B13 - Reproduction Flashcards
Asexual reproduction
- involves only one parent
- cells divide by mitosis only
-no fusion of gametes
-no genetic variation = identical DNA
eg of organisms that asexually reproduce
-daffodils
-strawberries
-body cells
Sexual reproduction
-involves gametes which fuse to form a zygote
-inherits genetic material from parents = genetic variation
gametes are formed by and why
meiosis
-chromosome number is halved
plants gametes
egg cells
pollen
animals gametes
egg cells and sperm
sexual reproduction pros
-offers variation
pro of variation
allows long term survival of species
- evolution and adaption
meiosis meaning
chromosome number is reduced by half
-so dna is inherited by both parents
egs cells made in
ovaries
sperm made in
testes
process of meiosis
-genetic info is copied = 4 sets of chromosomes
-each chromosome forms a pair of chromatids
-cell divides once so both pairs are split
- cells divide once more so each pair is split = forms 4 gametes w 1 set of chromosomes
genetic variation in gametes
-random mixture of original chromosomes
= each are diff
fertiliation
mitosis to form zygote
-new cell divides
-cells differentiate into tissues/organs
alleles
different forms of the same gene
pros of asexual
-only 1 parent
-time/energy efficient
-faster
-large number of identical offspring
-goof for fast food production
con of asexual
if 1 dies all will as there is no genetic variation to assist with adaptations
sexual reproduction pros
-variation
-allows for natural selection
pros of selecetive breeding for food
-increase yeild
sexual reproduction cons
-requires 2 parents
-slower
-more energy needed
asexual in fungi
-common
-fungal spores divide by mitosis
sexual in fungi
2 hyphae nuclei fuse to form 1 hypahe
-2 sets of chromosomes
undergoes meiosis = haploid spores
pollination
pollen from one flower must reach female parts of another
adaptations for pollintaion
-attract animal pollinators to carry pollen by wind
fusion of plant gametes
pollen and egg cells = seeds
-variation
asexually in plants pro
-new plant is formed even if plant dies
con asexually in plants
no variation
malaria parasites sexually
-in mosquitoes
-drop in temp triggers this in blood cells
malaria parasites sexually process
-20 minute window when
-sexual forms develop and burst out of blood cells
-meet to form zygote
-zygotes undergo meiosis to produce new asexual parasites
malaria parasites asexually
in human hosts
-in liver/blood cells
