Post on 12-May-2018
Ecology: The study of living organisms and their environment
Who studies Ecology? Ecologists
Characteristics of Life
Made of one or more cells Organized
o Arranged in an orderly way with structures that have specific jobs
Grow and developo Increase in size and complexity over time
Reproduceo Produce offspring
Respond to Stimulio React to their environment
Require Energy Maintain Homeostasis
o Have an internal balance
Ecosystem Organization
Biotic Factors Abiotic Factors
Living parts of the environment
Nonliving parts of the environment
Animals Dirt
Plants Temperature
Levels of Organization
1. Population- 2 or more groups of organisms of the same speciesa. Ex: caribou
2. Community- 2 or more different populationsa. Ex: caribou, rabbits, owls
3. Ecosystem- Interaction between living and nonliving thingsa. Ex: bears, eagles, sun, water
4. Biomes- groups of ecosystems that have the same climatea. Ex: Evergreen Forest
5. Biosphere- total area that can support lifea. Sphere= circle Bio=life
Ecological Succession
Ecological Succession- change in an ecosystem when one community replaces another because of changing abiotic and biotic factors
Primary Succession- slow establishment of a community in a rocky area
Lichens break down rock and decompose to form soil (pioneer species)
Climax Community- A stable, mature community
Secondary Succession- return of native species to a habitat after a
disturbance
Biomes
Tundra- treeless biome with layer of permafrost below the surface
Short grasses, shrubs, caribou, polar bears, wolves, trout
Cold and dark much of the year
Boreal Forest (Taiga)- dense evergreen forest
Spruce and fir trees, deciduous trees, small shrubs, moose, beavers, deer
Short summers; long, cold winters
Temperate Forest- mainly deciduous trees, well-defined seasons
Oak, beech, maple trees, squirrels, rabbits, deer, foxes
Summers are hot, winters are cold
Grassland- fertile soils with lots of grasses
Droughts, grazing animals, grasses and herbs, horses
Summers are hot, winters cold, fires possible
Desert- more evaporation than precipitation
Cacti, succulents, lizards, bobcats, tortoises
Daily fluctuations in temperatures, low rainfall
Tropical Rain Forest- warm temperatures and lots of rain
Most biodiverse, tall trees, monkeys, tigers, toucans, sloths
Humid and rainy all year
Human Impacts on the Ecosystem
Negative impacts humans have on the Earth:
Habitat Loss- removal of the habitat
o Effect: no place for organisms to liveo Ex: Deforestation
Habitat Degradation- to make unlivableo Ex: Pollution
Acid Rain- rain that has a high concentration of acids because of air pollution
Ozone Depletion- less ozoneo Effect: more harmful UV rays reach Earth. Ozone depletion
can be caused by CFCs Greenhouse Effect- heat is trapped by gasses (like CO2) in the
atmosphere causing global warmingo This happens naturally
Factors that Increase Global Warming
Burn fossil fuels
Cut trees Drive cars
**If we keep adding carbon to the atmosphere the temperature will increase**
Factors that Decrease Global Warming
Plant trees Carpool Fuel efficient cars
Human Impact on Ecosystems (Continued)
Invasive Species- come from another area, they do not belong, have no predators, and reproduce and spread out of control
Pesticides- chemical substance that kills pests, can cause pesticide resistanceo DDT and Eagles
Pesticide Resistance-ability for insects to become resistant to a pesticide, causing humans to use something strongero Alternative to Pesticides
Biological Pest Control- use of living organisms or naturally produced chemicals to control pests
o Biomagnification- substances that do not break down naturally that can be passed up the food chain
Energy
All living things must have energy in order to maintain homeostasiso Homeostasis-an internal balance
# 1 energy source = SUN Autotroph- makes own food, gets energy from sun
o Photosynthesis- use sunlight Ex: Plants
o Chemosynthesis- use chemicals Ex: bacteria in the deep ocean autotrophs
Types of Heterotrophs
1. Herbivore: eats plantsa. Deer, Cows
2. Carnivore: eats meata. Lions
3. Omnivore: eats both plants and meata. Bears (eat berries and fish)
4. Scavengers: eat dead thingsa. Buzzards
5. Decomposers: biodegrade (break down) thingsa. Bacteria in a dumpster
Energy
Food Chain- The way energy is passed in an ecosystem, the feeding systemo Only 10% of energy goes to the next level. The rest is either
used or lost as heato As you move up the pyramid, energy is lost so the amount of
energy decreaseso Energy must be replaced by the suno Trophic Level= Energy Level
Ecological Pyramid- shows the amount of energy or matter contained within each trophic level
Pyramids show the transfer of:o Energy
o Biomass- amount of living matter at each trophic level
o Population Size- relative # of organisms at each trophic level
Energy (Cont.)
