Ecology Unit Study Guide – Flashcards
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ecology
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the scientific study of interactions of organisms with their environments;from hydrothermal vents to solar-powered terrestrial systems
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organism
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a living thing that has (or can develop) the ability to act or function independently
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population
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a group of individuals of the the same species living in a particular geographic area
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community
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consists of all the populations of direct species that inhabit a particular area
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ecosystem
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includes all forms of life in a certain area and all the nonliving factors as well
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abiotic components
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includes temperature, forms of energy, water, inorganic nutrients, and other chemicals
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biotic components
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the organisms making up the community
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biosphere
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the global ecosystem- the sum of all the planet's ecosystems
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habitats
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specific environments in which organisms live
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tropics
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the region between latitudes 23.5 degrees north (the tropic of Cancer) and 23,5 degrees south (the tropic of Capricorn) that experiences the greatest annual input and least seasonal variation in solar radiation
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doldrums
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an area of calm or of very light winds that are created when moist air at the equator rises
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trade winds
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dominate the tropics
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temperate zones
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the latitudes between the tropics and the Arctic Circle in the north and the Antarctic Circle in the south
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prevailing winds
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major global air movements
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westerlies
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winds that blow form west to east
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ocean currents
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river like flow patterns in the oceans
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biomes
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the world's ecosystems, such as major ones like rain forests and deserts
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intertidal zone
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the area of shore where land meets ocean
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pelagic zone
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the open ocean itself
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phytoplankton
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microscopic algae and cyanobacteria that drift passively in the pelagic zone
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zooplankton
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small, drifting animals that usually have morphological features that keep them afloat
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benthic zone
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the seafloor
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photic zone
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a relatively small portion of ocean water and bottom into which light penetrates and in which photosynthesis occurs
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aphotic zone
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a vest, dark region underlying the photic zone
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continental shelves
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the submerged parts of continents
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coral reefs
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a visually spectacular and biologically diverse ecosystem that are found in warm tropical waters above the continental shelf
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estuary
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an area where a freshwater stream or river merges with the ocean
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wetland
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an area that is transitional between an aquatic ecosystem and a terrestrial one
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tropical forests
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occur in equatorial areas where the temperature is warm and days are 11-12 hours long year-round
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savanna
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a biome dominated by grasses and scattered trees
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deserts
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the driest of all terrestrial biomes, characterized by low and unpredictable rainfall (less that 30 cm a year)
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desertifacation
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the conversion of semiarid regions to desert an dis a significant environmental problem
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chaparral
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(the Spanish word for "place of evergreen scrub oaks") a region of dense, spiny shrubs with tough, evergreen leaves
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temperate grasslands
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have some of the characteristics of tropical savannas, but they are mostly treeless, except along rivers or streams, and are found in regions of relatively cold winter teperatures
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temperate broadleaf forests
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grow throughout midlatitude regions, where there is sufficient moisture to support the growth of large trees
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What are some examples of abiotic factors?
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temperature, forms of energy, water, inorganic nutrients, and other chemicals
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What are some examples of biotic factors?
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the organisms making up the community
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What are 4 influences of life in the biosphere?
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a) solar energy b) water c) temperature d) wind
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What are the organization levels of biology?
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1) organism 2) population 3) community 4) ecosystem 5) biome 6) biosphere
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What impact did DDT have on environmentalism?
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1) increases in farm productivity enabled developed nations such as the United States to grow surplus food and market it overseas 2) the worldwide incidence of malaria and several other insect-borne diseases was markedly reduced 3) threatened the survival of predatory birds and was showing up in human's milk 4) arise to genetic resistance to pesticides, evolving in an increasing number of pest populations, 1) increases in farm productivity enabled developed nations such as the United States to grow surplus food and market it overseas 2) the worldwide incidence of malaria and several other insect-borne diseases was markedly reduced 3) threatened the survival of predatory birds and was showing up in human's milk 4) arise to genetic resistance to pesticides, evolving in an increasing number of pest populations
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What is the sun's impact on creating climate zones?
