SCIEXAM

• 1. Environment


  is anything that affects an organism in its lifetime.
• ORGANISM


  Smallest unit of an ecosystem
• Ecology


  is the branch of biology that studies the interactions between organisms and their environment
• Ecosystem


  is composed of the organisms in an area that are interacting with both biotic and abiotic factors
• Population


  A group of organisms of the same species form
• Community


  Various species constitute different populations of species and form
• Food chain


  is a linear sequence of organisms through which energy and nutrients pass as one organism feeds on another organism
• Food Web


  is a network of interconnected food chains
• Biomass


  is the weight of the organisms at a trophic level
• Trophic Level


  is described as a step or stage in the flow of energy through an ecosystem
• Natural Ecosystem


  results from the interaction between organisms and their environment.
• Terrestrial Ecosystem


  are land-based interactions of biotic and abiotic factors in a given geographic area
• Aquatic Ecosystem


  are water-based, and they can be classified as freshwater or marine ecosystems
• Biome


  is a geographic area on Earth that is classified based on the plant and animal species that live in it.
• temperature and precipitation (moisture)


  Two key environmental factors can be used in determining which biomes are found:
• Primary Productivity


  is the amount of energy produced by photosynthetic organisms in a given community.
• Chaparrals


  are characterized by the presence of thorny bushes and tangled shrubs
• (tropical rainforest, savanna, desert, temperate grassland, temperate deciduous forest, temperate evergreen forest, taiga, tundra)


  Eight Principal Biomes
• Freshwater Ecosystem


  can be categorized as stationary or running.
• Euphotic Zone


  top of a lake where abundant kinds of phytoplankton and zooplankton can be found.
• Littoral zone


  region of the lake with rooted vegetation.
• Limnetic Zone


  part of the lake with no rooted vegetation.
• Photic Zone


  1. uppermost layer where photosynthetic activity is limited to the well-lit.
• Aphotic Zone


  1. is permanently dark because sunlight cannot reach it.
• intertidal zone, Pelagic zone, Benthic zone, Abyssal zone.


  Division of marine ecosystems based on depth and on distance from the shore:
• Evolution


  1. refers to a change in the characteristics of organisms over time
• Theory


  1. an explanation based on well-substantiated evidence that has been tested repeatedly and is what is accepted by the scientific community.
• FOSSILS


  1. are the remains of organisms that have been preserved in different ways.
• PETRA


  Petrification (from the Greek word
• stone


  petra means
• Homo Luzonensis


  1. fossils that were found in Callao Cave in Cagayan Valley consist of seven teeth, bones of the

  hand and foot, and a part of a femur.
• PALEONTOLOGISTS


  is a scientist who studies fossils
• Homologous an Vestigial


  Anatomical evidence is divided into
• Vestigial organs


  parts of organisms that have been reduced in size significantly over time.
• Linus Pauling and Emile Zuckerland


  1. introduced the concept of molecular clock
• Molecular clock


  measures the number of changes or mutations that occur in the gene sequences of different species from the past.
• Gene Pool


  is the total collection of genes in a population
• Genetic drift


  is a change in the gene pool of a group.
• Godfrey Hardy and Wilhelm Weinberg


  They independently proposed a principle that states that the frequency of alleles in a gene pool will remain constant unless one or more factors or other agents will cause the frequency to change
• Mass extinction


  factors all lead to the disappearance of a vast number of organisms.