Only 10% of the available energy contained in one trophic level gets passed on to the next trophic levelo Ex: Algae (1000 cal- energy)minnow (100 cal) blue gill (10
cal) Where does the rest (90%) of that energy go?
o Lost as heato Not all of the food is eateno Not all of the food is digestedo Entire level cannot be consumed
Food Webs
Food Web- many interconnected food chainso The arrow in a food web ALWAYS points TOWARD the
CONSUMER in the direction of the flow of energy
Producer: - grass Primary Consumer-
grasshopper Secondary Consumer- Bird Tertiary Consumer- Hawk
Matter is Recycled
Water Cycle
Carbon Cycle
A. Plants take in CO2 (Photosynthesis)
B. We breathe in O2 from plants
C. We eat plants
D. We breathe out CO2 (Cellular Respiration)
Pollution Bad CO2 into air
Other Sources of Carbon:
Decomposition of dead organisms
Erosion and volcanoes
Burning Fossil Fuels
Cutting and burning trees
Carbon Cycle (Cont.)
Organisms/ Input Effects
CO2
A
O2
D
B
CFood
Plants (autotrophs) Photosynthesis (uses carbon)
Decomposers
Fungi/Bacteria
Carbon released when things die
Animals Cellular Respiration (release carbon)
Burning of Fossil fuels
(Dead organisms become coal, gas, oil)
Carbon Released
What would happen if decomposers were removed from the carbon cycle? The amount of carbon in the atmosphere would decrease
Nitrogen Cycle
Nitrogen gas in soil Enters in root nodules of plants like legumes Converted to ammonia by nitrogen-fixing bacteria Plant uses ammonia to build protein An animal converts plant protein to animal protein Animal carcass decomposed into nitrates (nitrification) Some nitrates broken down by soil bacteria (denitrification)
The Phosphorus Cycle
Short Term and Long-Term Cycles Short Term Cycle
o Phosphates in watero Producers take up phosphates from soilo Consumers eat phosphates in plantso Consumers die/ produce waste and decomposers break down
phosphorus Long Term Cycle
o Phosphorus used to make up rocks
What shapes an Ecosystem
Competition- fighting over resources
Habitat Niche
Where it lives What it does- its job
Ex: in a tree Ex: collect acorns
Niche includes
Type of food organism eats
Physical conditions needed to survive (ex. Place to hibernate)
How it reproduces (lays eggs in winter)
Competition is reduced by having organisms with different niches (needs)
Predator/Prey (Predation)
Predator: eats
Prey: gets eaten
It’s a cycle: prey up, predator up, then prey gets eaten, levels down,
predator down from lack of food, then back to beginning as prey
makes a comeback
Density Dependent Factor depends on the size of the population
Density Independent Factor does not depend on the size of the
population
Symbiosis living together, nothing dies
Mutualism- 2 species (both) benefit
Parasitism- 1 benefits, 1 harmed
Commensalism- 1 species benefits, 1
not benefited or harmed
Tropisms
Tropism- plants adjust growth in response to environmental stimuli
Gravitropism- (geotropism) a growth response to gravity
Phototropism- when stems/leaves adjust to the direction of growth in response to light
Thigmotropism- plants shift a direction of growth as they touch
Population Ecology
3 important factors affecting a population are:o Geographic distributiono Density- # of organisms/ areao Growth rate
Population growtho 3 factors that affect the population size
Number of births Number of deaths Number entering or leaving the population
Populations grow exponentially under the best conditions with unlimited resources results in a J-shaped curveo Growth initially starts slow, there are few reproductive
individualso Growth then begins to increase rapidly (ex. Increase due to
medical technology)o J-Curve- slow in beginning, then speeds up
Limits on the Environment
Populations are controlled by limiting factors Results in an S-Shaped Curve Carrying Capacity- maximum number of organisms an environment
can support indefinitelyo Above CC too many, some dieo Below CC room for more
Limiting Factor- anything that prevents some things from living in an areao Abiotic: temperature, rain, soilo Biotic: food, predators