47 terms

Biology 102 Final- Ch. 52, 55 and 56


Terms in this set (...)

nonliving factors, temperature, light, water, wind, nutrients, etc.
Affect of temperature on the distribution of organisms in biomes
effects biological processes, most organisms function best in temp range, temps outside range cause animals to expand energy regulating their internal temp
Affect of salinity on the distribution of organisms in biomes
affects water balance of organisms through osmosis, areas of high salinity typically have few animal or plant species
Affect of sunlight on the distribution of organisms in biomes
absorbed by photosynthetic organisms, provides energy that drives most ecosystems, competition for sunlight high underneath forests, too much light can limit the survival of organisms too- high temps, animals unable to cool themselves, UV damage
Affect of rocks and soil on the distribution of organisms in biomes
pH mineral composition and physical structures of rocks limit distribution of plants and thus animals that feed on them contributing to the patchiness of terrestrial ecosystems
Affect of water and oxygen on the distribution of organisms in biomes
dramatic variation in water availability among habitats, water affects oxygen availability in water aquatic environments and flooded soils
living factors, the other organisms apart of an individual's environment
-Ex: predation and herbivory, presence or absence of pollinators, food resources, parasites, pathogens and competing organisms can act as a limitation on species distribution
How might a body of water affect regional climatic conditions
-Ocean currents affect coastal climates by heating/cooling overlaying air masses that pass over land
-Water has a high specific heat→ moderates climate of nearby land
-On hot days when land is hot, air rises and draws cool air in from water. Contrastingly, at night when land is cooler, the air over water rises and moves toward land, drawing cooler air over water
How might a mountain range affect regional climatic conditions
-When warm, moist air approaches the windward side → air warms and cools, releasing moisture
-On leeward side, cooler, dry air descends, absorbing moisture and producing "rain shadow", many deserts
-Affect amount of sunlight reaching area→ temp and rainfall → influence species distribution locally
Photic zone
upper zone, sufficient light for photosynthesis, rooted and floating plants in littoral zone, phytoplankton, zooplanktonand fish in limnetic zone
Aphotic zone
lower zone, little light penetration, fish
Benthic zone
at the bottom of all aquatic zones, deep or shallow, sand and organic and inorganic sediments, occupied by communities of organisms called the benthos, invertebrates, seaweed, algae, most consumers depend entirely on detritus, worms, arthropods and echnoderms
Abyssael zone
deep in aphotic zone, 2,000-6,000 m below surface
Thermal stratification
light decreases with depth, creating stratification
-A narrow layer of abrubt temperature change in oceans and lakes
-Separates the more uniformly warm upper layer from the more uniformly cold deeper waters
Seasonal turnover
-Many temperate lakes undergo a semiannual mixing of their waters as a result of changing temperature profiles
-Sends oxygenated water from lake's surface to the bottom and brings nutrient-rich water from bottom in spring and autumn.
-These changes are essential for the survival and growth of organisms within all levels
Explain why the following statement is false: "All communities on Earth are based on primary producers that capture light energy by photosynthesis."
In some deep-sea, dark, hot environments where there is a hydrothermal vent, the food producers are chemoautotrophic prokaryotes. They obtain energy by oxidizing H2S formed by a reaction of the hot water with dissolved sulfate. Also occurs deep underground or in ice.
-Support all heterotrophs (primary producers)
-Photosynthetic organisms that use the light energy to synthesize sugars and other oganic compounds
-Depend directly or indirectly on the outputs of primary producers for their source of energy
-Consumers- herbivores and carnivores
-Detritovores and decomposers
Explain how decomposition connects all trophic levels in an ecosystem.
-They get their energy from detritus
-They convert organic matter from all trophic levels to inorganic compounds usable by primary producers
-Producers can then recycle these elements into organic compounds
-Make nutrients available to other organisms in the system
Explain how energy is said to flow and nutrients are said to cycle within ecosystems.
Nutrients are cycled through food chains, while energy is a one-way flow from the sun, processed through consumption and loses a significant percentage of energy as it goes up in trophic levels. You can "recapture" nutrients, but not energy.
Primary production
the amount of light energy converted to chemical energy-in the form of organic compounds- by autotrophs during a given time period in an ecosystem
Limiting factors of primary production
1.Light limitation: depth of light penetration affects pp throughout photic zone

