Science notes

• Ferns

  Popular ornamental plants, up to 12,000 species around the world
• Fern life cycle

  1. Spores produced on underside of fronds

  2. Spores germinate into heart-shaped plant with male and female organs

  3. Sperm and egg cells fertilize to form zygote

  4. Zygote grows into young fern plant

  5. Fern develops roots, stems, and leaves
• Mosses

  Small flowerless plants, have rhizoids instead of roots, grow in moist areas
• Moss life cycle

  1. Spores released from capsule

  2. Spores grow into protonema

  3. Protonema becomes leafy green stem with reproductive organs

  4. Male and female sex cells fertilize to form zygote

  5. Zygote develops into stalk with spore capsule
• Cone-bearing plants (conifers)

  Reproduce through male and female cones
• Conifer reproduction

  1. Male cones release pollen

  2. Pollen lands on female cone

  3. Sperm fertilizes egg to form zygote

  4. Zygote develops into embryo

  5. Embryo develops into seed protected by cone scales

  6. Seed is released and germinates into new conifer tree
• Vegetative propagation


  Form of asexual plant reproduction using parts of the plant like buds, stems, roots, leaves
• Artificial vegetative propagation

  • Stem cuttings
  • Layering
• Vegetative propagation helps increase plant population
• Nonflowering plants reproduce through spores
• Predator


  An organism that hunts and eats other organisms
• Prey


  An organism that is hunted and eaten by a predator
• Competition


  An interaction between organisms of the same kind or different species that live near each other, competing for limited resources such as food, water, and space
• Competition


  • Rice plants and weeds in a farm
  • Beetles competing with each other
• Coral reef


  • Called "rain forest of the aquatic ecosystem"
  • Shelters different species of fish, invertebrates, phytoplankton, and zooplankton
  • Phytoplankton serve as the producers
  • Zooplankton and other organisms eat the phytoplankton
• Mangrove swamps


  • Found in estuaries, where the river and the sea or ocean meet
  • Water is brackish (partly salty)
  • Serve as breeding grounds for invertebrates and fishes
  • High level of nutrients because the nutrients from the ocean, sea, and river flow through them
  • Nitrogen-fixing bacteria present
  • Dominant organisms are plants called bakawan, tangal, and busain
  • Molluscs, such as oysters, feed on plants
  • Phytoplankton, zooplankton, various invertebrates, and fishes thrive
• Tropical rain forests


  • Situated in the tropics, near the equator
  • Humid and warm
  • Highest number of organisms among terrestrial ecosystems
  • Animals feed on fruits of tall trees
  • Trees serve as habitat for many animals
  • Tall trees receive abundant sunlight, vines reach these trees to capture sunlight
  • Plants live on the trunks of big trees (ferns, orchids, hanging plants)
  • Interactions include predation (snakes preying on small animals), competition (big trees competing for sunlight and nutrients), parasitism (deer and tick), commensalism (big trees and epiphytes), mutualism (termite and flagellate)
• Friction


  A contact force that exists when one surface slides over another, affected by the irregularities in the surfaces, resists motion
• An object slides on the surface of another

  Friction is created, the force of friction always acts opposite to the direction of motion, friction slows down a moving object or prevents an object from moving
• Pushing a book on top of a table

  Friction prevents the book from moving immediately or continuously
• Walking on a pavement

  Friction enables you to run and walk, prevents you from sliding
• Static electricity


  Formed when two objects are rubbed together causing the electrons to move from one object to another
• Kinetic friction


  Can be sliding, rolling, or air friction
• Sliding friction


  Acts on dry solid objects sliding on a surface
• Rolling friction


  Slows down the motion of wheels on a solid surface, weaker than sliding friction and static friction
• Air friction


  Acts on an object that is falling or moving through the air, slows down the fall of an object
• Air friction


  Affected by the surface area of the falling object, a wider surface area encounters greater air friction
• Increasing friction


  By increasing the roughness of the surface, using pebbles, rubber sheets, cloth, tractions on shoe soles
• Decreasing friction


  By making the surface smooth, applying lubricants like wax and oils, using wheels or rollers
• Gravitational force, or gravity, is the downward force that acts on every object and pulls objects toward the center of Earth
• When you let go of an object, it will fall toward the ground due to the effect of gravity
• Energy


  The ability to do work or any activity that requires actions
• Different forms of energy

  • Mechanical energy
  • Chemical energy
  • Sound energy
  • Thermal energy
  • Radiant energy
• Potential energy


  Stored energy possessed by objects due to their position relative to the ground
• Kinetic energy


  Energy possessed by objects that are moving
• Sound energy


  Energy possessed by sound waves produced by vibrating particles
• Thermal energy


  Energy possessed by an object due to the movement of particles within, released in the form of heat
• Geothermal energy


  • Energy from groundwater and rocks beneath the earth
• Hydrothermal energy


  • Energy of water from the body
• Radiant energy


  Also known as radiation, energy from electromagnetic waves that can travel through solid, liquid, and gases, can be used to treat muscular pains and cataracts, and produce heat