Ecology Exam Review

Chapter 51

• Agonistic behavior: A contest involving threats and possibly combat to determine which competitor gains access to a resource.
• Altruism: Selflessness; behavior that reduces an individual's fitness while increasing another individual's fitness.
• Associative learning: Associating one environmental feature with another.
• Behavior: Everything an animal does and how it does it.
• Circadian rhythm: A daily cycle of rest and activity.
• Circannual rhythm: A behavioral rhythm linked to the yearly cycle of seasons.
• Classical conditioning: A type of associative learning in which an arbitrary stimulus is associated with a reward or punishment.
• Cognition: The process of knowing that involves awareness, reasoning, recollection, and judgment.
• Cognitive map: A representation in the nervous system of the spatial relationships between objects in an animal’s surroundings.
• Cross fostering study: A behavioral study in which the young of one species are placed in the care of adults from another species.
• Fixed action pattern: A sequence of unlearned acts directly linked to a simple stimulus.
• Foraging: Food-obtaining behavior; includes recognizing, searching for, capturing, and eating food items.
• Imprinting: The formation at a specific stage in life of a long-lasting behavioral response to a particular individual or object.
• Innate behavior: Behavior that is developmentally fixed.
• Learning: The modification of behavior based on specific experiences.
• Migration: A regular, long-distance change in location.
• Monogamous: Referring to a type of relationship in which one male mates with just one female.
• Operant conditioning: A type of associative learning in which an animal learns to associate one of its behaviors with a reward or punishment.
• Optimal foraging: The basis for analyzing behavior as a compromise of feeding costs versus feeding benefits.
• Pheromones: In animals and fungi, a small molecule released into the environment that functions in communication between members of the same species.
• Polyandry: A mating system in which one female mates with multiple males.
• Polygamous: Referring to a type of relationship in which an individual of one sex mates with several of the other.
• Polygyny: A mating system in which one male mates with multiple females.
• Problem solving: The cognitive activity of devising a strategy to overcome an obstacle.
• Sensitive period: A limited developmental phase when certain behaviors can be learned.
• Sexual dimorphism: The extent to which males and females differ in appearance.
• Sign stimuli: An external sensory stimulus that triggers a fixed action pattern.
• Social learning: Modification of behavior through the observation of other individuals.
• Spatial learning: Modification of behavior based on experience with the spatial structure of the environment, including the locations of nest sites, hazards, food, and prospective mates.

1. Tinbergen’s four questions:

   • What stimulus elicits the behavior, and what physiological mechanisms mediate the response? (Proximate)
   • How does the animal’s experience during growth and development influence the response? (Proximate)
   • How does the behavior aid survival and reproduction? (Ultimate)
   • What is the behavior’s evolutionary history? (Ultimate)

2. Associative learning and toxic prey: Predators may learn to avoid toxic prey through associative learning by associating the prey's color or pattern with a negative experience (e.g., sickness).

3. Cross-fostering experiments: These experiments help determine the influence of environment vs. genetics by comparing the behavior of offspring raised by different parents.

4. Optimal foraging theory: This theory predicts that animals forage in a way that minimizes the costs of foraging and maximizes the benefits, such as energy intake.

5. Intersexual vs. Intrasexual selection:

   • Intersexual selection: Mate choice, where individuals of one sex (usually females) are choosy in selecting their mates from the other sex.
   • Intrasexual selection: Competition between individuals of the same sex (usually males) for mates.

