the evolutionary ecology of gynogenesis
... 2000), which do not show meiosis and recombination. During sexual reproduction any given individual pays a cost: It reduces the number of genes passed on to the next generation by half [cost of meiosis (Williams 1975)]. Additionally, for sexual reproduction two sexes are needed to restore the parent ...
... 2000), which do not show meiosis and recombination. During sexual reproduction any given individual pays a cost: It reduces the number of genes passed on to the next generation by half [cost of meiosis (Williams 1975)]. Additionally, for sexual reproduction two sexes are needed to restore the parent ...
Sexual Reproduction in Seedless Plants
... Spores form by meiosis inside the spore capsule. Therefore, as in all plants, the spores are haploid. The spore capsule opens when the spores are mature, and the spores are carried away by wind or water. When a moss spore settles to the ground, it germinates and grows into a “leafy” green gametophyt ...
... Spores form by meiosis inside the spore capsule. Therefore, as in all plants, the spores are haploid. The spore capsule opens when the spores are mature, and the spores are carried away by wind or water. When a moss spore settles to the ground, it germinates and grows into a “leafy” green gametophyt ...
Psychological and Physiological Adaptations to Sperm Competition
... human evolutionary history. Smith suggested that facultative polyandry (i.e., female sexual infidelity) would have been the most common reason for the simultaneous presence of live ...
... human evolutionary history. Smith suggested that facultative polyandry (i.e., female sexual infidelity) would have been the most common reason for the simultaneous presence of live ...
Psychological and Physiological Adaptations to Sperm
... human evolutionary history. Smith suggested that facultative polyandry (i.e., female sexual infidelity) would have been the most common reason for the simultaneous presence of live ...
... human evolutionary history. Smith suggested that facultative polyandry (i.e., female sexual infidelity) would have been the most common reason for the simultaneous presence of live ...
Liang, O`Halloran and Tan Metaphor and Symbol
... implied basis for the association for the purpose of investigating the particular socio-cultural values and ideologies reflected in sex education books in Mainland China. (c) Cross-experience metaphor: In representing the physiological activity of sexual intercourse, a unique type of metaphor is ide ...
... implied basis for the association for the purpose of investigating the particular socio-cultural values and ideologies reflected in sex education books in Mainland China. (c) Cross-experience metaphor: In representing the physiological activity of sexual intercourse, a unique type of metaphor is ide ...
In a single male ejaculation
... Areas of focus: Form Follows Function concept spread throughout. Levels of biological organization, cell basics, cells of the body, tissues, organs, organ systems, homeostasis, functions of the skeletal system, categories of bones, marrow, bones of the human body, bone disease, types of joints, mu ...
... Areas of focus: Form Follows Function concept spread throughout. Levels of biological organization, cell basics, cells of the body, tissues, organs, organ systems, homeostasis, functions of the skeletal system, categories of bones, marrow, bones of the human body, bone disease, types of joints, mu ...
Part_12_Reproductive_System
... Areas of focus: Form Follows Function concept spread throughout. Levels of biological organization, cell basics, cells of the body, tissues, organs, organ systems, homeostasis, functions of the skeletal system, categories of bones, marrow, bones of the human body, bone disease, types of joints, mu ...
... Areas of focus: Form Follows Function concept spread throughout. Levels of biological organization, cell basics, cells of the body, tissues, organs, organ systems, homeostasis, functions of the skeletal system, categories of bones, marrow, bones of the human body, bone disease, types of joints, mu ...
- ISpatula
... 31) Similar to cacti and euphorbs, conifers often have leaves that are modified into a needle -like shape–an adaptation to arid environments. Yet, the taiga bioprovince of the northern hemisphere and the slopes of mountain ranges receive plenty of annual precipitation and have dense conifer forests ...
... 31) Similar to cacti and euphorbs, conifers often have leaves that are modified into a needle -like shape–an adaptation to arid environments. Yet, the taiga bioprovince of the northern hemisphere and the slopes of mountain ranges receive plenty of annual precipitation and have dense conifer forests ...
HUMAN SPERM COMPETITION
... matings), rape, and female infidelity are contexts that can place the sperm of different men into competition. Prostitution and communal sex are relatively rare and probably did not represent a recurrent context over the evolutionary history of humans in which sperm competition could act as a select ...
... matings), rape, and female infidelity are contexts that can place the sperm of different men into competition. Prostitution and communal sex are relatively rare and probably did not represent a recurrent context over the evolutionary history of humans in which sperm competition could act as a select ...
KS3 Bio 7B Reproduction 116marks 4Teachers
... Fill the two gaps in the sentences below. A fertilised egg divides into a tiny ball of cells called an embryo. The embryo attaches to the lining of the uterus. Here the embryo grows to become an unborn baby, called a ...................................... . It takes about ........................... ...
... Fill the two gaps in the sentences below. A fertilised egg divides into a tiny ball of cells called an embryo. The embryo attaches to the lining of the uterus. Here the embryo grows to become an unborn baby, called a ...................................... . It takes about ........................... ...
File - THE ISLAM SHOW
... The functioning of a person's hormonal system generally begins when he is still in his mother's womb and continues right up until his death. