. Some animals host green partners called zoochlorellae.
Etymology: "Xanth" refers to the algal pigment xanthophylls, and "chlor" refers to chlorophyll.
Chapter 5: Questions & Discussion
How do native and introduced species migrate to islands?
Native Species: Reach islands through natural means such as wind, water currents, flying, or rafting on floating vegetation.
Introduced Species: Are brought to islands by humans, either intentionally or accidentally, through travel, trade, or various forms of transportation.
Memory Tip: NATIVE = natural; INTRODUCED = human help.
Why is the population growth curve useful?
A population growth curve allows scientists to track how a population changes over time, indicating if it is growing, stable, or declining. This data helps in predicting future population trends.
Memory Tip: CURVE = see growth patterns.
Why does changing the environment also change the carrying capacity for a species?
Because carrying capacity is reliant on resources like food, water, shelter, and space, any environmental change that alters these resources will subsequently increase or decrease the number of individuals the area can support.
Memory Tip: MORE RESOURCES = more organisms.
How are methods of population sampling used to measure changes in population size?
Scientists utilize methods such as quadrats, transects, and mark-recapture studies to estimate the total population size and monitor changes over time without the need to count every single organism.
Memory Tip: Sample a little, estimate a lot.
How is the coral-zooxanthellae symbiosis the basis for all food webs in coral reefs?
The zooxanthellae algae reside inside the coral tissues and perform photosynthesis to produce food. This food nourishes the coral, providing the primary production that supports the entirety of the coral reef food web.
Memory Tip: Algae feed the reef.
How does primary succession create an ecological community from bare surfaces on land or in the ocean?
Primary succession starts on surfaces lacking soil. Pioneer species—such as lichens, algae, or bacteria—colonize first. These organisms gradually create soil and establish environmental conditions that allow larger plants and animals to move in and form a community.
Memory Tip: Bare rock life.
Why is secondary succession generally faster than primary succession?
Secondary succession occurs faster because soil nutrients, seeds, and occasionally surviving organisms remain after a disturbance, facilitating a quicker ecosystem recovery.
Memory Tip: Soil already there.
Chapter 6: Keynotes
Biomass: The total dry weight of a specific group of organisms. This term is most frequently applied to specific trophic levels, such as the biomass of herbivores.
Biome: A large-scale classification of vegetation, primarily used on a global scale for continental regions.
Examples: Grassland or desert.
Carnivore: An animal that consumes live animals (known as a predator) or dead meat (known as a scavenger).
Examples: Spiders, brown tree snake.
Etymology: "Carni" = meat; "Vore" = to eat.
Decomposers: Technically refers only to fungi and bacteria that break down complex organic matter from dead organisms into simpler organic molecules and inorganic molecules. The term is sometimes used broadly to include all organisms that feed on dead organic matter, such as detritivores.
Detritus/Detritivore: An animal that feeds specifically on detritus (dead organic matter).
Examples: Earthworm or sea cucumber.
Ecosystem: Consists of a biological community (or multiple interacting communities) combined with their physical environment.
Examples: Coral reefs, wetlands, forests.
Energy: Defined as "the ability to do work," whether that work is a chemical conversion or muscle movement. Animals obtain energy from food; primary producers store energy from the sun via photosynthesis. For humans, this also encompasses fuels and electricity.
Environmental Gradient: A shift in an abiotic factor from one location to another.
Examples: Salinity changes along an estuary; light level changes from a forest clearing into the deep forest.
Eutrophication: The addition of nutrients to aquatic ecosystems and the resulting successional changes in those communities.
While it occurs naturally over long timeframes, the term often refers to rapid changes caused by human pollution, such as agricultural runoff and sewage.
Food Web: A diagram of connections between organisms in an ecosystem that illustrates "who eats whom."
Herbivore: An animal that eats plants or other primary producers.
Examples: A caterpillar eating a leaf; a human eating a salad.
Etymology: "Herb" = of plants; "Vore" = to eat.
Limestone Forest: A forest type found on raised limestone islands, such as those in the southern Mariana Islands and the Rock Islands of Palau.
Photosynthesis: The chemical pathways used by plants to trap solar energy and produce sugars from carbon dioxide. This occurs only in light and within the pigmented cells of primary producers. It involves the uptake of carbon dioxide and the release of oxygen.
