The first known single-celled organisms appeared on Earth about 3.5 billion years ago, roughly a billion years after Earth formed. More complex forms of life took longer to evolve, with the first multicellular animals not appearing until about 600 million years ago.
Human and the natural ones can change the ecosystem
MASS: because it is the measure of the amount of matter in an object
Answer:
C)Parental: 41% Dr, 41% dR; recombinant: 9% DR, 9% dr.
Explanation:
The notation Dr/dR for genotypes means that one homologous chromosome has the alleles Dr and the other homologous chromosome has the alleles dR.
The heterozygous plant Dr/dR will produce 4 types of gametes: two identical to the chromosmes the individual has in its somatic cells (called parental), and two gametes which will be a mix of the alleles in the homologous chromosomes (called recombinant).
- Dr: parental
- dR: parental
- DR: recombinant
- dr: recombinant
To calculate the frequency of each type of gamete, we must use the formula:
Distance (map units) / 100 = frequency of recombination.
18 mu / 100 = 0.18.
The total frequency of recombination between the genes D and R is 0.18, but every time crossing over happens, two recombinant gametes are generated. Therefore, each recombinant gamete will have a frequency of 0.18/2=0.09 = 9%.
The frequency of parental gametes will be:
1 - frequency of recombinant gametes
1 - 0.18 = 0.82
But there are 2 parental gametes, so each of them will have a frequency of 0.82/2=0.41 = 41%.
