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99 Cards in this Set
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- Back
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An ___ consists of a community of organisms in a physical environment |
Ecosystem |
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___ consists of populations of individual species, different kinds of plants, animals, fungi, bacteria, and so on |
Community |
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A ___ can be defined as all of the individuals of a species that inhabit a particular environment |
Population |
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The way that we define the environment determines the ___ |
Boundaries of the population |
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We often think of an environment as a limited area in which the individuals ___ |
Share the available resources |
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Anywhere ___ exist is, in a strict sense, ___ |
Organisms An ecosystem |
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Many of the most important organisms and ecological processes in all ecosystems are invisible to us because the ____ are small or because they and the processes occur in the ___ |
Organisms Soil |
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By observing the full range of interactions and processes in natural ecosystems we can ___ |
Learn how to manage crop ecosystems to achieve the goal of sustainability |
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___ is to minimize the inputs and maximize the contribution of ecosystem processes |
Sustainability |
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The organisms in an ecosystem interact according to ___ |
The nature of the species and their role in the ecosystem |
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Plants require ___ and many may require ___ |
Light, water, and nutrients for growth Pollinators and dispersal agents for reproduction |
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____ occurs when more than one organism draws on a resource that is in short supply |
Competition |
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A single ___ cannot utilize of the ___ or the whole of any one resource in the ___ |
Species Resources Environment |
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___ exist when a resource is partitioned so that different portions of it are accessible to only certain species |
Niches |
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For species to coexist in an ecosystem, they must ___ |
Occupy different niches |
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In healthy, natural ecosystems, every available niche tends to be filled, and consequently resources are fully exploited. It is difficult for new species to colonize the environment because it lacks open niches or unexploited resources and the result is called ____ |
Exclusion |
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___ have one or a few species that do not ___ |
Crop ecosystems Not exploit all of the resources of the environment |
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We call the other plants ___, and their presence is a problem to the extent that their ____ |
Weeds Resource requirements overlap those of the crop species |
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___ are consumed by a wide range of animals, which we call ___ |
Plants Herbivores |
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The ___ of herbivores emphasize the importance of ___ |
Diversity and large numbers Plants as a food source in terrestrial ecosystems |
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Crop ecosystems are usually more vulnerable to ____ because the number of ___ |
Herbivory Predators is low or nonexistent |
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It may be necessary to use ____, or other means to control slugs, insects, rodents, birds, or deer |
Chemicals, introduced predators and parasites |
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___ are organisms that derive their nutrition by ____, often producing symptoms of ___ such as swellings or discolored tissue |
Parasites Living in or on the tissue of another organism Disease |
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Plant parasites include many kinds of ___ |
Viruses, bacteria, and fungi |
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___ ___ is a parasite that can grow only in the host |
Obligate parasite |
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Parasites that can grow outside the plant are called ___ |
Facultative |
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All ____ are obligate parasites, whereas ___ may be obligate parasites or facultative |
Viruses Fungi and bacteria |
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Other classes of parasites include ___ and some ___, particularly those that form ___ |
Nematodes Insects and mites Galls on leaves and stems |
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Parasites differ from herbivores because ___ |
They cause a disease rather than simply eating their way through the tissue |
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___ is a microorganism that digest dead plant and animal material at or below the soil surface |
Saprophyte |
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___ are aided in their activity by ____ that break up large pieces of organic matter as they consume it |
Saprophytes Detritovores |
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Detritovores and saprophytes may be less important in crop ecosystems than in nature because ___ and ___ ___ are removed and the nutrients are replaced by ___ ____ |
Crops and crop residues Synthetic fertilizers |
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List the categories of organisms found in all terrestrial ecosystems: |
Primary producers (mainly plants) Herbivores Parasites Commensals Detritovores Saprophytes |
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___ are passed continuously from one organism to another along with the ___ that sustain the whole ecosystem and that ___ |
Nutrients Energy and carbon compounds Originally came from plants |
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___ is a collection of ecosystems with similar climate, soil, and plant composition |
Biome |
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___ is the main influence on the type of vegetation that develops |
Climate
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___ is a long term relationship between ___, in which the host does not usually die because this would also entail the death of the pathogen |
Parasitism A host and a pathogen |
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Although the host may not die, it is usually ___ |
Weakened making it vulnerable to attacks by other secondary organisms |
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___ are animals, often insects, that spend the juvenile phase of their life cycle in the tissues of another insect. When they emerge as adults the host is killed |
Parasitoids |
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Parasitoids can be helpful in crop ecosystems when they ___ |
Infect herbivorous insects such as caterpillars |
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___ is an obligate relationship between two organisms of different species living together in close association for their mutual benefit |
Symbiosis |
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___ plants are important for maintaining the nitrogen supply in natural ecosystems |
Nitrogen-fixing |
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The legume family includes many important crops such as ___ |
Beans, peas, and alfalfa |
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Rotating a nitrogen-fixing legume crop with a nonlegune on a regular basis is a common farming practice to ___ |
Keep nitrogen levels up in a field |
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A more general term for a mutually beneficial association between organisms is ___ |
Commensalism |
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The most important climatic variables are___ |
Temperature, rainfall (or more correctly, precipitation), any seasonal variation in both |
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___ are produced from parent material, such as rocks, by the interaction of climate and organisms |
Soils |
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___ are the key components of the ____ and influence ___ |
Plants Soil ecosystem All of the other organisms present |
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Temperature is primarily influenced by ___, and within latitudes, it is influenced by the ____ |
Latitude Height of the land above sea level |
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A key component in the relationship between climate and vegetation is ___ |
