THE EFFECT OF HUMAN POPULATION DENSITY ON THE ENVIRONMENT

BASIC COMPETANCE

7.3. to predict the effect of human population density on the environment

INDICATORS

7.3.1. to estimate the relationship between human population density and needs of clean water

7.3.2. to estimate the relationship between human population density and needs of food

7.3.3. to estimate the relationship between human population density and area available

7.3.4. to explain the influence of human population increase on the environmental damage

THE INFLUENCE OF POPULATION DENSITY ON THE ENVIRONMENT

The population change influenced by:

1.      BIRTH RATE

2.      DEATH RATE

3.      MIGRATION

Birth rate is the number of alive baby born per one thousand the number of population per year. The formula of birth rate is:

B.R. = ∑ alive baby born       x 1000             ∑ of population

Criteria of birth rate are:

1. B.R. is high if greater than 30
2. B.R. is medium if 20 – 30
3. B.R. is low if less than 20

Example

The number of population of Semarang city on 2006 is 500.000 people. While the number of alive baby born on it’s year is 20.000 people. So the birth rate of Semarang city is:

B.R. = 20.000       X 1000

           500.000

        = 40

Based on the counting of B.R. above, we know that the criteria of B.R. of Semarang city is high because B.R. greater than 30.

Death Rate is the number of people death per one thousand per year. D.R. can be count by the following formula:

D.R. = ∑ of death people      x  1000             ∑ of population

Criteria of death rate are:

1. D.R. is high if greater than 18
2. D.R. is medium if 14-18
3. D.R. is low if  less than 14

Example

The number of people of Semarang on 2004 is 5000 people, while the number of death people is 25, so the death rate of Semarang is:

D.R. =     25         X 1000

                5000

        =      5

So death rate of Semarang on 2004 is 5, it’s mean per one thousand of people there are 5 people has die. Based on the criteria, death rate of Semarang is low because less than 14.

The population change rate can be count by formula:

C.R.   =  B.R. -   D.R.          x 100                    1000

A population increases if birth rate is greater than the death rate. While a population decreases if the birth rate is less than the death rate. When the birth rate equal to death rate, the population will stay the same size.

The population density is the number of people that live in the certain area with the certain wide.

The formula of population density is:

P.D.   =   ∑ of people               Wide of area

Example:

On 2006, Demak with 50.000 km² wide have 500.000 people, so the population density of Demak is:

P.D.  =    500.000 people

                50.000 km²

         =     10 people/km²

The influenced of the population density are:

1. problem of providing food

when the population change rate is greater than the increase    food production, it can make decrease of people prosperity, this can make lack of food.

2. decrease of clean water
3. decrease of the number of forest / deforestation to make new houses or had been converted into farmlands.
4. increase of waste on the environment, it’s condition make unhealthy sanitation.
5. increase of infectious disease, so the people get sick easily.
6. increase of pollution in the environment
7. because of the increasing of population growth, it makes many area such as forest, park, green zone become smaller and smaller, because they build houses, the main roads or factories, so only small amount of   water can be absorbed into the soil
   ACTIVITY 7.1
   
   
   DESIGNING A SIMPLE TOOL
   How to provide clean water
   Objective: To know provide clean water
   
   
   What would you do to get clean water if there is only limited stock available in you surrounding? To answer the question, do the following activities.
   
   
   Tool and material 
   2 plastic bottles of 2 liter volume 
   big pebbles 
   small pebbles 
   palm leaf rib 
   sands 
   cotton 
   water which will be filtered 
   a knife or scissors

Procedure

1. Cut the bottles into two parts, the top part is used as a filter and the bottom part is used for the filtered water.
2. Put the provided materials into filter 1 to produce clean water as it is designed. Then fill up the bottom part of bottle with water that will be filtered.
3. Create a second design for bottle 2.
4. Compare the results of design 1 with that of design 2.

Problem:

1. How is the water condition before being filtered in both samples?

…………………………………………………………………………….

…………………………………………………………………………….

2. Which design produces the cleanest water? Why?

…………………………………………………………………………….

…………………………………………………………………………….

Conclusion:

Write your conclusion based on your experiment!

KINGDOM ANIMALIA

Classification of animals is based on type of symmetry, number of tissue layers, type of coelom, and presence of segmentation.

Generally characteristics of Kingdom Animalia:

            Multicelluar organisms with well-developed tissues; ussually motile; heterotrophic by ingestion, generally in digestive cavity; diplontic life cycle. Protostomes include phyla Mollusca, Annelida, and Arthropoda. Deuterostomes include phyla Echinodermata, Hemichordata, and Chordata.

