4 - Ecology

Ecology

studies how living things interact and their relationship with the environment

Biotic factor

Biotic factors are living organisms in an environment

Abiotic factor

Abiotic factors are non-living things in an environment

Species

A group of similar organisms that can inter breed and produce fertile offspring

Habitat

the usual environment in which a species normally lives in

Population

a group of organisms of the same species in the same area at the same time

Community

a group of population living and interacting with each other in the same area, a community and its abiotic factors

Ecosystem

A community of organisms and their abiotic environment

Nutrients

a substance that provides organic compounds or energy that are required for growth and homeostasis

Autotroph

An organism that makes its own food, synthesizes its own organic molecules from inorganic substances, thus it is a producer

Autotroph example

plants can create glucose from inorganic CO2 via photosynthesis

Heterotroph

An organism that cannot make its own food, thus must obtain organic molecules from others, consumers eat producers

Consumer

An organism that obtains energy by feeding on other organisms

Detritovore

an organism that ingests detritus or non-living organic matter

Saprotroph

an organism that secretes digestive enzymes onto non-living organic matter and absorbs the products after digestion, ax example is fungi

Food chain

A series of steps in which organisms transfer energy by eating and being eaten by other organisms

Food web

a network of interaction between multiple food chains

Food chain example

Producer: grass

Primary consumer: grasshopper

Secondary consumer: bird

Tertiary consumer: snake

Quaternary consumer: hawk

Nutrient cycling

the recycling of organic matter into inorganic and vice versa. Autotrophs convert inorganics into organics, heterotrophs ingest organics for growth and respiration releasing inorganics, saprotrophs decompose inorganics into soil, autotrophs use raw materials from soil.

Trophic levels

the level or step occupied by a particular organism in a food chain; producer, primary, secondary, tertiary, quaternary consumers.

Energy source

Light is the initial energy source for most food chains, absorbed by producers and converted into chemical energy via photosynthesis, some ecosystems use chemoautotrophs

Energy loss in ecosystems

only 10% of energy is transferred from one trophic level to another, 90% is lost as heat as organisms cannot convert heat into other energy forms, or material is not consumed

Energy loss in organisms

Energy produced by an organism can be made in kinetic energy, electrical energy, light energy but they all release heat energy and living organisms cannot turn heat into usable energy, and thus energy is lost from the ecosystem

Energy loss in respiration

Organic molecules store release energy as ATP through cell respiration in living organisms for growth and homeostasis and heat is released from the organism

Decomposers

organisms that recycle non-living things or dead remains, such as fungi and bacteria

Energy in Ecosystems

starts with solar energy and moves to producers then consumers from one level to another

Energy loss and biomass

As energy is lost, higher trophic levels store less energy as carbon compounds and have less biomass, thus get less energy or biomass and need more to have sufficient amounts expending more energy and biomass on hunting.

Atmosphere

A mixture of gases above Earth's surface, the atmosphere functions to retain heat at night and prevent temperature changes so organisms would survive

Lithosphere

the solid layer of the earth, the crust and the mantle

Hydrosphere

the total water on earth, oceans, lakes, rivers...

Biosphere

the sum of all life on Earth

Carbon cycle

The biogeochemical exchange of carbon between the 4 different spheres of the Earth

Carbon cycle exchanges

Carbon can be exchanged between atmosphere gases, like CO2 and CH4, oceanic carbonates, like HCO3 and CaCO3 in corals and shells, organics like carbohydrates, lipids, proteins; and non-living matter, like detritus

Carbon cycle processes

photosynthesis - removes CO2 from atmosphere and forms organics in producers, respiration - releases CO2 into atmosphere when organics are digested, decomposition - releases carbon products into atmosphere or sediments, combustion - releases carbon gases by burning hydrocarbons, lithication - compaction of carbon-rich sediments into fossils, gaseous dissolution - exchange of carbon gases between ocean and atmosphere

CO2 and autotrophs

Autotrophs, like plants convert inorganic CO2 into organics via photosynthesis, thus the CO2 conc. within an organism should be low and higher around it so it could passively diffuse. Uptake of CO2 and production of CO2 should be balanced.

Compensation point

the net CO2 assimilation is zero, intake and output is the same

CO2 and respiration

Cell respiration breaks down organics and produces CO2 which builds in respiring tissue and creates a conc. gradient allowing for removal by passive diffusion.

