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Flashcards in Ecology Deck (77):
1

Ecology

The study of the interactions of organisms with their physical environment & with each other

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Population

Group of individuals of 1 species in 1 area who can interbreed & interact with each other

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Community

Consists of all organisms living in 1 area
Populations that interact with environment & with each other

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Ecosystem

All organisms in a given area as well as the abiotic (nonliving factors) with which they interact

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Abiotic Factors

Nonliving factors
Include temperature, water, sunlight, wind, rocks & soil

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Biotic Factors

All organisms with which an organisms might react
Birds, prey, insects, predators & parasites

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Biosphere

The global ecosystem

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Niche

What an organisms eat & needs to survive

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Size (in population)

Total number of individuals in a population, 4 limits:
Number of births & deaths, immigration & emigration

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Density (in population)

Number of individuals per unit area/volume
Use "mark & recapture" technique

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Dispersion (in population)

Pattern of spacing of individuals within area the population inhabits
Clumped, uniform, random

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Biotic Potential

The maximum rate at which a population could increase under ideal conditions
Affected By: age, life span, reproductive periods, offspring

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Exponential Growth

Unrestrained/exponential growth with no predation, parasitism, competition, immigration or emigration in environment with unlimited resources

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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

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Limiting Factors

Those factor that limit population growth;
density-dependent & density-independent

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Density-Dependent Factors

Limiting Factor
Those factors that increase directly as the population density increases composition for food, buildup of wastes, predation & disease

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Density-Independent Factors

Limiting Factor
Those factors whose occurrence is unrelated to the population density
Earthquakes, storms, naturally occurring fires & floods

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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"

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Predation

Animal eating another, or animal eating plants

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Aposematic Coloration

Defense against predation
Bright colors warns possible predators to avoid them

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Batesian Mimicry

Defense against predation
Harmless butterfly looks like poisonous one

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Mullerian Mimicry

Defense against predation
2/more poisonous species resemble each other & gain an advantage from their combined numbers

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Carnivores

Feeding
Eat other animals

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Herbivores

Feeding
Eat plants

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Detritivores

Feeding
Eat dead plants/animals

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Mutualism

Relationship based of feeding behaviors
Both organisms beneift, +/+

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Commensalism

Relationship based of feeding behaviors
One organisms benefits, other is neither helped/harmed, +/0

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Parasitism

Relationship based of feeding behaviors
Parasite benefits, host is harmed, +/-

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Food Chain

The pathway along which energy is transferred from one trophic/feeding level to another

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Producers (Food Chain)

Convert light energy to chemical bond energy - have greatest biomass of any trophic level

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Primary Consumers (Food Chain)

Eat producers - are herbivores

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Secondary Consumers (Food Chain)

Eat primary consumers - are carnivores

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Tertiary Consumers (Food Chain)

Eat secondary consumers - are carnivores
Top of food chain, fewer than any organisms of food chain

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Productivity

The rate at which an organic matter is created by producers
When ecologists study energy transformations within ecosystems

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Gross Primary Productivity

The amount of energy converted to chemical energy by photosynthesis per unit time in an ecosystem

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Net Primary Production

The gross primary productivity minus the energy used by the primary producers for respiration

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Biological Magnification

Organisms at higher trophic levels have a greater concentration of accumulated toxins stored in their bodies than those at lower trophic levels

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Decomposers

Organisms that play a vital role in ecosystem & that recycle dead organic matter

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Biomes

Very large regions of Earth whose distribution depends on amount of rainfall & temperature in an area

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Marine (Biome)

Largest biome
Most stable with temp. that vary little & can absorb lots of heat
Provides most of Earth's food & oxygen

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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

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Desert

Experience most extreme fluctuations in temperature of any biome, hot days & cold nights
<10 in. rainfall/year

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Temperate Grasslands

Cover huge areas in both temperate & tropical regions
Low annual rainfall & uneven occurence so inhospitable for forests

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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

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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

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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

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Water Cycle

Water evaporates from Earth, forms clouds, rains over oceans & land

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Carbon Cycle

Process of photosynthesis & respiration

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Nitrogen Fixing Bacteria

Convert free nitrogen (N2) into ammonium ion (NH4)

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Nitrifying Bacteria

Convert ammonium ion (NH4) into nitrites (NO2) & then into nitrates (NO3)

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Denitrifying Bacteria

Convert nitrates (NO3) into free atmospheric nitrogen (N)

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Decomposers

Bacteria that break down dead organic matter, into ammonia (NH4)

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Eutrophication

Process that cause a runoff from sewage & manure from pastures increase in lakes & cause excessive growth of algae & other plants

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Greenhouse Effect

Carbon dioxde & water vapor in air absorb much of infrared radiation reflecting off Earth, causing average temperature on Earth to rise

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Global Warming

Increase in average temperature of Earth, due to greenhouse effect

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Pesticides

Chemicals that kill undesirable organisms
Save lives by increasing food production & killing animals that carry/cause disease

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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

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Factors that can cause a population crash

Predation, parasitism, severe competition, an end to resources, and/or too much waste that poisons the environment

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r-Strategists

Opportunistic, reproduce rapidly when the environment is uncrowded & resources are vast

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K-Strategists

Tend to maximize population size near the carrying capacity for an environment

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Competitive Exclusion Principle

2 species cannot coexist in a community if they share a niche, that is, if they compete for the same resources

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Resource Partitioning

Instead of extinction, a species will evolve through natural selection to exploit different resources

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Character Displacement

Instead of extinction
Divergence of adaption, like finches on Galapagos Islands

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Diatoms (Producer)

Photosynthetic algae that drift in the oceans

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Phytoplankton (Producer)

Algae & photosynthetic bacteria that drift passively in aquatic environment

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Ecological Succession

Process of sequential rebuilding of the ecosystem after drastic destruction of a community or an entire ecosystem

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Primary Ecological Succession

Soil building
Rebuilding in a lifeless area where even soil has been removed

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Pioneer Organisms

First organisms to inhabit a barren area

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Climax Community

Final stable community that remains until another blowout

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Blowout

A disaster that destroys the ecosystem

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Secondary Succession

When an existing community has been cleared by some disturbance that leaves the soil intact

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Epiphytes

Photosynthetic plants that grow on other trees rather than supporting themselves

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Vertical Stratification

Some species live on ground, some in low branches, some in the treetops

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Eutrophication
(as photosynthetic organisms die) FIRST

Organic material accumulates on the lake bottom & reduce the depth of the lake

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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

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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

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Biological Control

Crop Rotation
Introduce natural enemies of the pests
Use natural plant toxins instead of synthetic ones
Use insect birth control