INVERTEBRATES

            Phylum Porifera : sponges

            Phylum Cnidaria: jellyfish, sea anemones, corals

            Phylum Ctenophora: comb jellyes, sea walnuts

            Phylum Platyhelminthes: flatworma, e.g., planaria, flukes, tapeworms

            Phylum Nemertea: ribbon worms

            Phylum Nematoda: roundworms

            Phylum Rotifera: rotifers

            Phylum Mollusca: chitons, snails, slugs, clams, mussels, squids, octopuses

            Phylum Annelida: segmented worm,e.g., clam worms, eartworms, leeches.

            Phylum Onychopora: walking worm

            Phylum Arthropoda: spiders, scorpions, horseshoe crabs, lobsters, crayfish,

                                                 shrimps, crabs, millipedes, centipedes, insects

            Phylum Echinodermata: sea lilies,sea stars, brittle stars, sea urchins, sand

                                                       dollars, sea cucumbers, se daisies

            Phylum Hemichordata: acorn worm

            Phylum Chordata:

                        Sub phylum Urochordata

                        Sub phylum Chephalochordata

VERTEBRATES

    Sub phylum Vertebrata

            Superclass Agnatha: jawless fishes, e.g. lampreys, hagsfishes

            Superclass Gnathostomata: jawed fishes, all tetrapods

            Class Chondroicthyes: cartilaginous fishes e.g., shark,

                                                                                        skates, rays

            Class Osteichtyes: bony fishes,e.g., herring, salmon, cod,

                                                                                eel,flounder

            Class Amphibia: frogs, toads, salamanders

            Class Reptilia: snakes, lizards, turtles

            Class Aves: birds, e.g., sparrows, penguins, ostriches

            Class Mammalia: e.g., cats, dogs, horses, rats, humans

KINGDOM PLANTAE

Plants are adapted to living on land. In general, they tend to have features that allow them to live and reproduce on land.

Multi celllular, primilly terrestrial eukaryotes with well-developed tissues; autotrophic by photosynthesis; alternation of generations life cycle. Like green algae, plants contain chlorophylls a and b and carotenoids; store starch in chloroplast; cell wall contains cellulose.

NONVASCULAR PLANTS

Division Hepatophyta: liverwort, example: Marchantia polymorpa

Division Bryophyta: mosses, example: Spaghnum sp

Division Anthocerophyta: hornwort, example: Antherocephala sp.

SEEDLESS VASCULAR PLANTS

Division Psilotophyta:whisk ferns, example: Psilotum nudum

Division Lycopodophyta: club mosses, Lycopodium clavatum, L. ceernum

Division Equisetophyta: horsetails, example: Equisetum debile

Division Pteridophyta: ferns, example: Marsilea crenata, Azola pinnata

SEED VASCULAR PLANTS

            Gymnosperms

            Division Pinophyta: conifers, example: Pinus merkusii

            Division Cycadophyta: cycads, example: Cycas rumphii

            Division Gynkgophyta: maidenhair tree, example: Gynkgo biloba

            Division Gnetophyta: gnetophytes, example: Gnetum gnemon

            Angiosperms

            Division Magnoliophyta: Flowering plants

                        Class Magnoliopsida: dicots, example: Mangifera indica

                        Class Liliopsida: monocots, example: Oryza sativa

1. NON VASCULAR PLANTS ARE DIVERSE

            The nonvascular plants, which include the liverworts and mosses, are non vascular plants and therefore lack true roots, stems and leaves. In the moss life cycle, the gametophyte is dominant. Antheridia produce swimming sperm that need external water to reach the eggs in the archegonia. Following fertilization, the dependent sporophyte consists of a foot, a stalk., and a capsule within which wind blown spores are produced by meiosis. Each spore germinates to produce a gamethophyte.

2. VASCULAR PLANTS INCLUDE SEEDLEES AND SEED PLANTS

            Vascular plants arose during the Silurian period of the Paleozoic era. The extinct rhyniophytes may be ancestral vascular plants. These plants had photosynthetic stems (no leaves or roots) with sporangioa at their tips. Most likely, the life cycle was similar to today’s ferns. The sporophyte, which is diploid and has vascular tissue, is the dominant generation in ferns. This separates gametophyte produces heterospores which develop into heterogametes. Every aspect of the life cycle is adapted to a dry environment.