Chapter 53

• Age structure: The relative number of individuals of each age in a population.
• Carrying capacity: The maximum population size that a particular environment can sustain.
• Demographic transition: The movement from high birth and death rates toward low birth and death rates, which tends to accompany industrialization and improved living conditions.
• Density dependent growth: Referring to any characteristic that varies according to an increase in population density.
• Density independent growth: Referring to any characteristic that is not affected by population density.
• Ecological footprint: The aggregate land and water area required by each person, city, or nation to produce all the resources it consumes and to absorb all the waste it generates.
• Emigration: The movement of individuals out of a population.
• Exponential population growth: Population increase under idealized conditions when food is abundant, and all individuals reproduce at their physiological capacity. Its equation is expressed as \frac{dN}{dt} = r{\text{max}}N, where N is the population size, t is time, and r{\text{max}} is the intrinsic rate of increase.
• Immigration: The influx of new individuals into a population from other areas.
• Iteroparity: Reproduction in which adults produce offspring over many years; also known as repeated reproduction.
• K-selection: Selection for life history traits that are sensitive to population density; also known as density-dependent selection.
• Logistic population growth: Population growth that levels off as population size approaches carrying capacity.
• The equation is expressed as \frac{dN}{dt} = r_{\text{max}}N(\frac{K-N}{K}), where K is the carrying capacity.
• Mark-recapture method: A sampling technique used to estimate the size of animal populations.
• Population: A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.
• r-selection: Selection for life history traits that maximize reproductive success in uncrowded environments; also known as density-independent selection.
• Semelparity: Reproduction in which an organism produces all of its offspring in a single event; also known as big-bang reproduction.
• Type I survivorship curve: A survivorship curve in which newborns, juveniles, and young adults all have high survival rates and death rates do not begin to increase greatly until old age.
• Type II survivorship curve: A survivorship curve in which the death rate is constant over the organism's life span.
• Type III survivorship curve: A survivorship curve in which newborns, juveniles, and young adults all have low survival rates and death rates decline dramatically for those individuals that survive to become adults.

1. Exponential vs. Logistic Models:

   • Exponential Growth: Assumes unlimited resources and no constraints on population size.
   • Logistic Growth: Takes into account carrying capacity and density-dependent factors that limit growth as resources become scarce.

2. Density-Dependent and Density-Independent Factors:

   • Density-Dependent Factors: Factors like competition, predation, disease, and territoriality that affect population growth based on density.
   • Density-Independent Factors: Factors like natural disasters, weather, and climate that affect population growth regardless of density.

3. Biotic and Abiotic Factors: Biotic (living) factors like predators and competitors, and abiotic (non-living) factors like temperature and rainfall, can interact to control population growth.

4. Demographic Transition: A shift from high birth and death rates to low birth and death rates, typically associated with industrialization and improved living standards.

5. Age structures: They depict the distribution of different age groups in a population, often visualized as a pyramid. These structures help predict future population growth trends.

Chapter 54

• Aposematic coloration: The bright warning coloration of animals with effective physical or chemical defenses.
• Batesian mimicry: A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators..
• Biomanipulation: An approach that uses top-down model to prevent algal blooms and restore polluted communities. (E.g. adding predatory fish).
• Character displacement: The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
• Commensalisms: A symbiotic relationship in which one organism benefits but the other is neither helped nor harmed.
• Competition: An interaction between organisms or species, in which both require a resource that is in limited supply..
• Competitive exclusion principle: The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population.
• Cryptic coloration: Camouflage that makes a potential prey difficult to spot against its background.
• Disturbance: An event, such as a storm, fire, flood, drought, overgrazing, or human activity, that changes a community by removing organisms from it or altering resource availability.
• Dominant species: Those species in a community that are the most abundant or that collectively have the highest biomass.
• Ecosystem engineer: An organism that influences community structure by creating, modifying, or maintaining physical habitat for other species.
• Ectoparasite: A parasite that feeds on the external surface of a host.
• Endoparasite: A parasite that lives within a host.
• Evapotranspiration: The evaporation of water from soil plus the transpiration of water from plants.
• Food chain: The transfer of energy and nutrients from one trophic level to another.
• Food web: A community of organisms where there are several interrelated food chains.
• Fundamental niche: The niche potentially occupied by that species.
• Herbivory: An interaction in which an herbivore eats parts of a plant or alga.
• Host: An organism on or in which a parasite lives.
• Intermediate disturbance hypothesis: The concept that moderate levels of disturbance can foster greater species diversity than low or high levels of disturbance.
• Interspecific interaction: Interactions between species.
• Invasive species: A species, often introduced by humans, that takes hold outside its native range.
• Keystone species: A species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche.
• Mullerian mimicry: A mutual mimicry by two unpalatable species.
• Mutualism: A symbiotic relationship in which both participants benefit.
• Niche: The sum of a species' use of the biotic and abiotic resources in its environment.
• Parasitism: A symbiotic relationship in which one organism (the parasite) benefits at the expense of another (the host) by living either within or on the host.
• Pathogen: An organism or virus that causes disease.
• Predation: An interaction in which one organism (the predator) kills and eats another organism (the prey).
• Primary succession: A type of ecological succession that occurs in an area where there were originally no organisms present and where soil has not yet formed.
• Realized niche: The niche actually occupied by that species.
• Relative abundance: The proportional representation of a species in a community.
• Resource partitioning: The division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species.
• Secondary succession: A type of ecological succession that occurs in an area that has been disturbed but where soil is still present.
• Species diversity: The number and relative abundance of species in a biological community.
• Species richness: The number of different species in a community.
• Succession: A process of change in the species structure of an ecological community over time.
• Symbiosis: A close relationship between two species that benefits at least one of the species.
• Zoonotic disease: A disease transmitted from animals to humans.

