B15

• Ways fossils may be formed

  • From the hard parts of animals that do not decay easily, like bones, teeth, shells, claws
  • From parts of organisms that have not decayed because some of the conditions for decay are absent, for example, fossils of animals preserved in ice
  • Parts of the organism being replaced by other materials, such as minerals, as they decay
  • As preserved traces of organism, such as footprints, burrows, and rootlet traces
• Mutations of pathogens produce new strains; some are resistant to antibiotics
• Antibiotics kill the individual pathogens that have not developed resistance
• The resistant pathogens survive and reproduce, and a whole population of a resistant strain develops. This is an example of natural selection
• Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium that has evolved through natural selection
• Ways to slow down the rate of development of resistant strains

  • Antibiotics should not be used for mild infections
  • The correct antibiotics must be prescribed
  • Patients should always complete each course of antibiotics
• Extinction means that a species that once existed has completely died out
• CAUSES OF EXTINCTION: new disease, enivronmental change, new predator may evolve or be introduced to new area, new competitor may evolve or be introduced to new area, single catastrophic event that destorys habitat and natural changes in species over time
• Classification is grouping organisms
• Linnaeus classified organisms into the order: kingdom, phylum, class, order, family, genus, species
• the largest group in classification are kingdoms and Linnaeus had 2 - animals and plants
• the smallest group in classification are species, members of species are similar and can breed together to produce fertile offspring
• the class group classes organisms into mammals, reptiles, amphibians, fish, birds and invertebrae
• the 3 domains are divided into 6 kingdoms
• speciation is where populations become so different that successfully interbreeding is no longer possible
• new species can rise from existing species if a group becomes isolated from rest
• geographical isolation could occur if an island seperates from mainland or if new river or mountain range or old crates seperates two areas
• isolation is where 2 populations of species becomes seperated
• genetic variation is that each population has wide range of alleles that control their characteristics
• in speciation, after geographical isolation, natural selection will occur so both populations have diff characteristics that are beneficial to environment they are in
• the three domains are called archaea, bacteria and eukaryota
• archaea are primitive forms of bacteria including extremophiles and has 1 kingdom which is archaebacteria
• the domain bacteria contains tru bacteria and cyanobacteria and has one kingdom which is eubacteria
• the domain eukaryota, all have cells that contain nucleus and has 4 kingdoms which are protista, fungi, plants and animals
• the inheritance of accquired characteristics stated that characteristics that develop during an organism's lifetime that can be passed on to the next generation
• Lamarck's theory involved two main ideas: a characteristic that is used frequently by organism becomes better and passed onto offspring and characteristics not used gradually disappears
• Darwin's theory of natural selection states that: individuals in species show wide range of variation, individuals with characteristics most suited to environment have higher chance of survival and reproduce
• the biggest influences in survival of species are changes in environment
• fossil evidence shows that there has been mass extinctions on global scale
• IDEAS ABOUT DINOSAURS' EXTINCTION: collision of giant asteroid caused huge fires, earthquakes, landslides and tsunamis and dust masked sun causing darkness and lower temps so plants couldn't grow and sea ice melting and cooling sea temp about 9ºC