Asexual/sexual reproduction Flashcards
what is sexual reproduction
2 seperate organisms contribute genetic information to create another organism
what is asexual reproduction
involves 1 parent and the kid comes from 1 parent cell and divides into identical daughter cells - clones
binary fission
parent undergoes cell division to produce 2 genetically identical cells, offspring is smaller than the parent cell, allows for rapid growth,
budding
starts as a bud on a parent, continues to go through cell division until it breaks off the parent, once it breaks off it will reproduce
spores
mould reproduces using spores, molds form spores that are like clones to the mold cells they come from. spores release into the air by a structure called sporangrum. parent producee 4-8 spores during cell division
when can chromosomes be seen?
once they’ve duplicated during interphase and condensed during mitosis or meiosis
how many chromosomes do humans inherit from their parents
23 from the mom and 23 from the dad - referred to as the haploid number
Meiosis 1
matching chromosome pairs move to opposite poles of the cell - 2 daughter cells result
Meiosis 2
chromatids of each chromosome are pulled apart
genetic variation - crossing over
in meiosis 1 chromatids of chromosome pairs can cross over each other and exchange DNA segments
external fertilization advantages
little energy needed to mate, large numbers of offspring produced, offspring can be spread widely in an environment
disadvantages for external fertilization
lots of gamete’s wont survive, many eggs wont be fertilized, not protected by parents so many offspring can die
internal fertilization advantages
embryo protected from predators, more likely to survive as many species protect them while they mature,
internal fertilization disadvantages
more energy required to mate, less offspring at a time, more energy to raise and care for offspring
