APES

Chapter 3

• Combination of all ecosystems on Earth form the Biosphere

  • 20-km thick layer around Earth between the deepest ocean bottom and the highest mountain peak

• When one organism consumes another, not all of the energy in the consumed organism is transferred to the consumer

• Photosynthesis is the process of using solar energy to convert carbon dioxide and water into glucose

  • Glucose is a form of potential energy that can be used by a wide range of organisms 

  • Also produces oxygen as a waste product 

  • Solar energy + 6 H2O + 6 CO2 → C6H12O6 + 6 O2

• Cellular respiration is the process by which cells unlock the energy of chemical compounds 

  • Aerobic respiration is when cells convert glucose and oxygen into energy, CO2, and water 

  • Anaerobic respiration is when cells convert glucose into energy in the absence of oxygen 

  • Does not provide as much energy as aerobic respiration

  • Energy + 6 H2O + 6CO2 ← C6H12O6 + 6 O2

• Producers both produce and consume oxygen 

  •  Generate more oxygen through photosynthesis than they consume through respiration 

  • Overall, producers photosynthesize more than they respire 

  • Net effect is excess of oxygen released into the air and an excess of carbon stored in the tissues of producers 

• Consumers are incapable of performing photosynthesis and must obtain energy by consuming other organisms 

  • Primary Consumers 

    • Herbivores

    • Include a variety of familiar plant and algae eating animals such as zebras, grasshoppers, tadpoles, and zooplankton

  • Secondary Consumers

    • Carnivores

    • Lions, hawks, rattlesnakes

  • Tertiary Consumers

    • Carnivores that eat secondary consumers

    • Bald eagles 

• Successive level of organisms consuming one another are knows as trophic levels

• Sequence of consumption from producers through tertiary consumers is the food chain 

  • Helps us visualize how energy and matter move between trophic levels 

• Food web is a complex model of how energy and matter move through trophic levels 

• Omnivores operate at several trophic levels 

  • Grizzly bears who eat berries and fish 

  • Venus Fly Trap can photosynthesize and digest insects 

• Each trophic level eventually produces dead individuals and waste products 

  • Scavengers

    • Organisms that consume dead animals such as vultures

  • Detritivores

    • Organism such as dung beetles that specialize in breaking down dead tissues and waste products into smaller particles

  • Decomposers

    • Fungi and bacteria that complete the breakdown process by converting organic matter into small elements and molecules that can be recycled back into the system 

• Amount of energy available in an ecosystem determines how much life the ecosystem can support 

• Gross Primary Productivity

  • Measure of the total amount of solar energy that the producers in the system capture via photosynthesis over a given time 

  • GPP does not subtract the energy that is lost when the the producers respire 

  • Measure of how much photosynthesis is occurring over some amount of time 

  • Difficult ot calculate because a plant rarely photosynthesizes and respires simultaneously 

• Net Primary Productivity 

  • Energy captured by producers in an ecosystem minus the energy producers respire 

  • Ranges from 25 to 50 percent of the GPP 

  • Helps measure change in a system 

• Net primary productivity of an ecosystem establishes the rate at which biomass- the total mass of all living matter ina  specific area- is produced over a given amount of time 

• The amount of biomass present in an ecosystem at a particular time is its standing crop 

  • Standing crop measures the amount of energy in a system at a given time, while productivity measures the rate of energy production over a span of time 

• Proportion of energy that can be passed from one trophic level to another is referred to as ecological efficiency 

  • Are fairly low: range from 5 to 20 percent 

  • Total biomass available at a given trophic level leads to only 10 percent being converted into energy at the next higher trophic level

• Trophic pyramid is representation of the distribution of biomass, numbers, of energy among trophic levels

  • Tend to have similar proportions across ecosystems 

  • Most of the energy and biomass are found at the procure level and they commonly decrease as we move up the pyramid

Chapter 6 

• Community ecology is the study of interactions among species

• Symbiotic relationships 

  • Relationship between two species that  are living in close association with each other 

  • Include competition, predation, parasitism, and herbivory

Negative interactions

• Competition

  • Struggle of individuals to obtain a shared limiting resource 

  • Competitive exclusion principle

    • Two species competing for the same limiting resource cannot coexist 

  • Leads to resource partitioning in which two species divide a resource based on differences in their behavior or morphology 

