Ecology Exam 2.2
Cruise Searcher
Searches over large distance in short time (vultures/hawks).
Saltatory Searcher
Moderate search disance with pauses in search (American Robin).
Ambush Searcher
Long waiting period and small search distance.
Evolutionary Arms Race
Predator and prey continually evolve to gain advantages over eachother.
Fleeing
Most effective against cruiser search strategy (impala).
Hiding
Most effective against cruiser/saltatory search strategy (helmeted iguana).
Size
Most effective against ambush search strategy (elephants).
Species Reintroduction
Wolves reintroduced to Greater Yellowstone ecosystem to check herbivore population.
Ocean Exploitations
Fur seals (1700-1800s), cod (early 1900s), whales (mid-1900s), krill (today).
Tragedy of the Commons
Public resources will be exploited faster than they can be replaced.
Maximized Sustainable Yield
Harvesting at a replacement rate to sustain population.
Prudent Predation
Predator strategies are not 100% effective, some prey are allowed to escape. Prey strategies are not 100%, some prey are allowed to be captured.
Repoductively Based Social Organization
Male-female or parent-offspring.
Resource Based Social Organization
Territoriality or dominance hierarchies. Involve aggressive/agonistic behaviors.
Types of Groups
Social groups (intrinsically social at all times) and aggregations (temporary association in response to resource abundance).
Fitness
The genetic contribution of an individual’s descendants to future generations of a population.
Inclusive Fitness
Individuals fitness + fitness of relatives, weighted by degree of relatedness.
Kin Selection
Differential reproduction among lineages of closely related individuals.
Altruism
Organism incurs a cost in fitness in order to benefit a recipient (occurs most frequently between relatives).
Reciprocal Altruism
Altruistic behavior with expectation of future repayment.
Spitefulness
Actor and recipient are both impacted negatively.
Cooperation
Both actor and recipient benefit.
Selfishness
Actor benefits at the cost of recipient.
Territoriality
Any defended area (Nobel 1939).
Theory of Economic Defense
Area defended if benefit to reproductive fitness outweighs energy costs (Brown 1964).
Cost of Territoriality
Based on resource dispersion, number of intruders, number of neighbors, and familiarity of neighbors.
Dominance Hierarchy (Pecking Order)
Develops when resources are not defendable; dominant organism gets exclusive resource use (maintained with agonistic behaviors).
Dominance
Based on size, strength, age (experience), luck, and coloration.
Social Organization Plasticity
Organisms can switch between territoriality and dominance hierarchy (sheepshead minnow).
Benefits of Grouping
Faster location of resources, greater protection from predators.
Group Protection from Predators
Heightened vigilance for predators, dilution effect, “selfish herd” effect (Hamilton), and group defense (zebra).
Eusociality
Development of castes (hymenoptera/naked mole rats).
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