BIOL 101 Unit #5 Chapter 20

what is an ecosystem?

a community of living organisms & their interactions with their abiotic environment

- tide pools (small ecosystem), tropical rainforests (large ecosystem)

what are the three categories of ecosystems?

freshwater, marine, and terrestrial

what influences community dynamics?

a habitat's climate, elevation, and geology

what is a biome?

a large-scale community of organisms, primarily defined on land by dominant plant types that exist in geographic regions of the planet with similar climatic conditions

- how terrestrial ecosystems are grouped (tropical rainforests, deserts, grasslands, tundras)

what is the equilibrium? (ch.20 def.)

the steady state of a system in which the relationships between elements of the system do not change

how are ecosystems measured?

resistance and resilience

what is resistance (ecological)?

the ability of an ecosystem to remain at equilibrium in spite of disturbances

what is resilience (ecological)?

the speed at which an ecosystem recovers equilibrium in spite of disturbances

what is the food chain?

linear sequence of trophic (feeding) relationships among producers, primary consumers, and higher level consumers in an ecosystem

what are primary consumers?

mainly herbivores that consume producers (plants); obtaining the producers energy

what are secondary consumers?

usually carnivores that eat the primary consumers

what are tertiary consumers?

carnivores that eat secondary consumers/other carnivores

what are apex consumers?

organism at the very top of a food chain

what is a food web?

web of trophic (feeding) relationships among producers, primary consumers, and higher level consumers in an ecosystem

what is a grazing food web?

food web that has plants or other photosynthetic organisms at its base, followed by herbivores and various carnivores

what are detrital food webs?

food web supported by dead or decaying organisms rather than by living autotrophs

how do living things acquire energy?

- autotrophs harness light/chemical energy

- heterotrophs acquire energy through the consumption and digestion of other living or previously living organisms

what are autotrophs?

organism capable of synthesizing its own food molecules from smaller inorganic molecules

- most critical for ecosystems being the producer

what are photoautotrophs?

organism that uses sunlight as an energy source to synthesize its own food molecules

- plants, algae, photosynthetic bacteria

what are chemoautotrophs?

an organism capable of synthesizing its own food using energy from inorganic molecules

- bacteria & archaea found in rare ecosystem; sunlight not available (the deep bottom of the sea)

what is gross primary productivity?

rate at which photosynthetic producers incorporate energy from the sun

what is net primary productivity?

energy that remains in the producers after accounting for the organisms respiration and heat loss

- net productivity available to primary consumers (who consume the producers)

what is biomagnification?

increasing concentration of persistent, toxic substances in organisms at each trophic level, from the producers to the apex consumers

- pesticide DDT, coolant PCB, fish consumes it and transfer it to the next trophic level (constantly increasing)

what are biotic & abiotic components of an ecosystem?

Abiotic: water, air, soil, climate

Biotic: all living things

who are ecosystem biologists?

scientists who study how nutrients & energy are stored and moved among organisms and the environment

what is biomagnification (EXTRA vid. notes)?

a fat soluble pollutant stored in an organisms fat

- (ex.) DDT dissolves in an organisms fat, can't get removed

what is the biogeochemical cycle?

the recycling of minerals and nutrients through the biotic and abiotic world

what is the hydrosphere?

the region of the planet where water exists, including liquid water on the surface (rivers, lakes, oceans), beneath the surface (groundwater), or ice (polar ice caps), and water vapor in the atmosphere

what are non-renewable resources?

a resource, such as a fossil fuel, that is either regenerated very slowly or not at all

what is subduction?

the movement of one tectonic plate beneath another

- how carbon sediments from ocean floor are taken deep within the Earth

what is eutrophication?

process whereby nutrient runoff causes the excess growth of microorganisms and plants in aquatic systems

- artificial fertilizer on plants washed off (runoff) into the ocean

what are dead zones?

an area in a lake and ocean near the mouths of rivers where large areas are depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping toxic chemicals, and other human activities

- part of the phosphorus cycle

what is fallout?

the direct deposition of solid minerals on land or in the ocean from the atmosphere

what is acid rain?

corrosive rain caused by ran water mixing with sulfur dioxide gas as it falls through the atmosphere, turning it into weak sulfuric acid, causing damage to aquatic ecosystems

what are the major biogeochemical cycles?

water, carbon, nitrogen, phosphorus, and sulfur cycles

how does energy function in biogeochemical cycles?

it enters as sunlight, leaves as heat

how does matter function in biogeochemical cycles?

it is recycled, present in all of the cycles

how does the water cycle process work?

driven by the sun's energy, evaporation, and sublimation (solids to gas; skips liquid), condensation & precipitation, subsurface water flow, surface runoff and snowmelt

how does the carbon cycle process work?

