Ch. 53: Population Ecology Flashcards
Predict the distribution pattern for male bearded dragons who actively defend territory.
uniform
because they are territorial
Would you expect an r or k species to exhibit a Type III survivorship curve? Why or Why not?
Type III: density dependent: most die at an early age (L)
r- species: density - independent
k- species: density - dependent
expect k species to exhibit Type III survivorship
Why are natural populations’ growth trajectories better modeled using logistic rather than exponential growth?
Logistical model is more realistic
- shows there is a limited number of resources
- carrying capacity
What determines the carrying capacity for a population?
number of people or animals in a population
number of resources
carrying capacity: limit to how many organisms can survive in a certain population
Has the Earth reached the carrying capacity for humans? Defend your answer.
- have seen a slower population growth
- means either quickly approaching the carrying capacity or have overshot
- with this economy, it is most likely that we have overshot and have reached carrying capacity
Provide 6 examples of density-dependent regulation.
1) Competition for resources
2) Predation
3) Disease/Pathogens
4) Territoriality: more space required, few places for others to live
5) Intrinsic factors: hormones; mechanics within organism you are looking at
6) Toxic wastes
Biological processes influence
population density, dispersion, and demographics
The exponential model describes
population growth in an idealized, unlimited environment
The logistic moder describes
how a population grows more slowly as it nears its carrying capacity
Life history traits are
products of natural selection
Many factors that regulate population growth are
density dependent
The human population is…
no longer growing exponentially but is still increasing rapidly
3 patterns of dispersion
1) Clumped
2) Uniform
3) Random
Clumped
Starfish
water source, food, sunlight
Uniform
equal distance (rare in nature) - territoriality, aggression
- Penguins
Random
doesn’t seem like any pattern
trees, wind dispersion
carrying capacity
limit to how many organisms can survive in a certain population
Overshoot
temporary defiance of carrying capacity
- generally associated with temporary increase in resources
r-selection
density independent
- make as many offspring as possible
- low parental investment
- high mortality @ early age
i.e. dandelions, shrimp, nematodes, spiders
k-selection
density dependent
- make fewer offspring
- parental investment high
- low mortality @ early age
i.e. humans, whales
Ecology
the study of organisms in relation to their environment
Abiotic Factor
physical, nonbiological
i.e. light, temperature, moisture (water, humidity, rain/snow), chemicals (nutrients, toxic, etc)
Biotic Factors
other living things
i.e. predators, prey, parasite, competitors, benefactors, mates
Population
group of individuals of the same species with potential for interaction
- same place @ same time
Cohort
group of individuals that are studied together
Life Table
an age-specific summary of the survival pattern of a population
3 types
Type I
relatively low death rates in earlier years, but higher at older age
-parental care, more competition, density dependent ( 7 )
i.e. humans
Type II
same death rate throughout life ( \ )
Type III
Density independent ( L )
most die at early age
i.e. insects, shrimp
Demography
the study of changes over time in the vital statistics of populations, especially birth rates and death rates