Phytoplankton: Algae that drift within marine or freshwater environments; they usually have very limited swimming capabilities.
Respiration: The metabolic pathways organisms use to release energy from fuel molecules (like sugar). This occurs constantly in all organisms living in oxygenated environments. It involves absorbing oxygen and releasing carbon dioxide.
Productivity (Gross/Net): The measure of carbon or energy added to the biomass of an individual or group (trophic level).
Net Productivity: Excludes the carbon and energy lost through the process of respiration.
Gross Productivity: The total amount of carbon and energy taken in before accounting for respiration losses.
Trophic Level: A specific position in a food chain or food web.
Chapter 6: Questions & Discussion
Why does the amount of biomass (and usable energy) decrease as we move up the food chain from producers to top carnivores?
At each trophic level, most energy is consumed for life processes or lost to the environment as heat. Consequently, only a small fraction (approximately ) is transferred to the next level.
Memory Tip: "10% moves up."
How do decomposers recycle dead plants and animals into fertilizer for plants?
Decomposers like fungi and bacteria break down dead organisms and waste products, which releases nutrients back into the soil. These nutrients are then absorbed by plants as fertilizer.
Memory Tip: "Dead stuff nutrients."
Why are food webs more complex and more realistic than food chains?
Food webs represent the diverse feeding relationships in an ecosystem, acknowledging that most organisms both eat and are eaten by more than one species.
Memory Tip: "Web = many connections."
How do producers make carbohydrates through photosynthesis?
Producers utilize energy from sunlight to synthesize carbohydrates (glucose) from carbon dioxide and water, releasing oxygen in the process.
Equation:
Memory Tip: "Sun + Water + CO2 = Sugar."
Why is most of the biomass we consume burned for energy through respiration?
Organisms use respiration to chemically break down food molecules using oxygen, which releases the energy required for life. The byproducts of this process are carbon dioxide and water.
Equation:
Memory Tip: "Food + Oxygen = Energy."
How can some simple organisms turn nitrogen in the air into fertilizer in the soil?
Nitrogen-fixing bacteria convert atmospheric nitrogen gas into usable forms, such as ammonia and nitrates, which plants need for growth.
Memory Tip: "Nitrogen-fixing bacteria = natural fertilizer factory."
Chapter 7: Keynotes
Canopy (of a forest): The layer created by the crowns (leaves and branches) of trees. Tall forests may have an upper canopy of tall trees and a lower canopy of shorter trees.
Community-Based Conservation: Conservation efforts that are organized and executed by local communities rather than governmental bodies.
Conservation: The careful or restricted use of renewable resources, including water, land, plants, and animals.
Ecotourism: Tourism directed toward fragile or undisturbed natural environments, designed to provide benefits to local communities while conserving the environment.
Erosion: The physical process by which wind and water wear away soil and rock.
Leaching: The process of extracting soluble materials from solids (like soil or coffee grounds) as water filters through. The resulting solution is called the leachate.
Mycorrhizae: A mutualistic association between symbiotic fungi/bacteria and plant roots.
Etymology: Greek "myco" = fungi; "rhizae" = roots.
Resource: Anything a species requires to survive and reproduce. Examples include food, water, and nesting sites; for humans, this extends to metals and fuels.
Savanna: A type of vegetation characterized by wide grasslands with scattered trees.
Soil: A complex, dynamic ecosystem and terrestrial habitat composed of clay minerals, air, water, and organic remains, constantly reworked by living organisms. An "individual soil" refers to a specific volume of soil with unique characteristics.
Stakeholder: An individual, group, or organization with a specific interest (a stake) in a situation or project.
Sustainability: The objective of managing resources so that future generations can continue to utilize them indefinitely.
Watershed: The line along hilltops where water flows in opposite directions. The term also refers to the entire land area and vegetation basin that collects water for a specific river system or reservoir.
Chapter 7: Questions & Discussion
What are the components of soil?
Soil is comprised of minerals (rock particles), organic matter (decayed organisms), water, air, and living organisms like fungi, bacteria, insects, and worms.
Memory Tip: SOIL = Rocks + Rotting stuff + Water + Air + Life.
How does soil form from bare rock?
