Ecology Flashcards
What is ecology
The study of how organisms interact with each other and the environment
What is geographic distribution
Where organisms are found
What is geographic abundance
How many organisms are found in a given area
What are patterns of distribution on a global scale
Physical and climatic barriers prevent dispersal of individuals from birth home to new geographic distributions
What us an example of a physical barrier disperal
Giraffes separated by continents
What is an example of a climatic barrier to dispersal
Snakes have no freeze tolerance and therefore can’t survive in higher latitudes
How is distribution and abundance affected by abiotic factors
- Temperature
- Light intensity
- Water availability
- Terrain
What is abiotic
Non-living
How does tolerance affect an organisms survival rate from abiotic factors
Organisms can survive in an area over a long period of time only if abiotic conditions are withing the organisms range of tolerance
How is distribution and abundance affected by biotic factors
- The presence/absence of other organisms
- Tree coverage
- Food requirements
- Predators
- Competitors
What is biotic
Living
What is an example of abiotic and biotic factors on a local distribution of intertidal organisms
Barnacles and muscles are marine animals and do better in the water than when exposed to air. Length of time an intertidal organism is exposed to terrestrial conditions depend upon its location in the intertidal zone
What are abiotic conditions in the intertidal zone
More optimal for intertidal organisms when exposed to marine conditions. Stressful when exposed to air. Ex: organisms closer to tide are more likely to survive than organisms further from tide
What are biotic conditions in the intertidal zone
Predation intensity from marine predators is higher when intertidal organisms are submerged in water. Competition for limited resources like space is more intense in locations where abiotic conditions are more optimal
What is population
A group of individuals of the same species that live in the same area at the same time
What is population ecology
How population size changes with time and location
What is population size
Total number of individuals in a population
What is population density
Number of individuals per unit area
What is the main reason for population decline
Habitat loss
How do biologists estimate population size
Estimate abundance through sampling
What are the techniques to estimate population size
- organisms that move = mark recapture technique
- organisms that don’t move = quadrat sampling
What is the mark recapture technique
Visit 1: capture individuals, count and mark, release
Visit 2: capture individuals (some will be marked, some won’t), count marked and unmarked
What is the Lincoln-Peterson method for mark and recapture
Assumes proportion of marked/total in second visit sample is representative of the proportion of marked/total population
What is the equation for the mark and recapture technique
Estimated population size (Ň) = Marked individuals (M) multiplied with total number of individuals caught in second sample (n) divided by marked individuals caught in the second sample (m)
What are the assumptions of the Lincoln-Perterson method
- Population is closed: no births, deaths, movement of individuals in/out
- Individuals don’t differ in their probability of being caught: marking doesn’t affect probability of being caught
- Individuals don’t lose marks between sampling methods
When population size varies with change, what factors cause it to change?
- Birth: increase
- Death: decease
- Immigration: increase
- Emigration: decrease