rapid carbon exchange (living organisms), fossilized carbon (non-renewable) increases carbon dioxide levels

process of nitrogen cycle?

occurs in terrestrial systems, ammonification (waste product from an organism) into bacteria

- nitrification: ammonia to nitrites to nitrates

- denitrification: nitrates to nitrogen gas

what are the bacteria that fixes nitrogen in soil?

cyanobacteria, rhizobium

who was George Washington Carver?

created crop rotation for nitrogen cycle

- peanuts replace nitrogen fixing bacteria

sulfur cycle process?

comes from decomposition, volcanic activity, and the burning of fossil fuels

- causes acid rain (falls into lakes, oceans, causing pH levels to rise)

what are Earth's biomes composed of?

terrestrial or aquatic biomes

what are tropical rainforests?

biome found near the equator categorized by stable temperatures with abundant & seasonal rainfall, forming trees & structurally important vegetation

- most diverse terrestrial biome

what are savannas?

biome located in the tropics with an extended dry season; characterized by a grass WITH scattered/distributed trees

what are subtropical deserts?

biome found in the subtropics with hot daily temperatures, very low/unpredictable precipitation, characterized by a limited dry-adapted vegetation

what are chapparals (scrub forests)?

biome found in temperate costal regions characterized by low trees and dry-adapted shrubs & forbs

- South coast of Australia; needs fire to rejuvenate

what are temperate grasslands?

biome dominated by grasses and herbaceous plants due to low precipitation, periodic fires, and grazing

- typically found throughout central North America

- grasses with few trees; has rich soil

what are temperate forests?

biome found in temperate regions with moderate rainfall & dominated structurally by deciduous (shedding) trees

- most common biome in North America

- precipitation is relatively constant

- less diversity than tropical rainforests

what are boreal/taiga forests?

biome found in temperate and subarctic regions characterized by short growing seasons and dominated structurally by PINE TREES

- common in high latitude locations where its colder (Mt. Charleston ex.)

what are arctic tundras?

biome characterized by low avg. temperatures, brief growing seasons, presence of permafrost, and limited precipitation largely in the form of snow; dominant vegetation include low shrubs, mosses, small herbaceous plants

what is permafrost?

a perennially frozen portion of the arctic tundra soil; slowly decays organic matter

what is the desert rain shadow effect?

mountains force air (cloud) upwards, forcing water (rain) out before descending upon the mountain, drying the other side of the mountain (bc it has no mo rain after getting over)

what are the abiotic factors of aquatic biomes?

light, temperature, flow regime, and dissolved solids

name some of the several zones that categorize the ocean

photic/aphotic zones, intertidal zone, pelagic realm/zone, benthic realm/zone, etc...

what is the pelagic realm/zone?

all of the ocean's open water

what is the benthic realm/zone?

part of the ocean that extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor

- dead organisms (fungi, fishes, bacteria), leaving high nutrients

- not much photosynthesis

photic zone?

upper layer of the ocean water in which photosynthesis is able to take place

aphotic zone?

part of the ocean where photosynthesis can't occur

intertidal zone?

the part of the ocean that is closest to land; parts extend above the water at low tide

neritic zone?

part of the ocean that extends from low tide to the edge of the continental shelf

- highest productivity & biodiversity (has phytoplankton and other photosynthetic bacteria)

- prob contains coral reefs

oceanic zone?

part of the ocean that begins offshore where the water measures 200m deep or deeper

abyssal zone?

deepest part of the ocean at depths of 4000m or greater

- very cold w/high pressure; high nutrient content

- no photosynthetic organisms

what is a coral reef?

an ocean ridge formed by marine invertebrates living in warm shallow waters within the photic zone

- one of the most diverse biomes; over 4000 fish species inhabit it

what is the cryptofauna?

the invertebrates found within the calcium carbonate substrate of coral reefs

what are planktivores?

animals that eat plankton

what are estuaries?

region where fresh water & salt water mix where a river discharges into an ocean or sea

- contains halophyte plant species (adapted to salt content while originally fresh water species)

what are ecosystem services?

the human benefits provided by natural ecosystems

- drinking, crops, sanitation

what is algal bloom?

a rapid increase of algae in an aquatic system

- too much nitrogen/phosphorus in a lake/pond; sucks up oxygen and kills organisms

what is source water?

point of origin of a river or stream

what is a channel?

the bed and banks of a river/stream (its width)

what are wetlands?

environments in which the soil is either permanently or periodically saturated with water

- types of wetlands: marshes, swamps, bogs, mudflats, salt marshes

what is emergent vegetation?

plants with roots in water but extend above it

what are some of the parts of marine (ocean) biomes?

ocean, coral reefs, estuaries costal areas