Species & Populations Flashcards
Ecology
Study of living & non-living parts that interact within an ecosystem
Ecosystem
Community of interdependent organisms & their interactions with the phyiscal environment
Pyramid
- organisms
- species
- populations
- community
- ecosystems
Biosphere
Global ecosystem composed of living organisms and the abiotic factors from which they derive energy and nutrients
Organism
An individual animal, plant, or single celled life form which goes through life processes
Species
A group of organisms sharing common characteristics that are able to reproduce and produce fertile offspring
Binomal Nomenclature
Used by scientists to identify a specfiic species.
Always underlined or in italics.
Genus is capitalized.
Species is lower case
Dichotomous Key
Used to identify organisms
Endemic Species
Species found only in 1 specific region of the Earth and are most vulnerable to die out
EX: kangaroos (Australia), Lemurs (Madagascar)
Population
A specific species in 1 area.
EX: African Elephant in the bush of Liwandi, Bottlenose dolphins of the Indian River Lagoon
Community
Several populations within 1 area
Biotic Factors
All the living components of an ecosystem
EX: plants, bacteria, fungi, animals
Abiotic Factors
Non-living physical factors in an ecosytem that may influence an organism or system
EX: temperature, salinity, pH, light
Habitat
The place where an organism lives that provides them with the necessary components of life
EX: food, water, shelter
Niche
The role “job” of the organism
EX: plants make food for rest of food chain, tigers keep herbivore population under control
Fundamental Niche
The entire range of condiitons in which a species could live
Realized Niche
The actual conditions under which the species lives (usually due to competition- limiting factors)
Competition
Demand for a limited resource by multiple organisms
“Competitive Exclusion Principle”
States that 2 species cannot coexist in a community if they share a niche, or compete for the same resources
Intraspecific Competition
Competition within 1 species
EX: tree sapplings compete for light, flamingoes compete for mates
Interspecific Competition
Competition between different species
EX: a puma vs a brown bear competing for salmon
Mark & Recapture Method
Used for aquatic & terrestrial animals.
1. Camera / traps used.
2. Captured animals are marked & released.
3. After a bit of time, traps are set again.
4. Repeat recapture as many times as possible.
Should not affect survival / fitness of organism.
The Lincoln Index
Assuming no deaths, births, immigration, emmigration.
N = (# marked in 1st catch) x (total # in 2nd catch)
/
(# of recaptures in 2nd catch)
Quadrat Method
Used for plants & sessile organisms.
- Mark out grid line along 2 edges of area
- Use calculator / tables to generate 2 random numbers to use as coordinates & place quadrat on ground with corner at coordinates
- Count individuals inside quadrat
- Repeat steps 2&3 as many times as possible
- Measure total size of area occupied in square meters.
- Caluclate mean number of indivuals per quadrat
- Calculate population size with equation
Quadrat Method Equation
N = (mean # per quadrat) x (total area)
/
(area of each quadrat)
Density
of individuals per unit area
Frequency
Proportion of quadrats sampled that contain your species.
Assessment of patchiness of distribution.
% Cover
Space within the quadrat occupied by each species.
Distinguishes the larger and smaller species.
Population Characteristics
- Size (# of individuals)
- Density (# of indivuals in a certain space)
- Dispersion (spatial pattren of individuals: random, uniformed, clumped)
- Age distribution (proportion of each age)
Population Dynamics
Changes of populations in response to environmental stress & change
Keystone Species
Species on which other species in an ecosystem largely depend
Foundation Species
Species that has strong role in structuring a community
Flagship Species
Species selected to act as ambassador, icon, symbol for defined habitat, issue, campaign, environmental cause
Symbiotic Relationships
2 organisms live closely with each other & at least 1 benefits
Mutualism
Both organisms benefit from each other
EX: termites & microorganisms in their stomach
Parasitism
1 organism benefits while the other is harmed
EX: tapeworm & human intestines
Commensalism
1 organism benefits and the other is unaffected
EX: pilot fish & shark
Predation
1 animal feeding on another
EX: Lion eating antelope
Carrying Capacity
Maximum number of organisms of a single species that an ecosystem can support
Limiting Factors
- Birth
- Death
- Immigration
- Emigration
Population changes = (birth + immigration) - (death + emigration)
Density-dependent
Limiting factors that increase as density increases.
EX: competition for food, waste build up, predation, disease
Density-independent
Limiting factors whose occurence are not related to population density.
EX: extreme cold or heat, wildfires, flooding, drought, vehicle accidents
Biotic Potential
Capacity for growth.
Perfect case scenario.
Environmental Resistance
All factors which limit growth of populations
Exponential Growth
J Curve.
Occurs with few or no resource limitations.
Logistic Growth
- Exponential growth
- Slower growth
- Then plateau at carrying capacity
S Curve
Population will fluctuate around carrying capacity
Negative Feedback
Response that causes output of system to be lessened so feedback tends to stabilize system
R-selected Species
Opportunists. Reproduce early. Many offspring, few survive. Common after disturbance but poor competitors. EX: rats, roaches
K-selected Species
Competitiors. Reproduce late. Few offspring, most survive. Common in stable areas, strong competitiors. EX: kangaroos, killer whales
Human Impact on Natural Populations
- Fragmenting & degrating habitats
- Simplifying natural ecosystems
- Using / destroying world primary productivity which supports all consumers
- Strengthening pest & disease populations
- Eliminating predators
- Introducing exotic species
- Overharvesting renewable resources
- Interfering with natural chemical cycling & energy flow
Environmental Stress on Organisms
- Physiological changes
- Psychological changes
- Behavior changes
- Few / no offspring
- Genetic defects
- Cancers
- Death
Environmental Stress on Populations
- Changes in population size
- Changes in age structure (old, young, weak may die)
- Survival of strains genetically resistant to stress
- Loss of genetic diversity & adaptability
- Extinction
Environmental Stresses on Ecosystem
- Distruption of biogeochemical cycles
- Habitat loss & degradation
- Lower species diveristy
- Less complex food webs
- Lower stability
- Ecosystem collapse
