Ecology Flashcards
Ecology
The study of the interactions of organisms with their physical environment & with each other
Population
Group of individuals of 1 species in 1 area who can interbreed & interact with each other
Community
Consists of all organisms living in 1 area
Populations that interact with environment & with each other
Ecosystem
All organisms in a given area as well as the abiotic (nonliving factors) with which they interact
Abiotic Factors
Nonliving factors
Include temperature, water, sunlight, wind, rocks & soil
Biotic Factors
All organisms with which an organisms might react
Birds, prey, insects, predators & parasites
Biosphere
The global ecosystem
Niche
What an organisms eat & needs to survive
Size (in population)
Total number of individuals in a population, 4 limits:
Number of births & deaths, immigration & emigration
Density (in population)
Number of individuals per unit area/volume
Use “mark & recapture” technique
Dispersion (in population)
Pattern of spacing of individuals within area the population inhabits
Clumped, uniform, random
Biotic Potential
The maximum rate at which a population could increase under ideal conditions
Affected By: age, life span, reproductive periods, offspring
Exponential Growth
Unrestrained/exponential growth with no predation, parasitism, competition, immigration or emigration in environment with unlimited resources
Carrying Capacity (K)
A limit to the number of individuals that can occupy 1 area at a particular time
Can change as environmental conditions change
Limiting Factors
Those factor that limit population growth;
density-dependent & density-independent
Density-Dependent Factors
Limiting Factor
Those factors that increase directly as the population density increases composition for food, buildup of wastes, predation & disease
Density-Independent Factors
Limiting Factor
Those factors whose occurrence is unrelated to the population density
Earthquakes, storms, naturally occurring fires & floods
Competition
2 possible outcomes, 1 will evolve & 1 will become extinct
“2 species cannot coexist in a community if they share a niche, that is, if they compete for the same resources”
Predation
Animal eating another, or animal eating plants
Aposematic Coloration
Defense against predation
Bright colors warns possible predators to avoid them
Batesian Mimicry
Defense against predation
Harmless butterfly looks like poisonous one
Mullerian Mimicry
Defense against predation
2/more poisonous species resemble each other & gain an advantage from their combined numbers
Carnivores
Feeding
Eat other animals
Herbivores
Feeding
Eat plants
Detritivores
Feeding
Eat dead plants/animals
Mutualism
Relationship based of feeding behaviors
Both organisms beneift, +/+
Commensalism
Relationship based of feeding behaviors
One organisms benefits, other is neither helped/harmed, +/0
Parasitism
Relationship based of feeding behaviors
Parasite benefits, host is harmed, +/-
Food Chain
The pathway along which energy is transferred from one trophic/feeding level to another
Producers (Food Chain)
Convert light energy to chemical bond energy - have greatest biomass of any trophic level
Primary Consumers (Food Chain)
Eat producers - are herbivores
Secondary Consumers (Food Chain)
Eat primary consumers - are carnivores
Tertiary Consumers (Food Chain)
Eat secondary consumers - are carnivores
Top of food chain, fewer than any organisms of food chain
Productivity
The rate at which an organic matter is created by producers
When ecologists study energy transformations within ecosystems
Gross Primary Productivity
The amount of energy converted to chemical energy by photosynthesis per unit time in an ecosystem
Net Primary Production
The gross primary productivity minus the energy used by the primary producers for respiration
Biological Magnification
Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies than those at lower trophic levels
Decomposers
Organisms that play a vital role in ecosystem & that recycle dead organic matter
Biomes
Very large regions of Earth whose distribution depends on amount of rainfall & temperature in an area
Marine (Biome)
Largest biome
Most stable with temp. that vary little & can absorb lots of heat
Provides most of Earth’s food & oxygen
Tropical Rainforest (Biome)
Greatest diversty of animal species
Near equator, abundant rainfall with high humidity & stable temp.