Soil |
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___ is a climbing or twining plant, usually woody |
Liane |
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Because of high rates of growth, ____ are rapidly taken up by plants and rapidly __ so rainforest soils contain little in the way of free nutrients |
Nutrients Recycled from dead organisms |
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After the Forest is cleared, ____ can be raised for a year or two, but the __ are soon ___ |
Good crops Nutrients Exhausted |
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In the desert, fertilizers must be used to ___ |
Compensate for the low fertility of the soils |
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A key component in the relationship between climate and vegetation is ___ |
Soil |
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___ is a climbing or twining plant, usually woody |
Liane |
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Because of high rates of growth, ____ are rapidly taken up by plants and rapidly __ so rainforest soils contain little in the way of free nutrients |
Nutrients Recycled from dead organisms |
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After the Forest is cleared, ____ can be raised for a year or two, but the __ are soon ___ |
Good crops Nutrients Exhausted |
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In the desert, fertilizers must be used to ___ |
Compensate for the low fertility of the soils |
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When the desert is irrigated, the ___ are left behind after the water ___ from the soil or through ___ |
Salts Evaporates Plant transpiration |
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Desert soils are difficult to manage in the long term because the ___ tend to accumulate to levels that ____ ___ ___ of plants |
Salts Inhibit the growth |
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___ are small flowering plants that grow in deciduous forests that start and complete their annual lifecycle in a very short time in the spring before trees leaf out |
Spring ephemerals |
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The ____ is composed of the plants that grow under the canopy of other taller plants |
Understory |
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The annual leaf fall adds a certain amount of nutrients to the litter layer of the ___ |
Temperate deciduous forest |
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The leaves contain on a fraction of the ___, and trees manage to withdraw much of the ___ from their leaves before they are shed. So forest soils ___ and tend to have only ___ |
Nutrients locked up in the permanent structure of the tree Nitrogen and phosphorous Develop slowly A thin organic-rich layer |
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What is the largest biome? |
Desert |
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A |
Taiga |
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____ are valuable crop for lumbar and paper making, but there is little prospect fro large scale production of other kinds of crops in this area. |
Coniferous trees |
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In the ___, the ground is permanently frozen except for a surface layer throughout the year |
Tundra |
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The short melt period in the summer allows only a low vegetation of ___ |
Dwarf shrubs, sedges, and grasses to develop |
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What is this describing? In terms of the vegetation that existed before human interference, which began several 1,000 years ago to change the vegetation to provide food directly for humans/animals that could be eaten by humans |
Biomes |
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Why have grasslands been the most extensively modified biome? |
Because of their value for agriculture |
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All the kinds of ecosystems that made up the biomes contained ____ or ___ which were often the most ___ ___ because ___ was permanently available |
Wet areas or wetlands Productive Water |
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___ are atmospheric environmental conditions in the immediate vicinity of the plant, including interchanges of energy, gases and water between atmosphere and soil |
Microclimates |
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A ___ is determined by hills and valleys or even small depressions in a field, proximity to large and small bodies of water, presence of large land masses or buildings |
Microclimates |
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The area between the deserts and the forests consists of ___ |
Grasslands and Savannas |
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The indication of how much we can expect to harvest from then without causing loss of species or collapse of the whole ecosystem is __ |
The productivity of ecosystems |
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The world’s terrestrial ecosystems can be divided into three broad groups of ___ |
High, intermediate, and low photosynthetic productivity |
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___ is the percentage of a plants biomass that is incorporated into the harvestable part |
Harvest index |
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The change in plant communities over time is know as ___ |
Succession |
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Succession begins with ___ that can survive under special conditions |
Pioneer species |
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___ is the theoretical end point of succession |
Climax community |
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Without cultivation ___ would move in, followed by a thicket of ___, and the process would culminate in a ___ |
Weeds Woody plants Forest of the longer-lived tree species |
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The further from the climax community we try to stay, the more ___ and ___ are required to maintain the ___ |
Work Inputs Ecosystem |
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___ is an estimate of the land area required by an individual, a geographic area, a sociopolitical group, or the whole population taken as a whole |
Human footprint |
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We can reduce our human footprint by reducing ___ |
The area of the intensity of our activities |
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___ is grassland and savanna is limited to some extent by ___, but ____ and ____ ____ are also important in maintaining these ecosystems |
Tree growth Lack of water Fire and grazing animals |
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Much of our footprint is related to ___ |
Energy use |
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Most of our energy consumption is based on ___, and a footprint is associated with ___ |
Fossil fuels Extraction, processing, and distribution of these fuels |
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A far greater footprint arises from the ___ produced as the fuel is burned to generate ___ |
Carbon dioxide Energy |
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Agriculture accounts for only about ___ of US energy use, so it can make only a ___ contribution to ___ ___ |
2% Minor Energy conservation |
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Most of the energy used for our food supply is ____ (for transportation processing, and storage) after ___ leaves the farm |
Consumed Produce |
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When fires sweep though grassland, ____, but grasses and herbaceous perennials, which have their ___ ___ at or below the ____ ___, typically survive |
Most trees are killed Growing points Soil surface |
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What type of plants accumulate nutrients in the roots and stems that are renewed from year to year? |
Grassland plants |
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____ contains reserves of nutrients and makes up a large part of the ___ that are characteristics of ___ around the world |
Organic matter Black earths Moist grasslands |
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How can arid lands be turned into desert? |
Overgrazing |
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___ can be devastating consequences of attempted cultivation |
Soil erosion |
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___ makes up the dominant vegetation in this boreal forest, or ___ and plant diversity is much ____ than in the ___ and ___ ___ |
Coniferous trees Taiga Lower Temperature Tropical forests |
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Because the conifers are mostly ___-___ ____, recycling and the availability of nutrients is ___ than in the ___ ___ |
Slow-growing evergreens Lower Deciduous forest |