Weathering processes break bare rock into small particles. Over time, decomposing organic matter mixes with these particles to create soil.
Memory Tip: ROCK weathering small particles + dead organisms = SOIL.
Why is soil conservation especially important in the tropics where the topsoil layer is thin?
Tropical topsoil contains the vast majority of nutrients required by plants. Because this layer is thin, heavy rains can easily wash it away, rendering the land difficult for plant growth.
Memory Tip: THIN TOPSOIL = Easy to lose, hard to replace.
How do preserving vegetation and other soil conservation methods protect reef-building corals from sedimentation?
Vegetation anchors soil and prevents erosion. When erosion is reduced, less sediment enters the ocean to cover coral reefs. This ensures corals receive the sunlight necessary for health.
Memory Tip: PLANTS HOLD SOIL Less sediment Healthy corals.
How do typhoons affect forest ecosystems?
Typhoons can uproot trees, strip leaves, break branches, and cause flooding. While damaging, these changes can also create new habitat opportunities for different plants to grow.
Memory Tip: TYPHOON = Tree damage + Habitat changes.
What are methods of forest conservation and forest restoration?
Conservation: Includes protecting existing forests, preventing illegal logging, reducing forest fires, and establishing protected areas.
Restoration: Involves reforestation (planting trees), habitat restoration, and managing invasive species.
Memory Tip: CONSERVE = Protect forests | RESTORE = Rebuild forests.
What types of ecological services are provided by functioning forest ecosystems?
Forests provide oxygen production, carbon storage, water filtration, soil protection, wildlife habitat, flood control, and climate regulation.
Memory Tip: FORESTS = Clean air, clean water, healthy wildlife, stable climate.
Chapter 8: Keynotes
Mangrove Forest: A swamp forest located in a tropical estuary.
Marsh: A wetland (freshwater or marine) dominated by grasses or grass-like vegetation.
Mitigation: Actions taken to reduce environmental damage or to replace a damaged environment with a habitat deemed equivalent.
Pneumorrhizae: Specialized roots of mangrove trees that allow the plant to obtain oxygen despite being submerged in anoxic (oxygen-depleted) mud.
Etymology: "Pneumo" = air; "Rhizae" = roots.
Swamp: A wetland (freshwater or marine) dominated by trees. This contrasts with a marsh.
Wetland: Land areas that are permanently or periodically flooded or submerged in shallow water. They must be both "wet" and "land."
Note: Coral reef flats are considered wetlands, but deep-water reefs are not.
Chapter 8: Questions & Discussion
How do the lives of plants and animals in freshwater ecosystems with flowing water differ from those in non-moving water?
Flowing Water (Rivers/Streams): Organisms must adapt to currents using streamlined bodies, strong swimming ability, or by attaching to rocks.
Non-moving Water (Ponds/Lakes): Organisms do not face strong currents and typically live among still-water vegetation.
Memory Tip: FLOWING = Adapt to currents | STILL = Calm conditions.
How can freshwater animals spend part of their lives in marine ecosystems?
Certain species migrate between the two environments at different life stages. For example, some may be born in freshwater, move to the ocean to mature, and return to freshwater to spawn.
Memory Tip: FRESH + SALT = Different homes for different life stages.
Why are wetlands’ ecological services often undervalued?
They are frequently viewed as "unused" land that could be developed. This leads people to ignore their critical roles in flood control, water filtration, and providing wildlife habitats and shoreline protection.
Memory Tip: WETLANDS = Valuable, even if they look empty.
How do mangroves serve as nurseries to support reef fisheries?
The complex root systems of mangroves provide protection and shelter for juvenile fish and crabs. These organisms grow in the safety of the mangroves before moving to open water or coral reefs.
Memory Tip: MANGROVES = Baby fish daycare.
Why can wetland conservation protect coral reefs from sedimentation?
Wetlands act as filters that trap soil, sediment, and pollutants before they reach the sea. This prevents sediment from smothering coral reefs.
How can mitigation partially compensate for the effects of development on natural ecosystems?
Mitigation involves rebuilding habitats, creating replacement wetlands, or protecting existing nearby ecosystems to reduce overall damage. While not a perfect replacement for what is lost, it lessens the development's impact.
Memory Tip: MITIGATION = Reduce and repair damage.