Aquatic conversion

CO2 dissolves in water, but some combines with water forming carbonic acid which dissociates into hydrogen carbonate ions and hydrogen ions, thus increasing acidity.

CO2 and ocean acidification

Hydrogen carbonate ions contact rocks and acquire metal ions forming CaCO3 which forms the hard coral exoskeleton and mollusk shells, as they die the components fossilize into limestone.

Methane

Methane is produced in anaerobic conditions that contain methanogenic archaeans, such as swamps or ruminant animals, as a by-product

Methane accumulation

Methane can accumulate and form natural gas deposits when organic matter is buried in anoxic conditions, or accumulate in the atmosphere from rising numbers of cattle

methane oxidation

After 12 years methane oxidizes into CO2 and water, thus methane levels are not large

Peat formation

Peat forms when organic matter cannot be fully decomposed by saprotrophs in waterlogged soils as they lack oxygen, and form organic acids via anaerobic respiration. Carbon-rich matter remains in the soil and forms peat.

Coal formation

Peat deposits are compressed under sediments where heat and pressure remove impurities and moisture, remaining high carbon conc. undergoes chemical transformation into coal.

Oil and Natural Gas Formation

dead marine organisms accumulate on ocean floor and sediments sit on top creating anoxic conditions preventing decomposition. Organics are heated forming hydrocarbons which become oil and gas, eventually forced out of porous rocks to form deposits. Takes millions of years.

Carbon fluxes

the exchange rate of carbon between different earth spheres, measured in gigatons

CO2 levels

CO2 levels fluctuate as photosynthesis increases in summer, CO2 levels conform to the northern hemisphere as there is more land mass, CO2 levels increase since the industrial revolution, and are currently at their highest levels

Greenhouse gases

Greenhouse gases absorb and emit long-wave radiation trapping heat within the atmosphere, CO2 and water vapor have the largest warming effect, others are Methane and nitrogen oxides

Greenhouse gas factors

ability to absorb long-wave radiation as gases with greater ability warm more, gas conc. as more gas more warmth

greenhouse effect process

Solar energy shines down on the Earth, some bounces back to space, but the rest is absorbed by the land, oceans and atmosphere, warming the surface, then re-emitted back at longer infrared wavelengths where some goes to space, but some is absorbed by trace atmospheric gases.

Greenhouse effect definition

The natural process where greenhouse gases trap and retain heat within the atmosphere to regulate temperature, thus preventing harsh changes in temp. at night

Greenhouse effect human

Greenhouse gases are naturally present, but increased by humans. CO2, NO2 and methane absorbs infrared wavelengths "exciting" the gas and warming the atmosphere, where energy is re-emitted back again, some bounces back to space some is absorbed. As greenhouse gases increase in the atmosphere the temperature increases.

Climate change consequences

Polar cap shrinking, melting permafrost releases methane, species migration, more frequent extreme weather conditions, changes to ocean currents

Permafrost

Permanently frozen ground, if it melts it releases methane as non-living organisms under it decompose

precautionary principle

states that if individuals are unsure about something that could cause harm to the environment, they must provide scientific proof that it will not cause harm

binomial nomenclature

Classification system where a species is assigned a two names, first name is the genus, second is the species, always italicized or underlined

Taxonomy Hierarchy

Kingdom, Phylum, Class, Order, Family, Genus, Species, Mnemonic "Kinky Professors Cause Older Females Genital Spasms"

Human Taxonomy

K - Animalia

P - Chordata

C - Mammalia

O - Primates

F - Hominidae

G - Homo

S - Homo sapiens

Mesocosm

a self-sustainable sealed ecosystem that contains biotic and abiotic factors, light and mud, autotrophs to produce carbon and oxygen, consumers, detritivores, saprotrophs to recycle remains or nutrients

What are Mesocosms used for?

to observe how smaller ecosystems react to environmental changes, by manipulating the environment variables

ecosystem sustainability

ecosystems can be sustainable if; nutrients can be recycled, there's an available energy source, and waste products are detoxified

chi squared test of independence

Tests the independence of two categorical variables using counts in a contingency table.

Quadrat sampling

square or rectangular plot of land, a quadrat, marked off at random to isolate a sample and determine the percentage of vegetation and animals occurring within the marked area.