BIO 319 Exam #2 Questions and Answers
What is a Population?
A group of individuals of the same species that is spatially distinct from other groups of individuals of
the same species.
Density (Calculation)
Density (#/area) = # of individuals (population size)/area
On a 20-hectare island there are 2,500 lizards. What is the population density?
2500/20 = 125 hectare^-1
Absolute population size
Populations actual abundance
Relative population size
# of individuals in one time period or place relative to the number in another
ex. # of cougar tracks in a given area
Area-based count
- usually for immobile organisms
Quadrats--> Sampling areas of specific size such as 1m^2
- individuals are counted in several quadrats and averaged to estimate population size
,Distance methods
line transects- observer travels along line and counts individuals and their distance from the line
Mark- recapture studies
- used for mobile organism
- subset of individuals are captured, marked/tagged then released
- at a later date, individuals are captured again, and the ratio of marked to unmarked individuals is
used to estimate population size
Mark- recapture studies (equation)
M/n = m/n
or
N = (M)(n)/m
N = estimate of total population size
M = original number captured and marked
n = number recaptured
m = number of recaptured that are marked
23 butterflies are captured and marked. After 24 hours, 15 butterflies are captured and 4 of them
are marked.Estimate total population size:
(23)(15)/4 = 86.25 butterflies
An organisms life history
a record of events relating to its growth, development, reproduction and survival
Life history characteristics
, - Age and size at sexual maturity
- Amount and timing of reproduction
- Survival and mortality rates
What do differences in life history arise from?
Genetic Variation and Environmental Variability
What does natural selection favor?
Individuals whose life history traits result in a better chance of surviving and reproducing.
How does natural selection relate to fitness?
Natural selection favors individuals with traits that maximize fitness, which is the genetic
contribution to future generations.
Metamorphosis
Abrupt transition in form between the larval and juvenile stages
2 Stages: different body forms, different habitats, different food
Phenotypic plasticity
The ability of a single genotype to produce different phenotypes under different environmental
conditions.
Ex. a pine tree roots and leaves in warm dry climate vs cool moist climate
Morphs
What is a Population?
A group of individuals of the same species that is spatially distinct from other groups of individuals of
the same species.
Density (Calculation)
Density (#/area) = # of individuals (population size)/area
On a 20-hectare island there are 2,500 lizards. What is the population density?
2500/20 = 125 hectare^-1
Absolute population size
Populations actual abundance
Relative population size
# of individuals in one time period or place relative to the number in another
ex. # of cougar tracks in a given area
Area-based count
- usually for immobile organisms
Quadrats--> Sampling areas of specific size such as 1m^2
- individuals are counted in several quadrats and averaged to estimate population size
,Distance methods
line transects- observer travels along line and counts individuals and their distance from the line
Mark- recapture studies
- used for mobile organism
- subset of individuals are captured, marked/tagged then released
- at a later date, individuals are captured again, and the ratio of marked to unmarked individuals is
used to estimate population size
Mark- recapture studies (equation)
M/n = m/n
or
N = (M)(n)/m
N = estimate of total population size
M = original number captured and marked
n = number recaptured
m = number of recaptured that are marked
23 butterflies are captured and marked. After 24 hours, 15 butterflies are captured and 4 of them
are marked.Estimate total population size:
(23)(15)/4 = 86.25 butterflies
An organisms life history
a record of events relating to its growth, development, reproduction and survival
Life history characteristics
, - Age and size at sexual maturity
- Amount and timing of reproduction
- Survival and mortality rates
What do differences in life history arise from?
Genetic Variation and Environmental Variability
What does natural selection favor?
Individuals whose life history traits result in a better chance of surviving and reproducing.
How does natural selection relate to fitness?
Natural selection favors individuals with traits that maximize fitness, which is the genetic
contribution to future generations.
Metamorphosis
Abrupt transition in form between the larval and juvenile stages
2 Stages: different body forms, different habitats, different food
Phenotypic plasticity
The ability of a single genotype to produce different phenotypes under different environmental
conditions.
Ex. a pine tree roots and leaves in warm dry climate vs cool moist climate
Morphs
