In most vertebrate species with internal fecundation the females have reproductive cycles with fertile periods. During this period the female secretes pheromones (odoriferous substances that attract the male of the species) from the skin and mucosae. The presence of the male individual and his pheromones also stimulates the release of pheromones by the female. (Many animals also use pheromones for territorial demarcation and for signal transmission between individuals about the location of dangers and food.)
The sexual behaviour of females during receptive period can be sensed by males through their physical behaviour and body smell. The release of pheromones directs the animals towards sexual activity.
Generally how does a male animal realize that the female is receptive to copulation?
How does the female urethra differ from the male urethra?
A female animal with genotype A/a; B/b is crossed with a double recessive male a/a; b/b. Their progeny include: 452 A/a; B/b 459 a/a; b/b 72 A/a; b/b 67 a/a; B/b How many map units apart are loci A and B?
describe how the Sxl gene in Drosophila influences the differentiation between male and female. How does Sxl get activated? How does the active Sxl enzyme changed the product of the Dsx gene?
Ferns 1)what are the male and the female located? 2)How does the sperm get to the egg? 3)What features of the this group is more complex or advanced compared to Bryophytes and , how are they less advanced the Gymnosperms and Angiosperms? 4)Finally, explain the significance of both of these groups
Where would fertilization occur? Does it always work? Why and why not? How does male and female reproductive anatomy work together to fertilize and oocyte (egg) and allow for embryonic development?
is this female or male?how many chromosomes are in this karyotype?
for female and male what is the approx. number of stem cells at the beginning of life? do they both use meiosis 1 and 2 for the production of gametes? how long does it take for gametes to mature in both male and female ?
A female who does not carry the hemophilia gene and a male hemophiliac (he has made it to his reproductive years thanks to recombinant DNA technology that has produced clotting factor for him) produce four children. Their four children (two of each sex) have normal clotting blood. One of the daughters marries a non-hemophiliac male and has three non-hem offspring (two males and one female). The other daughter of generation II marries a hemophiliac male and they have one male...
A cross is made metween a male AaBbCcDd and a female AaBBccDd a. How many different germ cells are generated in the male? b. how many different germ cells are generated in the female? C Assume that all four genes exhibit complete dominance, how many different phenotypes can be generated in this cross?
The following data show how many days female birds are sexually receptive in a given season. Each observation below is completely independent except for treatment. You want to know if the treatment causes a significant change. The appropriate test to use is: Group days Control 4.6 Control 2.3 Control 7.7 Control 6 Control 4.6 Control -1.2 Treatment 15.5 Treatment 11.3 Treatment 5.4 Treatment 16.5 Treatment 11.3 Treatment 11.4 Treatment 7.7 group days Control 4.6 Control 2.3 Control 7.7 Control 6...