3. FERNS AND ALLIES ARE SEEDLESS VASCULAR PLANTS

            The seedlees vascular plants include whisk fern, club mosses, horsetails, and ferns. Lycopods, horsetails and ferns were also trees during the Carboniferous period, although lycopods and horsetails are limited in diversity and rather small today. Seedless vascular plants  have a life cycle like that of the ferns.

            In ferns, the separate and water-dependent gametophyte (the heart-shaped prothallus) produces flagellated sperm in antheridia and egg in archegonia. Following fertilization, the zygote develops into the sporophyte, which has large fronds. On the underside of the fronds are sori(singular: sorus), each containing several sporangia. Here meiosis produces windblown spores, each of which develop into a prothallus.

            The Mesozoic era saw many geological changes as Pangaea formed and then broke apart. A mass extinction occured that paved the way for the diversification of the seed plants. Thoose seed plants that are trees have especially weel-developed roots and steems due to secondary growth of vascular tissue. Seed plants produce heterospores, microgametophytes, ang megagametophytes. The poolen grain replaces external flagellateds sperm, and the megagametophyte is retained within the ovule that develops into the seed.

4. GYMNOSPERMS HAVE NAKED SEEDS

            There are four divisions of gymnosperms (seed plants that bear naked seeda); the familiar conifers and the little-known cycads, ginkgo, and gnetophytes. In conifers, pollen (male) and seed (female) cones are produced by the sporophyte plant. On the under side of a pollen cone scale, there are two microsporangia that produce microspores; each becomes a micrgametopyte, or pollen grain.On the upper surface of a seed cone scale, there are two ovules, where meiosis produces one megasopre that develops into the megagametophyte. After windblown pollination, the pollen grain develops a tube through which sperm reach   the egg. After fertilization, the ovule matures to be a seed.

5. ANGIOSPERMS HAVE COVERED SEEDS

            Angiosperms (seed plants that bear seeds protected by a fruits) are more diverse than the other types of plants. Their success may be assosiated with climatic changes in the Cenozoic era.

            In a flower, the microsporangia develop within the anther portion of a stamen, and the megasporangia develop within ovules located in the ovary of the pistil. Pollination brings the mature microgamaetophyte (pollen grain) to the pistil, and the pollen tube brings the sperm to the ovule within the ovary. Angiosperms exhibit double fertilization; one sperm fertilizes the egg, and the other unites with the polar nuclei to form the endosperm, which is food for the embryo. The ovule develops into the seed, and the ovary becomes the fruit.

            Angiosperms have complex vascular tissue and are found in various habitats. Their reproductive organs are found in flowers. Animal pollination increases the chance of appropriate fertilization, and fruit production often assists the dispersal of seeds. 

Ecosystem

Ecosystem

Ecosystem is interaction between community and their abiotic component in an environment.

Components of ecosystem are biotic component and biotic component

Biotic component of ecosystem is consisting of living thing, such as plant, animal, human and decomposer.

Abiotic component of ecosystem is consisting of non living thing such as water, air, soil, temperature, humidity, etc.

Kind of biotic component based on the way to get energy are:

1. Autotrophic organism is the organism which can make food by itself with do photosynthesis process.
2. Heterotrophic organism is the organism which can not make food by itself, so it is get energy by eating another organism.

Kinds of biotic component based on their niche:

1. Producer is the organism which can produce food by itself, by convert inorganic substances into organic substances.
2. Consumer is the organism which can not produce food by itself, so this organism gets organic substance by consume another organism.
3.  Decomposer is the organism which can convert organic substances into inorganic substances as energy sources.

Kinds of biotic component (animal) based on kinds of their food:

1. Herbivore is the organism which eat plant as energy sources
2. Carnivore is the organism which eat animal as energy sources.
3. Omnivore is the organism which eats plant and animal as energy sources.

Units of ecosystem:

1.  Individual is one organism.

 

2. Population is a group organisms included one species.

3. Community is a group of organisms that consist of several populations.

4. Ecosystem is interaction between community and their environment.

5. Biome is an ecosystem which influenced by climate and geographical location.

6. Biosphere is all of ecosystem in the earth or the earth and its content.

Kegiatan Siswa SMP N 2 Semarang

Ini adalah salah satu kegiatan belajar dan mengajar siswa SMP N 2 Semarang. Mereka sedang belajar tentang bagaimana seleksi alam bekerja di alam dengan menggunakan media kupu-kupu kertas yang berwarna-warni yang ditempelkan pada sehelai kertas asturo dengan warna tertentu. Mereka asyik sekali dalam kegiatan ini.....hmmm...sukses ya nak!!!

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