CHAPTER 2 POPULATION AND COMMUNITY DYNAMICS Flashcards
A group of interacting organisms of the SAME SPECIES living in a particular space
Population
Vary in size and character depending on the limits of space that they occupy
Population
Traits of Population?
- Particular gene flow as a result of inbreeding
- Has a life of its own, it establishes itself, grows, reaches a dynamic equilibrium, and declines
- Has a unique ways of allotting resources (eg. Food, space, mate)
- Able to regulate its own growth
- May have social behavior and cooperate for defense, nesting or hunting
A population can be characterized by its pattern of distribution or dispersion,dispersal, density and age structure.
True
The position or spacing of members of a population relative to their neighbors.
Dispersion
3 patterns of distribution?
Uniform distribution,
Random distribution
Clumped distribution
Occurs when individuals are more or less evenly distributed and happens when there is interspecific competition between individuals
Uniform distribution
Occurs when the presence of one individual does not influence others such as that the position of each individual is independent of the other and happen in a population where there is neither mutual attraction nor repulsion from territoriality
Random distribution
Aggregated, contagious, under dispersed and due to patchiness of environmental resources like food, moisture and habitat
Clumped distribution
Give an example of uniform distribution
Examples
Ø Birds are evenly distributed due to territorial habits
Ø Reptiles defend their exclusive territories
Ø Plants are evenly distributed to minimize competition of nutrients and sunlight
Give an example of random distribution
the randomly distribution of spiders and arthropods
in the forest floor
Give an example of clumped distribution
Examples: flock of birds, herd of cattle, school of fish, bed of flowers
When animal population increases, food resources become scarce resulting to intraspecific competition
Dispersal
Few individuals may evade such unfavorable condition by moving away and seeking better habitats called ?
Population dispersal
• The movement of individuals from a home site or birthplace to a new place
•It has a positive effect on the population as it decreases competition and eases pressure on feeding sites; inbreeding is also reduced
Dispersal
The movement of individuals from one place to another
Migration
The act of moving out from their original palce
Emigration
The movement of coming into or joining a population
Immigration
Migration has direct effect on population growth or
decline depending on the balance between emigration
and immigration
True
This are net increase in population
Greater immigration
This are net decrease in population
Greater emigration
The increase in number of individuals in a particular aggregation
Population growth
What are the three major factors of population growth?
Natality, mortality and survivorship
The growth is also facilitated by external factors like favorable climatic condition, elimination of natural enemies, nutritional quality
True
Indicates production of new individuals per unit time under a particular set of ecological condition
Natality
This is usually expressed in rate (birth rate)
Natality
Example: 600 births in an animal population during a particular year so,600 per year or 50 per month. What is this?
Natality
In human demography (study of human population), it is usually expressed as the number of individuals born per 1,000 individuals per unit time
Crude birth rate
CBR = Number of births
/ Midyear total population x 1,000
Natality
The number of individuals dying per unit of time, caused by unfavorable environmental conditions, by diseases, by predators or by competition
Mortality
This is usually expressed in rate (death rate) – number of dying individuals per 1,000 population per year
Mortality
The percentage of individuals living at various ages in a population
Survivorship
It is a percent of surviving individuals from birth to death of the last individual in a ____ ?
CONSTRUCTED SURVIVORSHIP CURVE
What are the 3 types of survivorship curves?
Type I convex curve
Type II – diagonal curve
Type III concave curve.
____. It occurs in population with high survival rate throughout the life span of the species
and heavy mortality once they reach the point of physiological longevity
Type I convex curve
___ populations with a constant death (mortality) rate
Type II diagonal curve
___ This occurs in population with high mortality rate at early stages of life of the
individuals followed by a relatively low death rate among the survivors
Type llI concave curve
Under such conditions, survivorship is 100% until they
reach their physiological longevity
the biotic potential of a population.
In an _______ the population increases rapidly at faster and faster rates because all the added individuals also produces their young.
EXPONENTIAL GROWTH CURVE
In real world, a LOGISTIC GROWTH CURVE or SIGMOID CURVE is more common
True
_____ has an initial phase as slow population growth corresponding to the establishment of the population
S shaped curve
The last phase reaches a dynamic equilibrium close to or at the level called the ____ of the environment
CARRYING CAPACITY
____ is the maximum level of population that a given habitat
can sustain indefinitely without sacrificing the integrity of the same resource to regenerate
Carrying capacity
If a single bacterium is allowed to grow indefinitely following the exponential growth rate, it can produce a biomass as big as the earth in less than a year. But this does not happen because of environmental resistance
True
_____ environmental factors whose effects vary proportionately to the size of the population (biotic factors).
Density dependent factors
Density-dependent factors
a. Predation
b. Parasitism
c. Dispersal and immigration
d. Intraspecific competition
e. Physiological and psychological stress
_____ affect population regardless of the
number of individuals present (abiotic factors)
Density independent factors
Climatic Factors
a. Rainfall
b. Drought
c. Extreme temperature
d. Photoperiod
Anthropogenic Factors
a. Destruction of habitat
b. Land cultivation
c. Pesticides
d. Persistent toxic substances
By nature, individuals rarely exist as single populations, they
aggregate into a ____
Community
_____ an assemblage of species populations that occur together in space and time
Community
The individual property of the . component populations of a
community?
COLLECTIVE PROPERTY
The property that will emerge in a c o m m u n i t y b e c a u s e o f t h e interactions among its components
EMERGENT PROPERTY
A community is said to be AUTOTROPHIC if it can produce its
own energy needs?
True
A forest is an autotrophic community ?
True
A stream traversing a tropical forest is?
