inheritance variation and inheritance

• what does asexual reproduction involve

  1 parent

  no fusion of gametes

  production of genetically identical offspring
• process of meiosis

  chromosomes in diploid cells replicate

  chromosomes move to opposite sides of cell

  cell divides for first time

  divides again

  4 haploid cells are produced, each with a single set of chromosomes
• what's the genome


  entire genetic material of organism
• what's a gene 


  small section of DNA on a chromosome
• how do plants reproduce asexually

  strawberries send out long shoots called runners which touch ground and grow new plant

  daffodils produce bulbs which grow into new plants
• what's the genotype


  combination of alleles present in a gene
• what's the phenotype 


  how the alleles are expressed (what characteristics appear)
• homozygous 


  when both alleles are present at the same time eg BB
• heterozygous 


  when the two alleles are different eg Bb
• what's polydactyly 


  having extra fingers or toes - caused by a dominant allele
• what's cystic fibrosis caused by

  a recessive allele
• natural selection 


  individuals have variation in phenotypes

  individuals with phenotypes best suited to the environment will survive

  they'll breed and pass allele down to offspring
• how are fossils formed

  from hard parts of animals that don't decay easy

  preserved traces of organisms
• why are there gaps In fossil records

  many forms of life were soft bodied

  traces destroyed by geological activity
• process of selective breeding

  choose parents that shows desired characteristics

  breed them together

  choose best characteristics from offspring and continue over generations
• how have plants been generically engineered

  to be resistant to disease, insects or herbicide attacks

  produce bigger fruits
• what was carl Linnaeus' class order

  kingdom - phylum - class - order - family - genes - species
• carl Worse three domain system

  archaea (primitive bacteria usually living in extreme conditions)

  bacteria (true bacteria)

  eukaryota (protists, fungi, plants, animals)
• reasons for extinction

  new predators

  disease

  catastrophic event

  changes to environment

  more successful competitors