  • Temporal resource partitioning 

    • Process in which two species utilize the same resource but at different times 

  • Spacial resource partitioning

    • Two species reduce competition by using different habitats 

  • Morphological Resource partitioning

    • Evolution of differences in body size or shape 

• Predation 

  • Interaction in which one animal typically kills and consumes the other animal 

  • Parasitoids are animals that lay eggs inside other organisms

  • Defenses include behavioral, morphological, and chemical 

• Parasitism 

  • Interaction in which one organism lives on or is in another organism 

  • Single parasite rarely causes the death of its host 

  • Pathogens are parasites that cause diseases in their hosts 

• Herbivory

  • Interaction in which an animal consumes a producer 

  • Typically only eat a portion of a producer without killing it  

Positive Interactions

• Mutualism

  • Interaction between two species that increases the chances of survival or reproduction of both species 

  • Under such conditions, natural selection will favor individuals that no longer engage in the mutualistic interaction

• Commensalisms

  • Relationship between species in which one species benefits and the other species is neither harmed nor helped 

  • Very common in nature 

• Keystone species is a species that is not very abundant but has a large effect on an ecological community 

  • Beavers

  • Without the keystone in place, the arch would fall apart

• Ecosystem engineer is a keystone species that creates or maintains habitat for other species 

  • Beavers and alligators 

Chapter 4

• Terrestrial Biomes are geographic regions categorized by a particular combination of average annual temperature, annual precipitation, and distinctive plant growth forms on land

• Aquatic Biomes are aquatic regions characterized by a particular combination of salinity, depth, and water flow 

• Tundra Biome

  • Cold and treeless with low growing vegetation 

  • Growing season is usually about 4 months during the summer, when the polar region is titled toward the Sun and the days are very long

    • During this time, the upper layer of soil thaws, creating pools of standing water 

  • Permafrost is an impermeable, permanently frozen layer of soil

    • Prevents water from draining and roots from penetrating 

  • Permafrost and cold temperatures prevent deep rooted plants from growing 

  • Little precipitation, but enough to support plant growth 

  • Contains small woody shrubs, mosses, heaths, lichens

  • Dead plants and animals decompose very slowly 

• Boreal forest Biome

  • Forest biome made up primarily of coniferous evergreen trees that can tolerate cold winters and short growing seasons

  • Sometimes called Taiga 

  • Has a very cold climate and plant growth is more constrained by temperature than by precipitation 

  • Soil is covered in a thick layer of organic material, but poor in nutrients 

  • Some deciduous trees such as birch, maple, and aspen can be found 

  • Needles of coniferous trees can tolerate freezing conditions

  • Serve as an important source for paper,pulp, and building materials 

• Temperate Rainforest Biome 

  • Coastal biome typified by moderate temperatures and high precipitation

  • Winters are rainy and summers are foggy

  • Supports growth of very large trees

  • Slow decomposition, but not as slow as the tundra or Boreal forest

• Temperate Seasonal Forest

  • Biome with warm summers and cold winters with over 1 m of precipitation annually 

  • Dominated by deciduous trees

  • Rapid decomposition 

  • Have high soil fertility and support plant productivity 

  • Said to be one of the first biomes to be converted to agriculture on a large scale 

• Woodland/Shrubland Biome 

  • Biome characterized by hot, dry summers and mild, rainy winters

  • 12 month growing season, but plant growth is constrained by high temperatures and low precipitation in the summer and by cool temperatures and high precipitation in the winter

  • Ideal conditions for growing grapes to make wine 

  • Favor occurrence of wildfires 

  • Drought resistant shrubs such as Yucca, scrub, oak, and sagebrush 

  • Soil is low in nutrients due to leaching by the winter rains 

  • Also called chaparral 

• Temperate Grassland/Cold Desert

  • Biome characterized by cold, harsh winters, and hot, dry summers

  • Plant growth is similar to Woodland 

  • Fires are common, as the dry and frequently windy conditions fan flames ignited by lightning 

  • Cold deserts have even sparser vegetation than shortgrass prairies

  • Very cold winters and do not support characteristic plan growth of hot deserts such as cacti and euphorbs 

• Tropical Rainforest

  • Warm and wet biome found between 20 degrees N and 20 degrees S of the equator, with little seasonal temperature variation and high precipitation 

  • High productivity and rapid decomposition 

  • High rate of decomposition causes the soils to lose their fertility quickly , so little undecomposed organic matter(humus)

  • Contain mot biodiversitY 

  • Main threat is deforestation 

• Tropical Seasonal Forest/ Savanna

  • Biome marked by warm temperatures and distinct wet and dry seasons

  • Tropical deciduous forest

  • Common plants include acacia and baobab trees

  • Grazing and fire discourage growth of many smaller woody plants and keep the savanna landscape open 

