(Activities and Discussions on Reproductive Health Bill and

the Environment)

 HUMAN POPULATION INCREASED RAPIDLY OVER THE PAST 500 YEARS

 USE OF TRENDS: • LEADERS : FUTURE TRENDS IN NATION’S

POPULATIONS (AGE STRUCTURES) • HELP ANTICIPATE UPCOMING NEEDS

 THUS: CENSUS NEED TO BE ACCURATE

Average Annual Exponential Growth Rates, Philippines: 2000-2040

Year Growth Rate 2000-2005 2.05 2005-2010 1.95 2010-2015 1.82 2015-2020 1.64 2020-2025 1.46 2025-2030 1.27 2030-2035 1.09 2035-2040 0.92

Projected Total Fertility Rates, by Five-Year Interval, Philippines: 2000-2040 (Medium Assumption)

Year Rate 2000-2005 3.41 2005-2010 3.18 2010-2015 2.96 2015-2020 2.76 2020-2025 2.57 2025-2030 2.39 2030-2035 2.23 2035-2040 2.07

Summary of Projected Population, by Five-Year Interval, Philippines: 2000-2040 (Medium Assumption)

Year Both Sexes Male Female 2000 76,946,500 38,748,500 38,198,000 2005 85,261,000 42,887,300 42,373,700 2010 94,013,200 47,263,600 46,749,600 2015 102,965,300 51,733,400 51,231,900 2020 111,784,600 56,123,600 55,661,000 2025 120,224,500 60,311,700 59,912,800 2030 128,110,000 64,203,600 63,906,400 2035 135,301,100 67,741,300 67,559,800 2040 141,669,900 70,871,100 70,798,800

 RELATIVE PROPORTION OF INDIVIDUALS BELONGING TO DIFFERENT AGE CLASSES IN A POPULATION

 CATEGORIES •  PRE-REPRODUCTIVE •  REPRODUCTIVE •  POST-REPRODUCTIVE

 REPRESENTED BY : AGE PYRAMID

DEPENDING ON ITS AGE STRUCTURE: • PYRAMID  LESS INDUSTRIALIZED  HIGH PRE-REPRODUCTIVE  MAY CONTINUE TO GROW : 2 CHILDREN  HIGH WOMEN ENTERING REPRODUCTIVE THAN

LEAVING

• BULLET  STABLE  SAME NUMBER PER GROUP

  GROWTH RATE •  BIRTHS – DEATHS/POPULATION SIZE •  EXPRESSED AS % •  PEAKED AT 2% IN 1965 •  CURRENT = 1.5% PER YEAR

  ZERO POPULATION GROWTH •  BIRTH = DEATH

  FERTILITY RATE •  NUMBER OF CHILDREN BORN TO EACH WOMAN DURING HER LIFETIME •  CURRENT : AVE OF 3.5 CHILDREN/WOMAN

  REPLACEMENT FERTILITY RATE •  AVERGAE FERTILITY RATE REQUIRED TO ACHIEVE LONG TERM ZERO

POPULATION GROWTH •  2.1 CHILDREN PER WOMAN

 NUMBER OF INDIVIDUAL ORGANISMS THE RESOURCES OF A GIVEN AREA CAN SUPPORT

 THE NUMBER OF PEOPLE THAT CAN BE SUPPORTED IN AN AREA GIVEN: •  ITS PHYSICAL RESOURCES BASE • THE WAY THE RESOURCES ARE USED

 PEOPLE EXCEED THE CARRYING CAPACITY OF AN AREA

 EFFECTS OF OVER POPULATION • REDUCTION IN THE QUALITY OF LIFE • OVEREXPLOITATION OF NATURAL RESOURCES • AIR, WATER AND LAND POLLUTION

 FARM SUBDIVISION AND INTENSIFYING CULTIVATION

 OPENING UP OF NEW LANDS FOR AGRICULTURE

 MIGRATION TO CITIES  EMMIGRATION/IMMIGRATION

 CONDITION OF HAVING INSUFFICIENT RESOURCES OR INCOME

 LACK BASIC HUMAN NEEDS • CLOTHING • SHELTER • FOOD

 POOREST COUNTRIES •  STRUGGLE DAILY FOR

FOOD, SHELTER AND OTHER NECESSITIES

•  SUFFER FROM SEVERE MALNUTRTION, EPIDEMIC DISEASE OUTBREAKS, FAMINE AND WAR

 WEALTHIER COUNTRIES •  THE EFFECTS OF

POVERTY MAY BE THE FOLLOWING:  POOR NUTRITION  MENTAL ILLNESS  DRUG DEPENDENCE  CRIME  HIGH RATES OF DISEASE

  REASON (UNCLEAR) •  LACK ADEQUATE RESOURCES •  UNEVEN DISTRIBUTION OF RESOURCES

  HIGHEST POVERTY INCIDENCE •  SULU, MASBATE, TAWI-TAWI, IFUGAO AND ROMBLON,

SARANGGANI, MT. PROVINCE

  LOWEST POVERTY INCIDENCE •  2ND DISTRICT OF NCR (Mandaluyong, Marikina, Pasig, QC

