SCIENCE REVIEWER
#12 LOCAL AND GLOBAL ENVIRONMENTAL ISSUES/PROBLEMS
PRINCIPAL CAUSES OF DEFORESTATION
1.
2.
3.
4.
5.
ILLEGAL FARMING
KAINGIN FARMING
FOREST FIRES
CONVERSION OF ALGRICULTURAL LANDS TO HOUSING PROJECTS
TYPHOONS
EFFECTS OF DEFORESTATION
1. SOIL EROSION
2. FLOODS
3. DEPLETION OF WILDLIFE RESOURCES
MAJOR CAUSE OF WILDLIFE EXTINCTION
- is the loss of habitat
CORAL REEF DESTRUCTION
- is caused by dynamite fishing and muro-ami
MANGROVE DESTRUCTION
- is caused by overharvesting and conversion of area into other uses EUTROPHICATION - nutrients are
washed away from the land to enrich bodies of water
ACID RAIN
- is a result of air pollution mostly from factory and motor vehicles
CARRYING CAPACITY OF THE ENVIRONMENT
#13 CAUSES OF SPECIES EXTINCTION
 POPULATION
- pertains to the number of organisms of the same species living in a certain place
 BIODIVERSITY
- refers to the variety of life in an area
POPULATION SIZES VARY AMONG ORGANISMS
They change with the number of births, they also change when a member dies or move out an
ecosystem
 LIMITING FACTORS
o are environmental conditions that keep a population from increasing in size and help
balance ecosystem
 CARRYING CAPACITY
o is affected by changes in the environment
 EXTINCTION
o occurs when the last member of that species dies
 WHEN THE POPULATION OF SPECIES BEGINS DECLINING RAPIDLY
o the species said to be threatened species
 SPECIES IS ENDANGERED
o is endangered when its population has become low that is possible of becoming extinct
 HUMAN ACTIONS
o have resulted in habitat loss and degradation that have accelerated the rate of
extinction
CAUSES OF SPECIES EXTINCTION
1.
2.
3.
4.
5.
HUNTING AND TRAPPING
TAKING ANIMALS FOR PROFIT
DESTRUCTION OF HABITAT
POLLUTION
OVERHARVESTING
# 14 LIFE ENERGY; PHOTOSYNTHESIS
 PHOTOSYNTHESIS
o is a process of food making done by plants and other autotrophic organisms
AUTOTROPHIC ORGANISMS REQUIRE:
1. LIGHT ENERGY
2. CARBON DIOXIDE (CO2)
3. WATER (H2O)
TO MAKE FOOD (SUGAR)
 PHOTOSYNTHESIS
o primarily takes place in the leaves depending on the presence of chlorophyll
PARTS OF THE LEAVES
1.
2.
3.
4.
UPPER AND LOWER EPIDERMIS
MESOPHYLL SPONGY LAYER
VASCULAR BUNDLES
STOMATA’S
 UPPER AND LOWER EPIDERMIS
o protect the leaves and has nothing to do with photosynthetic process
 MESOPHYLL
o has the most number of chloroplasts that contain chlorophyll. They are important in
trapping light energy from the sun
 VASCULAR BUNDLES
o phloem and xylem serve as transporting vessels of manufactured food and water
 CARBON DIOXIDE AND OXYGEN
o were collected in the spongy layer and enters and exits leaf through the stomata
PARTS OF CHLOROPLASTS
1.
2.
3.
4.
OUTER AND INNER MEMBRANES
INTERMEMBRANE SPACE
STROMA
THYKALOIDS STACKED IN GRANA
 CHLOROPHYLL
o is built into the membranes of the thylakoids. It absorbs white light, but it looks green
2 STAGES OF PHOTOSYNTHESIS
1) LIGHT-DEPENDENT REACTION
- happens in the presence of light. It occurs in the thylakoid membrane and convert light Energy
to Chemical Energy. The energy harvested during the stage is stored in a form of ATP (Adenosine
Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate Hydrogen)
2) CALVIN CYCLE(DARK REACTION)
- is a light-independent phase that takes place in the stroma and converts Carbon Dioxide (CO2)
into sugar.
CHEMICAL EQUATION FOR PHOTOSYNTHESIS
CARBON DIOXIDE + WATER + SUNLIGHT = GLUCOSE + OXYGEN
OR
CO2 + H2O + SUNLIGHT = C6H12O6 + O2
 PLANTS ARE CALLED UNIVERSAL PROVIDERS
#16 CELLULAR RESPIRATION ALL HETEROTROPHIC ORGANISMS INCLUDING MAN, DEPEND DIRECTLY OR
INDIRECTLY ON PLANTS AND OTHER PHOTOSYNTHETIC ORGANISMS FOR FOOD.
 ORGANISMS NEED FOOD AS THE MAIN SOURCE OF ENERGY
 THE FOOD MUST BE DIGESTED TO SIMPLE FORM SUCH AS GLUCOSE, AMINO ACIDS AND
TRIGLYCERIDES.
 GLUCOSE INSIDE THE CELL IS BROKEN DOWN TO RELEASE ENERGY.
 THIS STORED ENERGY IS HARVESTED IN THE FORM OF ADENOSINE TRIPHOSPHATE (ATP)
ATP is a high-energy molecule needed by working cells
 CELLULAR RESPIRATION
o occurs in the mitochondria of the cells
 ORGANISMS RELEASE STORED ENERGY IN FOOD THROUGH THE PROCESS OF RESPIRATION
 RESPIRATION
o breaks down glucose into carbon dioxide, water, and energy (ATP) in the presence of
oxygen. SUMMARY EQUATION OF RESPIRATION
GLUCOSE + OXYGEN = CARBON DIOXIDE + WATER + ATP
THE BREAKDOWN OF GLUCOSE 3 MAJOR STEPS:
1. GLYCOLYSIS
2. KREBS CYCLE
3. ELECTRON TRANSPORT CHAIN
GLYCOLYSIS
The 6-carbon sugar, glucose, is broken down into 2 molecules of 3-carbon molecule called pyruvate. This
change accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.
KREBS CYCLE
-occurs in the mitochondrial matrix and generates a pool of chemical energy
PYRUVATE
Is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule.
Chemical energy is released and captured in the form of NADH, FADH2 and ATP.
SPECIFIC REGION OF THE FOLLOWING



GLYCOLYSIS – CYTOPLASM
KREB’S CYCLE – MITOCHONDRIA
OXIDATIVE PHOSPHORYLATION – INNER MITOCHONDRIAL MEMBRANE