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Uneven heating of the Earth causes winds and rains Low angle of incoming sunlight is cooler and has less rain Sunlight strikes Earth most directly = hotter & more rain
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How does physical landmarks contribute to climate?
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Air temperature declines by about 6 degrees Celsius with every 1,000 meters increase in elevation
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population density
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the number of individuals of a species per unit area or volume
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dispersion pattern
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refers to the way individuals are spaced within their area
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clumped
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individuals are aggregated in patches, and is the most common in nature
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uniform
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an even pattern of dispersion that often results from interactions between the individuals of a population
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random
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individuals in a population are spaced in a patternless, unpredictable way
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life tables
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determines how long, on average, an individual of a given age could be expected to live
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survivorship curves
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plot the proportion of individuals alive at each age
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intrinsic rate of increase
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the maximum capacity of members of that population to reproduce
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exponential growth model
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gives an idealized picture of unregulated population growth
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limiting factors
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environmental factors that restrict population growth
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logistic growth model
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a description of idealized population growth that is showed by limiting factors as the population size increases
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carrying capacity
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the maximum population size that a particular environment can support ("carry")
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density-dependent rates
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declining birth rates and rising death rates in response to increasing population density
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life history
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the series of events from birth through reproduction to death
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r-selection
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selection for life history traits that maximize reproductive success in uncrowded, unpredictable enviroments
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k-selection
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...
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CHAPTER 37 What is a biological community?
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An assemblage of all the populations of organisms living close enough to each other for potential interaction
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What are the key characteristics of a community?
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Species diversity, dominant species, response to disturbances, and trophic structure
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What is the species diversity of a community?(biodiversity)
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The variety of different kinds of organisms that make it up-has two components (the variations of lifeforms within the ecosystem)
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What is species richness?
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The total number of different species in the community
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In terrestrial situations, what is the dominant species?
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The most prevalent form of vegetation
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What are some examples of disturbances?
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Storms, fire, drought, floods, or human disruptions
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What is the trophic structure?
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The feeding relationships among the various species making up the community
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What does a community's trophic structure determine?
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The passage of energy and nutrients from plants and other photosynthetic organisms to herbivores and then to carnivores
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What are four types of interspecific interactions?
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Competition, predation, herbivory, and symbiosis
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What is interspecific interaction?
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If two different species are competing for the same resource, the growth of one or both populations may be inhibited
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What is the competitive exclusion principle?
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Two species so similar that they compete for the same limiting resources cannot coexist in the same place. Once will use the resources more efficiently and thus reproduce more rapidly than the other. Even a slight reproductive advantage will eventually lead to local elimination of the inferior competitior
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What is a niche?
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A species role in its community, or the sum total of its use of the biotic and abiotic resources in its habitat
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What are two possible outcomes of competition between species having identical niches?
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1) Either the less competitive species will be driven to local extinction 2) One of the species may evolve through natural selection to use a different set of resources
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What is resource partitioning?
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The differentiation of niches that enables similar species to coexist in a community
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What is predation?
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An interaction between species in which one species, the predator, kills and eats the other, the prey
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What is a very common type of defense against predation?
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Camoflague
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What other animal defenses are there?
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A porcupines's sharp quills The hard shells of clams and oysters Chemical defenses (Brightly colored)
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What is Batesian mimicry?
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A palatable or harmless species mimics an unpalatable or harmful model
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What is Mullerian mimicry?
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Two unpalatable species that inhabit the same community mimic each other
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What are keystone species?
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A species that exerts strong control on community structure because of its ecological role, or niche
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What are herbivores?
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Animals that eat plants or algae
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How do herbivorous insects locate food?
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By using chemical sensors on their feet, and their mouthparts are adapted for shredding tough vegetation or sucking plant juices
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What is coevolution?
