Ecology Quiz 3 Flashcards
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What is a population?
All the individuals of one species who are living close enough together to interact with one another
What is a population characterized by? (2 main, 4 minor_
2 Main: #of individuals & Density
- Age distribution, growth rates, distribution, abundance
Physical environment____ geographic distribution of species
limits
What do you suppose is the major factor in the distribution of Kangaroos?
climate
What are 4 other factors that also limit Kangaroo distribution other than climate?
- Food production
- Water supply
- Habitat
- Incidence of parasites, pathogens, and competitors
In lower latitudes, tiger beetles probably live at__ elevations
High
Encelia species distribution corresponds to___&___
temperature and precipitation
Chthamalus stellatus (barnacles) are restricted to\_\_\_ why?
They are restricted to upper levels of inter-tidal zone because Chthamalus adults are excluded from lower levels of inter-tidal zone by competition
Balanus balanoides (barnacles) are limited to____ why?
They are limited to mid & low levels of inter-tidal zones because they are vulnerable to desiccation, excluded from upper inter-tidal zone
What are the 3 distributions of individuals discussed?
Random, regular, clumped
Describe random distribution of individuals?
Equal chance of being anywhere
Describe what causes random distribution of individuals and the processes of the individuals?
- Uniform distribution of resources
- Processes: Neutral interactions between individuals. Neutral interactions between individuals and local environment
Describe regular distribution of individuals?
Uniformly spaced
Describe what causes regular distribution of individuals & processes?
-Exclusive use of area
-Individuals avoid one another
Processes: Antagonistic interactions between individuals or local depletion of resources
Describe clumped distribution of individuals
- unequal chance of being anywhere
- Individuals live in areas of high local abundance, which are separated by areas of low abundance
Describe what leads to clumped distribution of individuals and processes
-mutual attraction between individuals
-Patchy resource distribution
Processes: Attraction between individuals or attraction of individuals to a common resource
Which is not a major distribution pattern for individuals in a population?
-Scattered
Aggressive bee colonies should be—-
Uniform
Non-aggressive bee colonies should be—
Random and/or clumped
Why are young shrubs clumped? (3 reasons)
- Seed germinate at safe sites
- Seeds not dispersed from parent areas
- Asexual reproduction
What were the reasons why shrub plants distribution changes over time as stated by Phillips and Macmahon?
- As plants grow, some individuals in clumps die, reducing the clumping
- Competition among remaining plants -> higher mortality
- Eventually -> regular distributions
Describe large scale distributions of bird populations across N.A.
- bird populations - clumped distributions in Christmas Bird counts
- Clumped patterns in species with wide spread distributions
How does animal body size relate to population density?
Smaller animals have denser populations
Plant population density ___ with ____ in plant size
Plant population density DECREASES with INCREASE in plant size
Describe population density trends of trees?
- Tree seedlings can live at very high densities
- As trees grow, density declines until mature trees are at low densities
Rabinowits “commonness” classification is based on what 3 factors?
- Geographic range of species
- Habitat tolerance
- Local population size
For a species least threatened by extinction geographic rang is__
extensive
For a species least threatened by extinction, the habitat tolerance is __
broad
For a species least threatened by extinction, local populations are ___
often large
Describe an organism classified as Rarity 1
-Extensive Range
-Broad habitat tolerance
-Small local populations
Ex: Peregrine Falcon
Describe an organism classified as Rarity 2
-Extensive Range
-Large populations
-Narrow habitat tolerances
Ex: Passenger pigeon
Describe an organisms classified as Rarity 3
-Restricted range
-Narrow habitat tolerance
-Small populations
Ex: California Condor
What is dispersal?
The permanent movement of an individual
What is Holling?
- Numerical response to increased prey availability
- Increased prey density -> increased predator density
- Movement of predators
Imagine aquat insect larvae, live larval damselflies and dragonflies, what direction do you think they tend to move?
-Downstream
What are 3 adaptions for maintaining position of stream dwellers?
- Streamlined
- Bottom-dwelling
- Adhesion to surface
Describe the upstream & downstream movement involved in the colonization cycle?
Drift moves organisms downstream, sometimes actively as behavioral drift, sometimes passively with floods
-Many organisms engage in upstream movements that appear to compensate for downstream drift
What do patterns of survival tell us?
-when individuals usually die
What are the 3 methods of estimating patterns of survival
- Cohort life table
- Static life table
- Age distirbution
Explain the assumption made by Dall sheep skulls?
Assumption: Proportion of skulls in each age class represented typically proportion of individuals dying at that age
What method does the Dall sheep skull describe?
Static life table
Age distributions are useful in:
-predicting the likelihood of future population growth
understanding the impact of past events
-understanding reproductive patterns
Age distribution of a population___
reflects history of survival and reproduction, plus growth potential
____birth rates by age class
Fecundity schedule
When generations do not overlap, leads to ___
geometric growth
What is a good example of an organism whose populations show continuous growth, with overlap between generations?
Elephants
Continuous population growth in an unlimited environment can be modeled___
exponentially
What probably caused the slow growth rates of collared doves?
- not enough food for continued growth
- not enough nesting sites
Logistic population growth, resources depleted ->
population growth slows and stops
Logistic population growth curve is___
Sigmoid S-shaped
What is K on a graph of population growth?
Carrying capacity
-Finite resources -> finite # individuals
