human evolution

• 4 key points about natural selection

  1. Individuals with a species show variation
  2. Only the individuals best adapted to the environment will survive
  3. Only the survivors will pass on their genes
  4. Individuals with a species compete for resources
• Mutation

  Variation

  Adaption/advantage

  Survival

  Reproduction

  Inherit
• What are the 5 species?

  1. Homo sapiens
  2. Homo erectus
  3. Homo habilis
  4. Lucy
  5. Ardi
• What is an antibiotic?


  Is a substance that kills off bacteria
• What is a mutation?


  A mutation is a change in a gene/DNA

  A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes.
• What are the 5 kingdoms?

  1. Animals
  2. Plants
  3. Fungi
  4. Protists
  5. Prokaryotes
• What is genetic engineering?

  The deliberate modification of the characteristics of an organism by manipulating its genetic material
• What is evolution?

  a process witnessed in living entities wherein gradual changes are observed in the characteristics of species over generations attributed to the process of natural selection
• Animals

  Multicellular, Cells have nuclei, No cell walls
• Plants

  Multicellular, Cells have nuclei and chloroplasts, Cellulose cell walls
• Fungi

  Multicellular, Chitin cell walls, Feed off dead matter, Cells have nuclei
• Protists

  Mostly unicellular, Cells have nuclei, Some have cell walls (not chitin)
• Prokaryotes

  Unicellular, No nucleus, Flexible cell wall
• What is natural selection?


  The natural process whereby the best-adapted individuals survive longer, have more offspring and thereby spread their characteristics. Sometimes referred to as 'survival of the fittest'.
• Bacteria

  pathogen, microorganism that causes disease
• Antibiotic resistance

  • Bacteria can evolve quickly, due to reproducing at a fast rate.
  • Mutations of bacteria produce new strains
  • Some bacteria may become resistant to the antibiotics, penicillin, and cannot be destroyed
  • Evolution of bacteria is an example of natural selection
• Development of resistance

  1. random mutation occur in the genes of individual bacterial cells
  2. some mutations protect the bacterial cell from the effects of the antibiotic
  3. bacteria without the mutation die or cannot reproduce when the antibiotic is present
• In order to reduce the rate of development of antibiotic resistant strains:

  • doctors should not prescribe antibiotics inappropriately, such as for the treatment of non-serious infections
  • patients should always complete the full course of antibiotics to ensure all bacteria are killed and none survive to mutate and form resistant strains
  • the agricultural use of antibiotics should be restricted
• Evidence for evolution

  1. fossils
  2. bacteria
  3. extinction
• What are fossils?

  Fossils are the preserved remains of dead organisms that lived millions of years ago
• Fossils can be preserved in three main ways:

  1. Hard body parts. these are things that don’t decay easily like skeletons, bones and teeth.
  2. No decay. This happens in environments like amber, tar pits, ice glaciers and peat bogs. The microbes that decay organisms can’t survive there, so decay can’t happen.
  3. Buried traces. This usually occurs when an organism is buried in a soft material like clay, like casts, burrows, footprints and impressions.
• how do fossils provide evidence for the theory of evolution?

  they are biological photographs over millions of years that demonstrate organisms gradually getting more and more complex over time
• An example of a bacteria that has become resistant to antibiotics is MRSA
• An example of natural selection; (Bacteria)


  where a mutation has caused an organism to have a beneficial trait, and the genes for that trait are inherited by the subsequent generations of offspring.
• What is extinction?

  Extinction is when there are no remaining individuals of a species alive.
• Five things that might lead to extinction

  1. New diseases.
  2. New predators
  3. New competitors.
  4. Changes to the environment, such as climate change
  5. A single catastrophic event, like a volcanic eruption or an asteroid collision.
• Why does extinction happen?

  Organisms that don’t have useful traits or are poorly adapted to their environment, and therefore less likely to survive, reproduce and so on and so forth, may become extinct.
• Fossil record

  Fossil remains have been found in rocks of all ages. Fossils of the simplest organisms are found in the oldest rocks, and fossils of more complex organisms in the newest rocks

  
•  Fossils are found in rocks and can be formed from:

  • hard body parts, such as bones and shells, which do not decay easily or are replaced by minerals as they decay
  • parts of organisms that have not decayed because one or more of the conditions needed for decay are absent for example, dead animals and plants can be preserved in amber, peat bogs, tar pits or in ice
  • preserved traces of organisms, such as footprints, burrows and rootlet traces - these become covered by layers of sediment, which eventually become rock
• Evidence for human evolution

  1. Ardi; she dates back to 4.4million years ago, she had very long arms, able to walk upright, long toes. The bones that make up Ardi's feet suggest that humans and chimpanzees evolved separately.
  2. Lucy; she dates back 3.2million years ago, she walked in an upright position (like humans), small ape-like skull. Lucy's foot bones show that she had similar feet to modern humans but with much more curved toes.
• Tools as evidence for human evolution

  The tools they started of with were just large rocks but as time went on the tools started get sharper and more refined, detailed. This is an example of evolution.

  
• Living things can then be ranked according to:

  • phylum
  • class
  • order
  • family
  • genus
  • species
• The Linnean System classified organisms into different groups depending on their structure and characteristics
• What's classification?

  group organisms together that share similar characteristics
• The Linnean

  Kingdom, Phylum, Class, Order, Family, Genus, Species
• Species

  group of organisms capable of interbreeding and producing fertile offspring. So all dogs, despite their different breeds, size difference and everything, can interbreed to have fertile offspring, because they’re all one species
• Binomial system

  1. ‘homo’ is the genus,
  2. ‘sapiens’ is the specie
• Why is the binomial system helpful?

  it allows scientists to name and identify individual species.
• Three domain system

  1. Archaea (primitive bacteria); These cells usually live in extreme environments. They have no nucleus and have unused sections of genes.
  2. Bacteria (true bacteria); Bacteria cells have no nucleus and no unused sections of genes.
  3. Eukaryota (including protists, fungi, plants and animals); These have a nucleus and have unused sections of genes.
• What is this diagram showing?

  Three domain system