3.1 – What is Ecology? Interactions and Interdependence Ecology – the study of interactions...
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Transcript of 3.1 – What is Ecology? Interactions and Interdependence Ecology – the study of interactions...
Biology
Chapter3
3.1 – What is Ecology?
Interactions and Interdependence
• Ecology – the study of interactions among organisms and their environment
• Oikos (ec) – Greek word meaning house
• Ology – means study of
Levels of Organization
• The levels of organization that ecologists study include:
• Individuals
• Species – group of similar organisms that can breed and produce fertile offspring
• Populations – group of individuals of the same species that live in the same area and interbreed
• Communities – different populations that live together in a defined area
• Ecosystem – The interaction of all the organisms and the environment in a given area
• Biome – a group of ecosystems that have the same climate
• Biosphere – part of Earth in which life exists including land, water and atmosphere
• It extends about 8km above the Earth’s surface to about 11km below
• If you could shrink earth to the size of an apple, the biosphere would be thinner than the apple’s peel
Biotic and Abiotic Factors
• Biotic Factors – all the living organisms in an ecosystem
• Example: tree, bird, bacteria, fungi
• Abiotic Factors – nonliving factors in an ecosystems
• Example: temperature, precipitation, wind, soil, sunlight, humidity
• Habitat – area where an organism lives
• Includes both biotic and abiotic factors
• Niche – the role and position a species has in its environment
• No two species can share the same niche in the same habitat
3.2 – Energy Flow
• Sunlight is the main energy source for life
• Autotrophs
• Make their own energy
• Convert sun energy into chemical energy
• Also called a producer
• Plants are the main autotrophs on land
• Algae are the main autotrophs in water
• Some autotrophs can produce food in the absence of light
• Chemoautotrophs – organisms use chemical energy to produce carbohydrates
• Performed by several types of bacteria
• Live in…
• Volcanic vents
• Deep ocean
• Hot springs
• Marshes
• Heterotrophs
• Get energy from other organisms
• Unable to make its own energy
• Also called consumers
• Types of Heterotrophs
• Herbivores
• Eats only plants
• Example: cows, deer, rabbits, bees, elephants, squirrels
• Carnivores
• Eats only animals
• Example: snakes, dogs, lions, crocodiles
• Omnivores
• Eats plants and animals
• Example: humans, bears, crows
• Detrivores
• Eat decomposing bits of organic matter
• Example: mites, earthworms, snails, crabs
• Decomposers
• Break down organic matter
• Example: bacteria and fungi
• Scavenger
• Ingest nonliving plants and animals
• Example: vulture, termite, beetle
Feeding Relationships
• Food Chain – a straight line series of steps by which energy is stored and passed on to higher trophic levels
• Food Web – a network of crossing interlinked food chains that shows all the possible feeding relationships at each trophic level
• Energy is passed through no more than four or five trophic levels
• Trophic Levels – step in a food chain or food wed
• Plants and other producers are 1st trophic level
• Consumers make up the 2nd, 3rd, or higher trophic levels
• Each consumer depends on the trophic level below it for energy
• Energy is transferred from one trophic level to another and is never 100%
• At each trophic level only 10% of the energy taken in by the organism is stored. The rest is used up during metabolism to process the energy
Ecological Pyramids
• Ecological Pyramid – a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web
• Example: Ecological Pyramids
Community Interactions
• Competition – occurs when organisms of the same or different species attempt to use the same resources
• Predator – eat other animals
• Prey – the animal a predator eats
• Symbiosis – relationship in which two species live closely together
• Three Types of Symbiosis
• Mutualism
• Both species benefit from the relationship
• Example: plants and bacteria on roots
Shark and fish
• Commensalism
• One organism benefits and the other is neither helped nor harmed
• Example: tree and bird nest
• Parasitism
• One organism lives on or inside another organism and harms it
• Example: tick, ringworm
Fig. 48.12, p. 862
3-3 Cycles of Matter
• Biogeochemical Cycles – process in which elements, chemical, and other forms of matter are passed from one organism to another and from one part of the biosphere to another
The Water Cycle
• Evaporation – process by which water changes from a liquid to a gas
• Transpiration – loss of water from plants by the process of evaporation
• Condensation – water vapor changes to a liquid
• Precipitation – water returns to the earth (rain, snow, hail)
The Carbon Cycle
• Carbon is released into the atmosphere by…
• Respiration
• Burning fossil fuels
• Volcanic activity
• Burning trees
• Carbon is taken out of the atmosphere by…
• Photosynthesis performed by plants
• Carbon is released into the ground by…
• Decomposition
• Carbon is taken out of the ground by…
• Mining oil and coal
• Roots of plants
OilCoal Root Uptake
Decomposition
Photosynthesis
RespirationBurning Trees
Burning Fossil Fuels
Volcanic Activity
CO2
Organism eats plants
C6H12O6
Nitrogen Cycle
• Gaseous nitrogen (N2)makes up 80% of the atmosphere
• Nitrogen Fixation
• Bacteria convert N2 to ammonia (NH3)
• This dissolves forming ammonium (NH4)
• Ammonification
• Bacteria degrade nitrogenous wastes and remains of organisms.
• Convert NH3 to NH4
• Nitrification
• Bacteria convert NH4 to nitrite (NO2) to nitrate (NO3)
• Denitrification
• Bacteria convert extra nitrates or nitrites (NO3, NO2) to N2
• N2 is released back into the atmosphere
Gaseous Nitrogen
N2
Ammonification
Bacteria convert wastes and decomposing organics to
NH3 → NH4
Nitrogen Fixation
Bacteria in the soil convert
N2 → NH3 → NH4
Denitrification
Bacteria convert
NO3 → N2
Nitrification
Bacteria convert
NH4 → NO2 → NO3
Autotrophs can take up NH4 and NO3
• Humans are harming the nitrogen cycle by:
• Deforestation
• Conversion of grasslands for agriculture
• Sewage enters waterways
• Fossil fuel burning
• Vehicles having combustion engines releases NO2
4-2 What Shapes an Ecosystem?
• Ecological Succession
• Succession – changes that occurs in a community over time
• Pioneer Species – first species to populate the area
• Climax Community – a stable mature community that undergoes little or no change in species
• Two Types of Succession
• 1. Primary Succession
• Succession that occurs on surfaces where no soil exists
• Example: rock surfaces formed after volcanoes erupt
• Secondary Succession
• Succession following a disturbance that destroys a community without destroying the soil
• Because soil already exists, secondary succession usually takes less time than primary succession
• Example: fires, floods, farming, construction, hurricanes, tornadoes