  • Presence of trees and warmer average annual temperature differentiate savanna from grassland 

  • Promotes decomposition, but low precipitation constrains plants from using soil nutrients that are released

  • Soils are fertile 

• Subtropical Desert

  • Biome prevailing at approximately 30 degrees N and S with hot temperatures, extremely dry conditions, and sparse vegetation 

  • Also known as hot deserts

  • Contains Cacti, Euphorbs, and succulent plants

  • When there is rainfall, growth is rapid 

• Aquatic Biomes are not categorized by temperature 

• Freshwater Biomes include streams, rivers, lakes and wetlands

• Saltwater Biomes include shallow marine areas such as estuaries and coral reefs, also the ocean

• Streams and Rivers

  • Characterized by flowing fresh water that may originate from underground springs or as runoff from rain or melting snow

  • Streams are typically narrow and carry relatively small amounts of water

  • Rivers are typically wider and carry larger amounts of water 

  • Fast moving streams and rivers typically have stretches of turbulent water called rapids, where water and air are mixed together

  • The mixing allows large amounts of oxygen to enter the water and supports fish fish species

  • Slower moving rivers experience less mixing of air and water which favor species that can handle low-oxygen conditions

    • Catfish

• Lakes and Ponds

  • Contain standing water, at least some of which is too deep to support emergent vegetation 

  • Lakes are larger than ponds

  • Littoral zone is the shallow zone of soil and water in lakes and ponds where most algae and emergent plants grow

    • Most photosynthesis occurs in this zone

  • Limnetic zone is a zone of open water in lakes and ponds

    • Contains phytoplankton 

    • Extends as deep as sunlight penetrates

  • Profundal zone is region of water where sunlight does nor each, below the limnetic zone in very deep lakes 

    • Producers cannot survive here

  • Benthic zone is the muddy bottom of a lake,pond, or ocean 

  • Lakes are classified by their level of primary productivity 

    • Low productivity due to low amounts of nutrients such as phosphorous and nitrogen in the water are called oligotrophic 

    • Moderate level of productivity is mesotrophic

    • High level of productivity is Eutrophic 

• Freshwater Wetlands

  • Aquatic biomes that are submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation 

  • Support species of plants that are specialized to live in submerged or saturated oils

  • Include swamps, marshes, and bogs

  • Swamps are wetlands that contain emergent tres

  • Marshes are wetlands that contain primarily non woody vegetation

  • Bogs are very acidic

  • Wetlands can take in large amounts of rainwater and release it slowly into the groundwater or into nearby streams

• Marine biomes contain salt water and can be categorized as salt marshes, mangrove swamps, intertidal zones, coral reefs and the open ocean. 

• Salt Marshes

  • Marsh containing nonwoody emergent vegetation, found along the coast in temperate climates

  • Found within an estuary which is an area along the coast where the fresh water of a river mixes with salt water from the ocean

  •  Habitat for spawning fish and shellfish 

• Mangrove swamps

  • Swamp that occurs along tropical and subtropical coasts, and contains salt-tolerant trees with roots submerged in water

  • Mangrove trees are salt tolerant 

• Intertidal Zones

  • Narrow band of coastline between the levels of high tide and low tide

  • Range from steep rocky areas to broad sloping mudflats 

• Coral Reefs

  • Most diverse marine biome on Earth, found in warm, shallow waters beyond the shoreline

  • Corals are tiny animals that secrete a layer of limestone to form an external skeleton 

  • Corals live in water that is relatively poor in nutrients and food 

  • Corals die and their skeletons accumulate to become a coral reef 

  • Coral Bleaching is a phenomenon in which algae inside corals die, causing to turn white

• Open Ocean

  • Deep ocean water, located away from the shoreline where sunlight can no longer reach the ocean bottom

  • Photic zone is the upper layer of the ocean water in the ocean that receives enough sunlight fir photosynthesis 

  • Chemosynthesis is process used by some bacteria in the ocean to generate energy with methane and hydrogen sulfide

• Biogeochemical Cycle

  • Movements of matter within and between ecosystems 

  • Components that contain matter(air, water, and organisms) are referred to as pools

  • Processes that move matter between pools are knows as flows

• The movement of water through the biosphere is known as the Hydrologic cycle

  • The release of water from leaves during photosynthesis is transpiration

  • Combined amount of evaporation and transpiration is called evapotranspiration

  • Helps move elements that are dissolved in the water

• Harvesting trees can reduce evapotranspiration

  • Runoff and percolation can increase

  • Leads to erosion and flooding

• Carbon makes up 20% of an organisms body weight68

• Carbon Cycle

  • Movement of carbon around the biosphere

  • Photosynthesis, respiration, exchange, sedimentation, burial, extinction and combustion

