73 terms

Ch. 54


Terms in this set (...)

What is the defining feature of exponential growth?
A. the population is growing very quickly
B. the growth rate is constant
C. the growth rate increases rapidly over time
D. the growth rate is very high
List four features that define population growth.
Birth death immigration and emigration
In what populations does exponential growth tend to occur?
A. populations that colonize new habitats
B. populations that experience intense competition
C. populations that experience high rates of predation
D. populate that have surpassed their carrying capacity
True or false? Climate change can influence the population growth of species
If most individuals in a population are young , why is the population likely to grow rapidly in the future?
A. death rates will be low
B. the population has a skewed age distribution
C. immigration and emigration can be ignored
D. many individuals will begin to reproduce soon
Why have population biologists become particularly interested in the dynamics of metapopulations?
A. because humans exist as a metapopulation
B. because whooping cranes exist as a metapopulation
C. because many populations are becoming restricted to small islands of habitats
D. because metapipulations explain why populations occupying large, contiguous areas are vulnerable to extinction
describe the life history traits of elephants
A. high survivorship, high fecundity
B. low survivorship, high fecundity
C. high survivorship, low fecundity
D. low survivorship, low fecundity
Offer a hypothesis to explain why humans has undergone nearexponential growth for over 500 years. Why can't exponential growth continue indefinitely? describe two example of density dependent factors that my influence human population growth
The population has undergone near exponential growth recently because advances in nutrition, sanitation, and medicine have allowed humans to live at high density without suffering from decreased survivorship and fecundity. Eventually, however, growth rates must slow as density dependent defects such as disease and famine increase death rates and lower birth rates.
Explain why biologists want to maintain
A.) habitat corridors that connect populations in a metapopulation
B. unoccupied habitat that is appropriate for the species in question
A. corridors allow individuals to move between populations, increasing gene flow and making it possible to recolonize habitats where populations have been lost.
B. maintaining unoccupied habitats make it possible for habitat to be recolonized
Ranges are dynamic in constant flux as __ and ___ change over time
Abiotic and biotic
Population density
The number of individuals in an area
A population of populations connected by migration
More species are being forced into a
metapopulation structure
Number of individuals in a population depends on
Birth, death, immigration, and emigration
Population increase
Population decrease
The study of factors that determine the size and structure of populations through time
Age structure
How many individuals of each age are alive
Life table
Summaries the probability that an individual will survive and reproduce in any give time interval of time course of its lifetime
Scientists focus on _____ when calculating life table data
Age class
Is a group of individuals of a specific age
A group of the same age that can be followed through time
The proportioning of offspring produced that survive on average to a particular age
Number of female offspring produced by each female in the population
Net reproductive rate
Indicates whether a population is increasing or decreasing
Fitness trade offs occurs because
Every individual has a restricted amount of time and energy as its disposal
Resources are limited
Life history
Describes how an individual allocate resources to growth, reproduction, activities, or structures that are related to survive
Life history is shaped by natural selection in
A way that maximizes an individuals fitness in its environment
Individuals from species with high fecundity
Grow quickly
Reach sexual maturity at a young age
Produce many small eggs or seeds
Individuals from species with high survivorship
Grow slowly
Invest resources in traits that reduce damage from enemies
Increase their own ability to compete for water, food, sunlight
Per capita rate of increase
-difference between death rate and birth rate per individual
r +=
r - =
Intrinsic rate of increase
Rmax; optimal conditions for a species is reached, r reaches a max valve
Intrinsic rate of increase equation
Change N/Change t =rmax
Exponential population growth
When r does NOT change over time
Growth rate does not depend on the number of individual in the population
Density dependent
Growth rate does not depend on the number of individuals in a population
Exponential growth is common if
A few individual found a new population in a new habitat
A population has been debated by a storm or some other type of catastrophe and then begins to recover
Carrying capacity depends on
Resting and nesting sites
Soil quality
logistic growth equation
Change N/Change t =rmax N [K-N]/K
logistic growth
Changes in growth rate that occurs as a function of population size
Density dependent
Density independent factors
Alters birth and death rates
Abiotic environment factors
-weather patterns
-catastrophic events
Density dependent factors
Change in intensity as a function of populating size
Biotic factors
Population dynamics
Changes in population through time and space
Each population within the larger metapopulation is expected to go
Migration from nearby population can
Reestablish population in empty habitat fragments
Analyzing an age pyramid can give biologists
Important information about a populations history but also help researchers predict a populations future
Replacement rate
Is the average fertility required for each women to produce exactly enough offspring to replace herself and her offspring fathers
Zero population growth
r=o fertility rate is sustained for a generation
When designing programs to save species threatened with extinction conservation biologists draw heavily on concepts and techniques from
Population ecology
Four attributes of population that are most likely to persist
-they have larger population size
-they occupy larger geographical ranges
-they are closer to neighboring populations (more likely to colonize)
-the have higher genetic diversity
Estimated population
M-# of marked individuals in the 1st sample
C-# of individuals captured total in 2nd sample
R-# of recaptured individuals (marked)
Dispersion patterns
Organisms in patches, unequal distribution to resources, predation response, prey together
Equally spaced
Social behavior territorial, trends need space because of roots
No predictable pattern
rare in nature
Short term
How would the dispersion patterns affect the sampling of individuals
Clumped: hit or miss
Uniform: easiest sampling
Random: difficulty mating
Spatial scale
Know enough about the organisms to know the scale to use
Key tools used for demography
Life table
Survivorship curve
Life history
life table
Data in a table
Shows survivorship and fecundity
Get age structure or population
Survivorship curve
3 types
Life history
How organisms allocates resources to growth reproduction and survival activities
Humans are what type of survivorship curve
Type 1
Population growth rate equation
r= ΔN/ Δt
Two mathematical models
Exponential growth
logistic growth
Exponential growth equation
ΔN/ Δt= (B+I)-(D+E)
Exponential growth equation per capita
ΔN/ Δt=rN
Exponential growth
Rare short lived
Unlimited resources available
r is density independent
Unlimited environment
Resources: food, water, space, shelter, refuge, mating, breeding, nesting
Logistic growth equation
Logistic growth
Common in nature
Limited environment
Growth rate density dependent
k= carrying capacity
Carrying capacity
# of individuals that can be supported in that particular environment and of that particular time
-limited resources
Variable through
What limits growth rate and population size
Population dynamics
Change through time