Chapter 8 Flashcards
is a group of individuals of the same species that inhabit a given area
population
have unique features because they are an aggregate of individuals
population
two important features of population
- Genetic unit
- spatial concept
Three types of lateral modular growth in plants that produce ramets:
stolons
rhizomes
suckers
specialized stems that grow above the surface of the substrate
Stolons
specialized stems that grow below the surface of the substrate
Rhizomes
new stems from the surface roots
Suckers
two levels of population structure:
genet
ramet
a genetic individual produced by (a plant’s) sexual reproduction, thus arising from a zygote
genet
modules produced asexually by the genet; can produce seeds (through sexual reproduction) and their own lateral extensions or ramets (asexual reproduction)
Ramets
group of genetically identical modules, or ramets, that are produced asexually by the genet
Clonal colony
Population STRUCTURE
- Distribution
- Density
- Proportion of age classes
Population DYNAMICS
- Birth
- Death
- Migration
based on the presence and absence of individuals which defines the spatial extent of a population
Distribution
defined area that encompasses all the individuals of a species
Geographic range
the place or environment where an organism lives
habitat
Factors influencing the population distribution
habitat suitability
geographic barriers
a species with a geographically widespread distribution
Ubiquitous
a species with a distribution that is restricted to a particular locality or localized habitat
Endemic
a collective of local populations linked by the dispersal of individuals; due to environmental heterogeneity, most populations are divided into subpopulations, each occupying suitable habitats
metapopulation
geographic barriers
- mountain ranges
- interactions, such as competition and predation, with other species
the total number of individuals in the population
Abundance
two factors of abundance
population density
the area which the population is distributed
density that is measured simply as the number of individuals per unit area
crude density
Patterns of the spatial distribution for individuals within a population:
random
regular
clumped
if each individual’s position is independent of those of the others
random
an individual has an equal probability of occurring anywhere in an area
random
neutral interactions between individuals and local environment
random
more or less evenly spaced; usually results from some form of negative interaction among individuals, such as competition, which functions to maintain some minimum distance among members of the population
regular
Individuals are uniformly spaced through the environment
regular
antagonistic interaction between individuals or local depletion of sources
regular
most common spatial distribution in which individuals occur in groups
clumped
individuals live in areas of high local abundance, separated by areas of low abundance
clumped
which is the number of individuals per unit of available living space; to account for patchiness
ecological density
attraction between individuals or attraction of individuals to a common resource
clumped
Sampling methods
quadrat method
mark-recapture
Lincoln-Petersen index
indices of abundance
method of sampling used widely in the study of populations of plants and sessile (attached) animals
quadrat method
the most widely used technique for mobile animals to estimate animal populations which involves capturing, marking, and recapturing individuals within a population
mark-recapture
the simplest single mark–single recapture method
Lincoln–Petersen index
a measure of relative density or abundance that cannot function alone as estimates of actual density
indices of abundance
indices of abundance examples
vocalization
heard, recording of calls
counts of animal scats
animal tracks
do not tell us anything; measurement of population structure includes age, developmental stage, and size
abundance
the number or proportion of individuals in different age classes
age structure
a product of the age-specific patterns of mortality and reproduction
age structure
restricted to certain age classes
reproduction
three ecologically important age classes or stages
- prereproductive
- reproductive
- postreproductive
by counting annual growth rings approximate ages of trees in which growth is seasonal can be determined
dendrochronology
snapshots of the age structure of a population at some period in time, providing a picture of the relative sizes of different age groups in the population
Age pyramids
protandry
male first to female later
protogyny
female first to male later
reasons of dispersal
crowding
temperature change
quality and abundance of food
photoperiod
Which sex is dominant in mammals? Why?
Males often have higher mortality rates due to competition, aggression, or predation, leading to a higher female ratio in older age groups.
Which sex have higher mortality rate in birds?
Females have higher mortality rate due to being susceptible to predation and attack when nesting
movement of individuals in space
dispersal
Unintentional dispersal examples
- Long distance dispersal by humans: PRIMARY CONCERN
- Snakes in Apo Island
- Ballast water and soil in cargo ships
- Transport of cargoes (logs, sediments, etc.,)
- Ornamental plants
when individuals move out of a subpopulation
emigration
when an individual moves from another location into a subpopulation
immigration
round trip movement of animals; return trips may be daily or seasonal
migration
a reproductive strategy wherein an organism reproduce once then dies
semelparous
a reproductive strategy wherein an organism reproduce repetitively
iteroparous
a new source of long-distance dispersal that has led to the redistribution of species at a global scale
dispersal by humans
