Reproduction Flashcards
what is sexual reproduction
genetic information from 2 organisms combined to produce off spring which are genetically different to their parents
how do the parents produce gametes
through meiosis
what does each gamete in a humans contain
23 chromosomes, half of the the number of chromosomes in a normal cell
how is an off spring formed through gametes
the gametes from the male and female fuse to make a cell with the full number of chromosomes (46)
why does the offspring have a mixture of their parent’s genes
because they have half of the genetic info (23 chromosomes) from each parent combining to form an organism with its own specific combination of chromosomes and genes
why do we mix half of each parent’s genetic info to create an off spring
to produce variation within the species to increase their chances of survival
what other organisms do this apart from humans and animals and how
- flowering plants
- they produce their eggs and their form of sperm is pollen
what does asexual reproduction consist of and what does it result in
only one parent, so the offspring are genetically identical to the parent
what does asexual reproduction happen through
mitosis, which consists of a new cell dividing into two on its own
what are two cells with identical genetic information referred to as
clones of each other
what does no fusion of two gametes mean
- theres no mixing of chromosomes
- so no genetic variation between offspring and parent
what organisms reproduce asexually
bacteria, some animals and some plants
how is variation, produced from sexual reproduction, an advantage
- increases chance of a species surviving a change in environment
- a change may kill some in the species, but all are varied so some will survive what others cant
how does variation benefit a species general evolution
- in the event of a change in the environment, the ones better adapted survive
- they are more likely to breed successfully
- pass genes on the offspring which populate species
- result is a stronger species (natural selection)
how is variation used in selective breeding
- to speed up natural selection
- organisms with desirable characteristics are bred
- offspring has desirable characteristics too
- so it allows us to produce animals with characteristics we want