1. Ecological Niche and Competitive Exclusion: An ecological niche is the sum of a species' use of biotic and abiotic resources. The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same niche; one will eventually outcompete and eliminate the other.

2. Dominant and Keystone Species:

   • Dominant species: Are the most abundant or have the highest biomass and exert strong control over community structure.
   • Keystone species: Are not necessarily abundant but play a critical role in maintaining community structure through their ecological roles or niches. Their removal can lead to significant changes in the community.

3. Intermediate Disturbance Hypothesis: The hypothesis suggests that moderate levels of disturbance promote higher species diversity than low or high levels of disturbance. Moderate disturbance creates a mosaic of habitats, allowing for a greater variety of species to coexist.

4. Species Richness and Equatorial-Polar Gradient: Species richness tends to decline along an equatorial-polar gradient because of factors like climate stability, energy availability, and evolutionary history. Tropical regions near the equator generally have more stable climates, higher solar energy input, and longer evolutionary histories, supporting higher species richness.

5. Zoonotic Pathogens: Zoonotic pathogens are diseases transmitted from animals to humans. For example, Lyme disease, transmitted by ticks from deer and mice to humans, can be controlled by managing deer and rodent populations and implementing tick control measures.

Chapter 55

• Autotroph: An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun or from oxidation of inorganic substances to make organic molecules from inorganic ones.
• Biomass pyramid: A diagram representing the biomass in each trophic level of an ecosystem.
• Bioaugmentation: The use of organisms to add essential materials to a degraded ecosystem.
• Bioremediation: The use of organisms to detoxify and restore polluted ecosystems.
• Carnivore: An animal that mainly eats other animals.
• Decomposer: An organism that absorbs nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms and converts them to inorganic forms.
• Evapotranspiration: The evaporation of water from soil plus the transpiration of water from plants.
• Herbivore: An animal that mainly eats plants or algae.
• Heterotroph: An organism that obtains organic food molecules by eating other organisms or substances derived from them.
• Producer: An autotroph, which supports all other trophic levels.
• Primary consumer: An herbivore; an organism that eats plants or other autotrophs.
• Secondary consumer: A carnivore that eats herbivores.
• Tertiary consumer: A carnivore that eats other carnivores.
• Trophic efficiency: The percentage of production transferred from one trophic level to the next.

1. Energy Flow vs. Nutrient Cycling: Energy flows through an ecosystem in one direction, from producers to consumers, and is eventually lost as heat. Nutrients, however, cycle within an ecosystem, moving between biotic and abiotic components through processes like decomposition and nutrient uptake.

2. Factors Limiting Primary Production in Aquatic Ecosystems: Factors such as light availability and nutrient availability (especially nitrogen and phosphorus) can limit primary production in aquatic ecosystems. In some areas, iron can also be a limiting nutrient.

3. Biogeochemical Cycles:

   • Water Cycle: Involves evaporation, transpiration, condensation, precipitation, and flow through surface and groundwater.
   • Carbon Cycle: Involves photosynthesis, respiration, decomposition, and the exchange of carbon dioxide between the atmosphere and oceans.
   • Nitrogen Cycle: Involves nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.
   • Phosphorus Cycle: Involves the weathering of rocks, absorption by plants, consumption by animals, and decomposition. Unlike the other cycles, the phosphorus cycle does not have an atmospheric component.