HETEROTROPHIC
It is measured in terms of both Species Richness and Evenness of Distribution of individuals per species
SPECIES DIVERSITY
_____ not limited to diversity of species alone but also
include variety of life forms, ecological functions and genetic
variations
BIODIVERSITY
Dominant species are those that may be numerous, possess the highest amount of biomass, occupy the largest space, or have the greatest influence or control over the activities in the community?
SPECIES DOMINANCE
Capacity of a community to recover from an environmental and anthropogenic disturbances.
PERSISTENCE
Capacity of the community to continue and remain stable even in the presence of some disturbances
RESILIENCE
In _____ vertical stratification is manifested by its
different layers of vegetation that harbors a variety of animal life
terrestrial biomes
In ____ such as lakes and oceans, vertical stratification is determined by light penetration, temperature profile and oxygen profile
aquatic ecosystem
___ the upper layer of water which
receives higher amount of light and Ps > Rn,
______the lower depth where little or no light penetration and Ps < Rn; LIGHT
PHOTIC/EUPHOTIC ZONE
APHOTIC ZONE
____ boundary where light is just sufficient to balance Ps and Rn
COMPENSATION POINT
With respect to temperature, upper depth of water is relatively high in temperature, called _____ while lower layer is relatively cooler called ____
EPILIMNION and HYPOLIMNION
The zone where epilimnion and hypolimnion meet and characterized by abrupt change of temperature ____
THERMOCLINE
____ the upper layer of water which receives higher concentration of oxygen
AEROBIC/OXIC ZONE
___ the lower depth where little or devoid of oxygen
ANAEROBIC/ANOXIC ZONE
• Manifested by a mosaic pattern creating horizontal patchiness that adds the complexity of the environment
• Influence by both environmental and biological factors
• Species are clustered in areas where conditions are favorable, zonation happens when climatic and soil factors retard vegetative growth
Horizontal Stratification
The place where two communities meet is their ____ while the area where the two communities blend is the ____
Edge
Ecotone
The gradual series of change in composition and function
of the community____.
ECOLOGICAL SUCCESSION
____ community develops from a site never before occupied
by life (lahar deposits) as against the succession on
disturbed land
Primary vs. Secondary Succession
____ stages of ecological succession
Sere
- the final stage of the succession
- self-generating, self-regulating
- resilient and persistent
- TRF
CLIMAX COMMUNITY
There are two basic categories of communities:
Terrestrial and aquatic
These two basic types of community contain
eight smaller units known as____
Biomes
____ is a large-scale category containing
many communities of a similar nature, whose
distribution is largely controlled by climate
Biome
Its tundra, grassland, desert, taiga, temperate forest, tropical forest abd these are part of _____ Biomes
Terrestrial Biomes
The _________ biomes occupy the most extreme environments, with little or no moisture and extremes of temperature acting as harsh selective agents on organisms that occupy these areas..
tundra and desert
____ have the fewest numbers of species
due to the stringent environmental conditions.
tundra and desert
_____ occur in regions near the equator. The climate is always warm (between 20° and 25° C) with plenty of rainfall (at least 190 cm/year).
Tropical rain forests
_____ probably the richest biome, both in diversity and
in total biomass.
(tropical) Rain forest
More than half of all terrestrial species live in this biome.
Tropical rain forest
Tropical Rain Forests -usual forest found in the Philippines
True
_____ occurs south of the taiga in eastern North
America, eastern Asia, and much of Europe.
Temperate forest biome
Rainfall is abundant (30-80 inches/year; 75-150 cm) and there is a well- defined growing season of between 140 and 300 days.
Temperate forest
_____ is dominated by shrubs with small but thick
evergreen leaves that are often coated with a thick, waxy cuticle, and with thick underground stems that survive the dry summers and frequent fires. It is also occur in parts of South America, western Australia, central Chile, and around the Mediterranean Sea.
Shrubland biome
Dense shrubland in California, where the summers are hot and very dry, is known as ____
Chaparral
occur in temperate and tropical areas with reduced rainfall (10-30 inches per year) or prolonged dry seasons
Grasslands
____ are almost entirely devoid of trees, and can support large herds of grazing animals.
Grasslands
_____ is a type of grassland biome characterized by scattered trees
Savanna
______ are characterized by dry conditions (usually less than 10 inches per year; 25 cm) and a wide temperature range.
Desserts
Most deserts occur at latitudes of 30o N or S where descending air masses are dry. Some deserts occur in the rain shadow of tall mountain ranges or in coastal areas near cold offshore currents.
True
What are the biomes under terrestrial?
Tropical rain forest
Temperate forest
Shrubland
Grassland
Dessert
Taiga (boreal forest)
Tundra
____ a coniferous forest extending across most of the northern area of northern Eurasia and North America.
Taiga (boreal Forest)
_____ receives between 10 and 40 inches of rain per year and has a short growing season. Winters are cold and short, while summers tend to be cool.
Taiga (boreal Forest)
____ defined as a biome with a subarctic climate and a predominance of coniferous trees. The_____ is characterized by long, cold winters and short, cool summers
Taiga
Subartic climate
This biome receives about 20 cm (8-10 inches) of rainfall annually. Snow melt makes water plentiful during summer months.
Tundra
______ a cold, treeless biome found in the attic and on the tops of mountains
Tundra
What are the biomes under aquatic?
Freshwater
Marine
The ______ contains more dissolved minerals than the freshwater biome.
Marine biome
Over 70% of the Earth’s surface is covered in water, by far the vast majority of that being saltwater.
True
two basic categories to this marine biome:
Benthic and pelagic
The upper 200 meters of the water column is the _____ to which light can penetrate.
Euphoric zone
The ____ is subdivided into two zones: running waters
and standing waters.
Freshwater biome
The upper layers have abundant oxygen, the lowermost layers are oxygen-poor.
True