and San Juan) •  4TH DISTRICT OF NCR (Las Pinas, Makati, Muntinlupa,

Paranaque, Pasay, Pateros and Taguig) •  BULACAN •  1ST DISTRICT OF NCR (Manila) •  BATANES

Open your activity books and submit the worksheet BEFORE

LEAVING CLASS (QUIZ)

  EARLY SUCCESSION SPECIES •  HIGH GROWTH RATE, WIDE DISPERSAL, SMALL, FAST

POPULATION GROWTH

  LATE SUCCESSION SPECIES •  LOWER RATES OF DISPERSAL, SLOWER GROWTH RATE,

LONGER LIVES, LARGER

  PRIMARY SUCCESSSION

  SECONDAY SUCCESSION

  DISTURBANCE •  SMALL SCALE •  LARGE SCALE

  Succession is a directional non-seasonal cumulative change in the types of plant species that occupy a given area through time.

  It involves the processes of colonization, establishment, and extinction which act on the participating plant species.

  Most successions contain a number of stages that can be recognized by the collection of species that dominate at that point in the succession.

  Succession begin when an area is made partially or completely devoid of vegetation because of a disturbance.

  Some common mechanisms of disturbance are fires, wind storms, volcanic eruptions, logging, climate change, severe flooding, disease, and pest infestation.

  Succession stops when species composition changes no longer occur with time, and this community is said to be a climax community.

 The concept of a climax community assumes that the plants colonizing and establishing themselves in a given region can achieve stable equilibrium.

 The idea that succession ends in the development of a climax community has had a long history in the fields of biogeography and ecology.

 One of the earliest proponents of this idea was Frederic Clements who studied succession at the beginning of the 20th century.

 However, beginning in the 1920s scientists began refuting the notion of a climax state.

  By 1950, many scientists began viewing succession as a phenomenon that rarely attains equilibrium.

  The reason why equilibrium is not reached is related to the nature of disturbance.

  Disturbance acts on communities at a variety of spatial and temporal scales.

  Further, the effect of disturbance is not always 100 percent.

  Many disturbances remove only a part of the previous plant community.

  As a result of these new ideas, plant communities are now generally seen as being composed of numerous patches of various size at different stages of successional development.

 Primary succession - is the establishment of plants on land that has not been previously vegetated - Mount Saint Helens. Begins with colonization and establishment of pioneer species.

 Secondary succession - is the invasion of a habitat by plants on land that was previously vegetated. Removal of past vegetation may be caused by natural or human disturbances such as fire, logging, cultivation, or hurricanes.

 Allogenic succession - is caused by a change in environmental conditions which in turn influences the composition of the plant community. Example: the deposition of silt may be causing an allogenic succession from salt marsh to woodland.  The adjacent woodland has followed the salt marsh by invading its landward limit.

 Autogenic succession - is a succession where both the plant community and environment change, and this change is caused by the activities of the plants over time. Mt. St. Helens after the last volcanic eruption.

 Progressive succession - is a succession where the community becomes complex and contains more species and biomass over time.

 Retrogressive succession - is a succession where the community becomes simplistic and contains fewer species and less biomass over time. Some retrogressive successions are allogenic in nature. For example, the introduction of grazing animals result in degenerated rangeland.