Chapter 56

• Acid precipitation: Rain, snow, or fog with a pH less than 5.2.
• Biodiversity hotspot: A relatively small area with numerous endemic species and a large number of endangered and threatened species.
• Biological magnification: A process in which retained substances become more concentrated at each higher trophic level in a food chain.
• Chlorofluorocarbons: Chemical compounds used in aerosols, refrigerants, and other applications, that releases chlorine atoms into the atmosphere, resulting in ozone depletion.
• Conservation biology: A goal-oriented science that seeks to understand and counter the loss of biodiversity.
• Ecosystem services: Functions performed by ecosystems that directly or indirectly benefit humans.
• Effective population size: An estimate of the size of a population based on the numbers of females and males that successfully breed; generally smaller than the total population.
• Endangered species: A species that is in danger of extinction throughout all or a significant portion of its range.
• Extinction: The state or process of a species, family, or larger group being or becoming extinct.
• Extinction vortex: A downward population spiral in which inbreeding and genetic drift combine to cause a small population to shrink and, unless the spiral is reversed, become extinct.
• Greenhouse effect: The warming of Earth due to atmospheric accumulation of carbon dioxide and certain other gases, which absorb reflected infrared radiation and reradiate some of it back toward Earth.
• Introduced species: A species moved by humans, either intentionally or accidentally, from its native location to a new geographic region; also called an exotic species.
• Minimum viable population size: The smallest population size at which a species is able to sustain its numbers and survive.
• Movement corridor: A series of small clumps or a narrow strip of quality habitat (usable by organisms) that connects otherwise isolated patches of quality habitat.
• Ozone layer: The layer of ozone (O3) in the upper atmosphere that protects Earth from harmful ultraviolet radiation.
• Sustainable development: Development that meets the needs of people today without limiting the ability of future generations to meet their needs.
• Threatened species: A species that is considered likely to become endangered in the foreseeable future.
• Zoned reserve: An extensive region that includes areas relatively undisturbed by humans surrounded by areas that are used for economic gain and have been changed by human activity.

1. Levels of Biodiversity:

   • Genetic diversity: Genetic variation within a population and between populations. Example: different breeds of dogs.
   • Species diversity: The variety of species in an ecosystem or throughout the biosphere. Example: the number of different tree species in a forest.
   • Ecosystem diversity: The variety of ecosystems in the biosphere. Example: the different types of ecosystems in a region, such as forests, grasslands, and wetlands.

2. Major Threats to Biodiversity:

   • Habitat loss: Destruction and fragmentation of habitats. Example: deforestation for agriculture or urbanization.
   • Introduced species: Non-native species that outcompete native species. Example: the introduction of the Nile perch into Lake Victoria, which led to the extinction of many native fish species.
   • Overexploitation: Harvesting of wild populations at rates exceeding their ability to rebound. Example: overfishing of cod populations.
   • Global change: Alterations in climate, atmospheric composition, and ecological systems. Example: ocean acidification due to increased carbon dioxide levels.

3. Ecosystem Services: Functions performed by ecosystems that benefit humans, such as:

   • Pollination: Pollination of crops by insects.
   • Water purification: Filtration of pollutants by wetlands.
   • Climate regulation: Carbon sequestration by forests.

4. Biodiversity Hot Spots: Relatively small areas with many endemic species and a high number of endangered or threatened species. They are important because they contain a large proportion of Earth’s biodiversity and are in need of conservation efforts.

5. Zoned Reserves: Extensive regions with undisturbed areas surrounded by areas used for economic gain. Undisturbed areas provide resources to the surrounding developed land. Important as they promote sustainable economic activity as well as conservation.

6. Bioremediation and Biological Augmentation:

   • Bioremediation: Using organisms to detoxify polluted ecosystems. Example: using bacteria to clean up oil spills.
   • Biological augmentation: Using organisms to add essential materials to degraded ecosystems. Example: planting nitrogen-fixing plants to improve soil fertility.