2.Nutrient limitation:
-Limiting nutrient- the element that must be added for production to increase, most often nitrogen or phosphorus
-Concentrations of these are usually low in photic zone because they are rapidly taken up by phytoplankton and detritus sinks to bottom
-Iron also limiting nutrient
-Areas of upwelling, where deep nutrient-rich waters circulate to the ocean surface have high pp
-Lakes- common, eutrophication, phosphorus limits cyanobacteria growth
Water Cycle Reservoirs
-97% oceans
-2% glaciers/polar ice caps
-1% lakes/rivers/groundwater
Water Cycle processes
-Evaporation of liquid water by solar energy
-Condensation of water vapor into clouds
-Transpiration by plants moves water into atmosphere
-Surface and ground water flow return water to oceans
Carbon Cycle Reservoirs
-fossil fuels
-sediments of aquatic ecosystems
-plant and animal biomass
Carbon Cycle processes
-Photosynthesis by plants and phytoplankton removes it from atmosphere→ approximately equaled by CO2 added to atmosphere through cellular respiration
-Burning of fossil fuels and wood adds it to atmosphere
-Over geological time, volcanoes are also a source
Nitrogen Cycle Reservoirs
-sediments of lakes/rivers/oceans
-surface water and groundwater
-biomass of living organisms
Nitrogen Cycle processes
-Nitrogen fixation: conversion of N2 to forms that can be used by plants, fixed by certain bacteria
-Industrially produced fertilizers and legume crops- nitrogen input
-Denitrification: reduction of nitrate to nitrogen gases
-Human activities release large amounts of reactive nitrogen gases- nitrogen oxides
Phosphorus Cycle Reservoirs
-sedimentary rocks of marine origin
Phosphorus Cycle processes
-Weathering of rocks adds PO3- to soil, some leaches into groundwater and surface water
-Phosphate taken up by producers and incorporated into biological molecules may be eaten by consumers → phosphate returned to soil/water by decomposition of biomass or excretion by consumers
-Only small amounts move through atmosphere- dust and sea spray
Describe how agricultural practices can interfere with nitrogen cycling.
Farmers use nitrogen fertilizers in soils. This is affective in the short run but bad in the long term because of a nitrogen overload:
-Destroys the fertility of the soil
-Excess nitrogen leads to the loss of other soil nutrients.
-Nitrates are soluble in water → acidification of soil, rivers, lakes, etc → more acidic
How does agriculture and soil erosion on land lead to dead zones in the ocean?
-Harvests organic matter so that nutrients aren't returned to soil → creates need for fertilizers
-When soil is eroded or nitrogen fertilizers are used there is an increase in nitrate runoff into streams and rivers.
-Nitrogen overload in water promotes dense growth of phytoplankton, resulting in algae blooms
-Algae is short lived→ decomposition of algae consumes oxygen→ fish die
-"Dead zone" worse in summer
What is the source of acid rain and how does it affect the soil?
-Caused by a chemical reaction that begins with compounds like sulfur dioxide and nitrogen oxides (dissolve easily in water) released into air
-Substances rise high in atmosphere and mix with water, oxygen and other chemicals to form acidic pollutants (acid rain)
-Dissolves nutrients in soil (such as magnesium and calcium), which trees need to be healthy, and releases aluminum, which makes it difficult for trees to absorb water
-Changes the pH of soil and water, makes it more acidic
3 ways in which biodiversity is measured
-Genetic diversity
-Species diversity
-Ecosystem diversity
Genetic diversity
Comprises not only the individual genetic variation within a population, but also the genetic variation between populations that is often associated with adaptations to local conditions
-If one population becomes extinct, then a species may have lost some of the genetic diversity that makes microevolution possible
-This erosion of genetic diversity in turn reduces the adaptive potential of the species
Species diversity
the variety of species in an ecosystem or across the biosphere
-As more species are lost to extinction, species diversity decreases
-Endangered and threatened species
Ecosystem diversity
the variety of the biosphere's ecosystem
Threats to biodiversity
-Habitat loss
-Introduced species
-Global change
Habitat loss
-Human alteration of habitat is greatest threat- agriculture, urban development, forestry, mining and pollution
-Global climate change alters habitat
-Leads to species loss b/c smaller populations in habitat fragments have a higher probability of local extinction
-Threatens aquatic biodiversity too (coral reefs, rivers-dams, reservoirs)
Introduced species
-AKA Non-native/exotic species: species that humans move intentionally or accidently from the species' native locations to new geographic regions- ex: ship, airplane travel
-Free from predators, parasites and pathogens that limit their population in their native habitat →species may spread rapidly through new region
-Can disrupt new region by preying on native species, outcompeting native species for resources
-Some species introduced with good intentions but goes wrong
-Refers generally to the human harvesting of wild organisms at rates exceeding the ability of populations of those species to rebound
-Species with restricted habitats (e.g. small islands) are particularly vulnerable to this
-Large organisms with low reproductive rates are also at risk (e.g elephants- overhunting, whales)
Global change
-Includes alterations in climate, atmospheric chemistry, and broad ecological systems that reduce the capacity of earth to sustain life
Explain why toxic compounds usually have the greatest effect on top-level carnivores.
-Toxins are ingested by organisms and accumulate in the fatty tissues
-These toxins become more concentrated in successive trophic levels of a food wed- biological magnification
-Magnification occurs because the biomass at any given trophic level is produced from a much larger biomass ingested from the level below
-Thus, top-level carnivores tend to be the organisms most severely affected by toxic compounds
Describe the greenhouse effect and how increased atmospheric concentrations of carbon dioxide are changing Earth's heat retention.
-When light energy hits the earth, much of it is reflected off the surface→ CO2 causes the earth to retain some of the energy that would ordinarily escape the atmosphere → greenhouse effect
-CO2 warms the earth
Ozone depletion causes
-Accumulation of CFCs- chemicals uses in refrigeration, propellant in arosol cans and for manufacturing purposes
-The breakdown products from these chemicals rise to the stratosphere, where the chlorine they contain reacts with ozone to reduce it to O2
-Subsequent reactions free the chlorine, allowing it to react with other ozone molecules in a catalytic chain reaction
Ozone depletion consequences
-Increased levels of UV radiation that reaches surface of earth
-Increases in skin cancer, cataracts as well as unpredictable effects on crops and natural communities
-Chlorine molecules present today will continue to reduce ozone for at least a century