Unit 2 Test Insurance: 2.4 - 2.7 Flashcards
Identify three or four conditions for which organisms have a range of tolerance.
temperature, salinity, pH, and sunlight
Describe the relationship between genetic diversity and ecological range of tolerance.
The more genetic diversity the greater the ecological range of tolerance will be since some individuals will have an extended range that is more fit for their ecosystem, which they will pass down. Less genetic diversity lessens the chance of this since there aren’t as many opportunities.
Describe ecological tolerance
Ecological tolerance are conditions that an organism can endure before injury or death results.
Identify the three zones of ecological tolerance.
The three zones of ecological tolerance are optimal range, physiological stress, and zone of intolerance.
Optimal Zone
organisms survive, grow, and reproduce
Zone of Physiological Stress
organisms survive, but experience stress: infertility, lack of growth, less activity
Zone of Intolerance
where organisms will die
Provide an example of a physiological stressor or impact an organism could experience in conditions outside of its range of tolerance.
A physiological stressor that can impact an organism is temperature.
At temperatures too high or too low for their tolerance, their activity and health could decrease, but not enough to kill them
Identify THREE examples of natural ecosystem disruptions
Three natural ecosystem disturbances are droughts, hurricanes, and forest fires.
Periodic Events
occur with regular frequency
such as (dry-wet seasons)
Episodic Events
Occasional events with irregular frequency
(such as hurricanes, droughts, and fires)
Random Events
no regular frequency
(such as volcanos, earthquakes, asteroids)
Identify 2-3 reasons that earth’s climate has changed over geological time
- changes in earth’s orbit & tilt
- volcanic emissions
Describe why sea level has varied on earth over time
Rising CO2 levels have cause glacial ice to melt
Describe migration
moving to a new habitat as the result of natural disruptions
Identify 3 reasons that a population would migrate
- rising climates
- lack of food sources
- changing seasons
- environment is changing too fast*
Define adaptation
a new trait that increases in organism’s fitness (ability to survive & reproduce)
Describe how adaptations arise in a population
Adaptations arise when mutations in an individual occur and get passed down to offspring until more/all population has the same trait
Define natural selection
organisms that are better adapted to their environment survive and reproduce
Describe what a selective force is and provide an example
A selective force/pressure is the environmental condition that kills individuals WITHOUT ADAPTATION
e.g predation like hawk
Explain how environmental change can lead to evolution or extinction of a species
Environmental change leads to certain traits becoming adaptations for being advantageous which can lead to species evolving. However, if environmental change is too fast and organisms can’t keep up by adapting, they will die out or emigrate.
Primary Succession
starts from BARE ROCK in an area with no previous soil formation
Secondary Succession
starts from already established soil, where DISTURBANCE cleared out plant life
Describe what a pioneer species is
species that appears first when the ground is bare rock or bare soil
such as moss
Late Successional / Climax Community
appears last after soil is deep and with nutrients (after cycles of death and growth)
large trees, maple & oak