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A series of reciprical evolutionary adaptations in two species
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When does coevolution occur?
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When a change in one species acts as a new selective force on another species, and counteradaptation of the second species in turn affects the selection of induviduals in the first species
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What does natural selection favor most?
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The parasites that are best able to find and feed on hosts
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What are pathogens?
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Disease-causing bacteria, viruses, or protists that could be thought of as microscopic parasites
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What is commensalism?
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One partner benefits without significantly affecting the other
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What is mutualism?
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Benefits both partners in the relationship
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What is ecological succession?
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The disturbed area may be colonized by a variety of species, which are gradually replaced by a succession of other species
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What is primary succession?
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When ecological succession begins in a virtually lifeless area with no soil
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What is secondary succession?
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Occurs where a disturbance has destroyed an existing community but left the soil intact
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What is a food chain?
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The sequence of food transfer up the trophic levels
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What are producers?
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The trophic level that supports all others consists of autotrophs
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What are primary consumers?
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Herbivores that eats plants, algae, or phytoplankton
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What are secondary consumers?
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Include many small mammals, such as the mouse, and a great variety of small birds, frogs, and spiders, as well as lions and other large carnivores that eat grazers
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What are tertiary consumers?
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Higher trophic levels that include snakes that eat mice and other secondary consumers
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What are quarternary consumers?
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these include hawks in terrestrial ecosystems and killer whales in the marine environment
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What are detritivores?
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Also known as decomposers
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What are decomposers?
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Derive their energy from detritus
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What are detritus?
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The dead material produced at all the trophic levels
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What are the community's main detritivores?
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The prokaryotes and fungi, which secrete enzymes that digest organic material and then absorb the breakdown products
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What is decomposition?
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The breakdown of organic materials to inorganic ones
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What is a food web?
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A network of intercoming food chains
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What does an ecosystem consists of?
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All the organisms in a community as well as the abiotic environment with which the organisms interact
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What is the energy flow?
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The passage of energy through the components of the ecosystem
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What is chemical cycling?
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Involves the transfer of materials within the ecosystem
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What is the biomass?
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The amount, or mass, of living organic material in an ecosystem
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What is primary production?
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The amount of solar energy converted to chemical energy (organic compounds) by an ecosystem's producers for a given area and during a given time period
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What does a pyramid of production show?
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Illustrates the cumulative loss of energy with each transfer in a food chain
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What supplies ecosystems with a continual influx of energy?
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The sun (in some cases Earth's interior)
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What are biogeochemical cycles?
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Chemical cycles in an ecosystem that involve both biotic and abiotic components
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What is an abiotic reservoir?
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Where a chemical accumulates or is stockpiled outside of living organisms
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What are the steps to a biogeochemical cycle?
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1) Producers incorporate chemicals from the abiotic reservoir into organic compounds 2) Consumers feed on the producers, incorporating some of the chemicals unto their own bodies 3) Both producers and consumers release some chemicals back to the environment in waste products (CO2 and nitrogen wastes of animals) 4) Detritivores play a central role; As organisms die, these decomposers return chemicals in organic form to the soil, water, and air; The producers gain a renewed supply of raw materials, and the cycle continues
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Why is water essential to life?
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organisms are made mostly of water and because water's unique properties make environments on Earth habitable
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What processes continuously move water between the land, oceans, and the atmosphere?
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Precipitation, evaporation, and transpiration from plants
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What is a major ingredient of all organic molecules?
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Carbon
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How much percent of the atmosphere is Nitrogen?
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80%
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Why is the amount of phosphates available to plants in natural ecosystems low?
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Weathering is generally a slow process
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What does the cycling of any chemical element in an ecosystem depend on?
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The web of feeding relationships between plants, animals, and detritivores and on geologic processes
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What does the Hubbard Brook experiment show?
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Major change in a terrestrial ecosystem