  • The amount of carbon released from the ocean into the atmosphere roughly equals the amount of atmospheric CO2 that diffuses into ocean water

  • Portion of Carbon dioxide dissolved into the ocean combined with calcium ions to form calcium carbonate

    • Compound which can precipitate out of the water and form limestone and dolomite rock via sedimentation and burial 

  • Although sedimentation is a long process, small amounts of calcium carbonate sediment formed each year have accumulated over millions of years to form the largest carbon pool in the slow part of the carbon cycle 

  • Extraction is a relatively recent phenomenon 

  • Extraction AND combustion alter the Carbon Cycle

  • Combustion, Respiration, and Decomposition all cause organic molecules to be broken down to produce CO2, water, and energy 

    • However, respiration and decomposition are biotic processes, whereas combustion is an abiotic process

  • Exchange of carbon between the Earth’s surface and atmosphere is in a steady state

  • Excess CO2 in the atmosphere acts to increase the retention of heat energy in the biosphere

    • Results are global warming 

• Nitrogen Cycle

  • Macronutrients

    • Six key elements needed by organisms in a relatively large amount

      • Nitrogen, phosphorous, calcium, magnesium, and sulfur

  • Nitrogen is considered a limiting nutrient for producers

    • Nutrient required for the growth of an organism but available in a lower quantity than other nutrients 

  • Nitrogen Cycle is the movement of nitrogen around the biosphere

  • Includes: Nitrogen Fixation, Nitrification, Assimilation, Mineralization, and denitrification 

  • Nitrogen Fixation

    • Process that converts nitrogen gas in the atmosphere(N2) into forms of nitrogen that producers can use

    • Can office through biotic or abiotic processes

    • Biotic Fixation

      • Cyanobacteria can convert N2 gas into ammonia (NH3), which is rapidly converted to ammonium (NH4+), a form that producers can use 

    • Abiotic fixation

      • N2 can be fixed in the atmosphere by combustion processes, which then convert N2 into Nitrate(NO3-)

      • Nitrate is carried to Earth’s surface via precipitation 

  • Nitrification

    • Conversion of ammonium into nitrite, then into nitrate 

    • Conducted by specialized species of bacteria

    • Nitrite is not used by most producers, but nitrate is

  • Assimilation

    • Process by which producers incorporate elements into their tissues

    • Usually when primary consumers feed on producers, producers nitrogen is assimilated into the tissue of the consumers, while rest is eliminated as waste products

  • Mineralization

    • Process by which fungal and bacterial decomposers break down the organic matter found in dead bodies and waste products and convert it into inorganic compounds 

    • Sometimes called ammonification

      • Process by which fungal and bacterial decomposers break down the organic nitrogen found in dead bodes and waste products and convert it into inorganic ammonium 

  • Denitrification

    • Final step which involves the conversion of nitrate in a series of steps into the gases nitrous oxide(n2o),and eventually, nitrogen has which is emitted into the atmosphere 

    • Conducted by bacteria that live under anaerobic conditions 

• The Phosphorus Cycle

  • Movement of phosphorous in the biosphere

  • Primarily operates between land and water; There is no gas phase 

  • Phosphorous rarely changes form: Typically found in the form Phosphate 

  • Producers on land and in the water take up inorganic phosphate and assimilate the phosphorous into their tissues as organic phosphorous 

  • Abiotic process involves movement between water and land 

    • Phosphorous is not soluble in water, so much of it precipitates out of solution in the form of phosphate-laden sediments

    • Over time, geologic forces can lift these ocean layers and they become mountains

    • The phosphate rocks in the mountain are slowly weathered, brining the phosphorous to terrestrial habitats

  • Limiting nutrient in aquatic habitats 

  • Increased phosphate in aquatic ecosystems can cause algal blooms 

    • Water will become hypoxic: lox in oxygen

  • Dead zone os when oxygen concentrations become so low that it kills other aquatic animals 

• The Sulfur Cycle

  • Producers absorb sulfur through their roots in the form of sulfate ions

  • Volcanic eruptions are natural source of atmospheric sulfur int he form of sulfur dioxide 

  • SO2(atmospheric sulfur) turns into sulfuric acid when it mixes with water

  • Carried back to earth when it rains or snow