Cover 4% of Earth, >20% of Earth’s net carbon fixation
Desert
Experience most extreme fluctuations in temperature of any biome, hot days & cold nights
<10 in. rainfall/year
Temperate Grasslands
Cover huge areas in both temperate & tropical regions
Low annual rainfall & uneven occurence so inhospitable for forests
Temperate Deciduous Forest
Northeast America, south of taiga - trees that drop leaves in winter
Vertical stratification of animals - some on ground, treetops,…
Rich soil due to decomposition of leaf litter
Conifer Forest - Taiga or Boreal Forest
Northern areas, largest territorial biomes with seasonal temperatures (more than 70C)
Dominated by evergreens, dotted with lakes, ponds,…
Abundance of rainfall, trees dominated landscape, heavy snowfall
Tundra (Biome)
Far northern parts of North America, Europe, Asia
Permafrost, permanently frozen subsoil
Frozen desert, little rainfall that cant penetrate frozen ground
Treeless, many lakes, ponds,…
Low number of different species
Water Cycle
Water evaporates from Earth, forms clouds, rains over oceans & land
Carbon Cycle
Process of photosynthesis & respiration
Nitrogen Fixing Bacteria
Convert free nitrogen (N2) into ammonium ion (NH4)
Nitrifying Bacteria
Convert ammonium ion (NH4) into nitrites (NO2) & then into nitrates (NO3)
Denitrifying Bacteria
Convert nitrates (NO3) into free atmospheric nitrogen (N)
Decomposers
Bacteria that break down dead organic matter, into ammonia (NH4)
Eutrophication
Process that cause a runoff from sewage & manure from pastures increase in lakes & cause excessive growth of algae & other plants
Greenhouse Effect
Carbon dioxde & water vapor in air absorb much of infrared radiation reflecting off Earth, causing average temperature on Earth to rise
Global Warming
Increase in average temperature of Earth, due to greenhouse effect
Pesticides
Chemicals that kill undesirable organisms
Save lives by increasing food production & killing animals that carry/cause disease
Mark & Recapture
Organisms are captured, tagged & then released
Some time later, the same process is repeated & a special formula is used to determine the density of the population
Factors that can cause a population crash
Predation, parasitism, severe competition, an end to resources, and/or too much waste that poisons the environment
r-Strategists
Opportunistic, reproduce rapidly when the environment is uncrowded & resources are vast
K-Strategists
Tend to maximize population size near the carrying capacity for an environment
Competitive Exclusion Principle
2 species cannot coexist in a community if they share a niche, that is, if they compete for the same resources
Resource Partitioning
Instead of extinction, a species will evolve through natural selection to exploit different resources
Character Displacement
Instead of extinction
Divergence of adaption, like finches on Galapagos Islands
Diatoms (Producer)
Photosynthetic algae that drift in the oceans
Phytoplankton (Producer)
Algae & photosynthetic bacteria that drift passively in aquatic environment
Ecological Succession
Process of sequential rebuilding of the ecosystem after drastic destruction of a community or an entire ecosystem
Primary Ecological Succession
Soil building
Rebuilding in a lifeless area where even soil has been removed
Pioneer Organisms
First organisms to inhabit a barren area
Climax Community
Final stable community that remains until another blowout
Blowout
A disaster that destroys the ecosystem
Secondary Succession
When an existing community has been cleared by some disturbance that leaves the soil intact
Epiphytes
Photosynthetic plants that grow on other trees rather than supporting themselves
Vertical Stratification
Some species live on ground, some in low branches, some in the treetops
Eutrophication
(as photosynthetic organisms die) FIRST
Organic material accumulates on the lake bottom & reduce the depth of the lake
Eutrophication
(as photosynthetic organisms die) SECOND
Detritivores use up oxygen as they decompose the dead organic matter
Impossible for fish to live, decomposers expand activity & oxygen decrease until lake disappears
Acid Rain
Nitrogen & sulfur pollutants in the air turn into nitric, nitrous, sulfurous & sulfuric acids
Cause pH of rain to be less than 5.6
Biological Control
Crop Rotation
Introduce natural enemies of the pests
Use natural plant toxins instead of synthetic ones
Use insect birth control
