D3.1 - reproduction Flashcards
chemotaxis
movement in response to a chemical signal
fertilisation
fusion of gametes
morphology
study of the form and structure of organisms
what is the role of meiosis in the sexual life cycle?
- breaks up the parental combination of alleles
- produces haploid gamete cells in a reduction division, meaning only half the genes for a parent can be passed onto the offspring
what is the role of fertilisation in the sexual life cycle?
- produces a new combination of alleles
- fusion of haploid gametes nuclei restores the diploid number of chromosomes as homologous pairs with 1 coming from the male parent and 1 coming from the female parent
what are the characteristics of sexual reproduction?
- involves 2 parents
- fusion of male and female gametes
- new allele combination which leads to genetic variation in the offspring, unique to both parents
- cell division involves meiosis
- chromosome numbers are halved during gamete formation and re-established during fertilisation
- usually slower and requires more energy
- new allele combination provides variation needed for adaption to the changed environment
what are the characteristics of asexual reproduction?
- involves 1 parent
- no fusion of gametes
- no new allele combinations , so offspring are genetically identical to the parent
- cell division involves mitosis or binary fission
- chromosome numbers are maintained throughout
- usually faster and requires less energy
- production of genetically identical offspring allows colonization by individuals that are already adapted to the existing environment
what are the characteristics of males in sexual reproduction?
- gamete is small and motile to efficiently move to the female gamete
- gamete has less food reserves
- releases millions of gametes
- males typically mate with females as they aren’t involved in parental care and breeding success is often based on having large numbers of offspring
what are the characteristics of females in sexual reproduction?
- gamete is large and immotile
- gametes contain enough nutrients to support early development of the embryo
- females tend to choose mates with particular traits that indicate health and ability to provide support and breeding success is based on the quality of parental care
what are the components of the female reproductive system?
- ovary
- oviduct
- uterus
- endometrium
- cervix
- vagina
what are the components of the male reproductive system?
- vas deferens
- seminal vesicle
- prostate gland
- epididymis
- urethra
- testis
what is the function of the ovary?
where oocytes mature prior to ovulation and from where oestradiol and progesterone are secreted into the bloodstream
what is the function of the oviduct?
transports the oocyte/early embryo from the ovary to the uterus
what is the function of the uterus?
the muscular organ where the early embryo implants and develops
what is the function of the endometrium?
vascular inner lining of the uterus wall