Table 9i-1: Comparison of plant, community, and ecosystem characteristics between early and late stages of succession

Attribute Early Stages of Succession Late Stages of Succession Plant Biomass Small Large Plant Longevity Short Long Seed Dispersal Characteristics of Dominant Plants Well dispersed Poorly dispersed Plant Morphology and Physiology Simple Complex Photosynthetic Efficiency of Dominant Plants at Low Light Low High Rate of Soil Nutrient Resource Consumption by Plants Fast Slow Plant Recovery Rate from Resource Limitation Fast Slow Plant Leaf Canopy Structure Multilayered Monolayer Site of Nutrient Storage Litter and Soil Living Biomass and Litter Role of Decomposers in Cycling Nutrients to Plants Minor Great Biogeochemical Cycling Open and Rapid Closed and Slow Rate of Net Primary Productivity High Low Community Site Characteristics Extreme Moderate (Mesic) Importance of Macroenvironment on Plant Success Great Moderate Ecosystem Stability Low High Plant Species Diversity Low High Life-History Type r K Seed Longevity Long Short

 An overview of the mechanisms of succession has been produced by Connell and Slatyer (1977, American Naturalist 111: 1119-1144). Connell and Slatyer propose three models, of which the first (facilitation) is the classical explanation most often invoked in the past, while the other two (tolerance and inhibition) may be equally important but have frequently been overlooked.

 The essential feature of facilitation succession, in contrast with either the tolerance or inhibition models, is that changes in the abiotic environment are imposed by the developing plant community. Thus, the entry and growth of the later species depends on earlier species preparing the ground.

  The tolerance model suggests that a predictable sequence is produced because different species have different strategies for exploiting resources. Later species are able to tolerate lower resource levels due to competition and can grow to maturity in the presence of early species, eventually out competing them.

  The inhibition model applies when all species resist invasions of competitors. Later species gradually accumulate by replacing early individuals when they die. An important distinction between models is the cause of death of the early colonists. In the case of facilitation and tolerance, they are killed in competition for resources, notably light and nutrients. In the case of the inhibition model, however, the early species are killed by very local disturbances caused by extreme physical conditions or the action of predators

 The first stage of succession was characterized by the pioneering colonization of annual plant species on bare ground and nutrient poor soils (Figure 9i-1). These annual species had short lifespans (one growing season), rapid maturity, and produce numerous small easily dispersed seeds. The annuals were then quickly replaced in dominance in the next year by biennial plants and grasses. After about 3 to 4 years, the biennial and grass species gave way to perennial herbs and shrubs. These plants live for many years and have the ability to reproduce several times over their lifespans.

 After about 5 to 15 years, the sites were then colonized by a number of different softwood tree species including loblolly pine (Pinus taeda), shortleaf pine (Pinus echinata), Virginia pine (Pinus virginiana), and sweetgum.

 As the softwoods increased in their numbers and grew in height, they began forming a forest canopy. This canopy reduces the amount of light reaching the forest floor.

 The resulting shaded understory conditions caused the exclusion of many light loving perennial herb and shrub species. Low light conditions also inhibited the germination of pine seedlings.

 Perennial herb and shrub species that were adapted to low light conditions now began to take over the ground cover. The canopy also changed the microclimate of habitat near ground level.

 It was now more humid, has moderated temperatures, and less wind. These conditions, plus the development of a soil litter layer, allowed for the germination of hardwood species, like oak (Quercus spp.) and various species of hickory (Carya spp).

 The seedlings of these tree species also tolerate low light levels.

  By about 50 to 75 years after the initial colonization of the pioneer species, the hardwoods started to replace the softwood species in the developing forest.

  At this stage in the succession, the pines had maximum heights of about 25 meters, while the oaks and hickories were on average about 10 meters tall.

  Because of their shorter lifespans (50 years), many of the softwood species were beginning to die out and the gap that was created was then filled by a subdominant hardwood tree.

  Hardwood species, like oak and hickory, can live for more than 100 years. Sites more than 100 years old were found to be dominated by mature oak forests.

 GROUP OF ORGANISMS (PLANTS/ANIMALS)

 INTERACTING

 INHABITING A GIVEN AREA

 GUILDS

 AUTOTROPHS

 HETEROTROPHS

 DOMINANTS • MOST NUMEROUS • HIGHEST BIOMASS •  PRE-EMPT MOST SPACE •  LARGEST CONTRIBTUION TO ENERGY FLOW •  INFLUENCE OVER THE OTHERS

 RELATIVE ABUNDANCE

 SPECIES DIVERSITY

 SPECIES RICHNESS

 MATERIALS NEEDED: •  10 sheets of newspaper •  Students •  Conflicts inside a raffle box (eg. Typhoons, famine,

disease etc)

 THE GAME •  Newspaper sheets will be placed on the floor so as to

accommodate everybody •  The teacher will pick one conflict from the raffle box

which is equivalent to number of newspaper sheets to be removed

•  Students should do something to let themselves in the sheets or else they will be out of the game

•  Typhoon, Famine, Drought, Floods = 1; Disease = 2

1.  What is the connection to the environment?

2.  2. What is the connection to the population in urban areas?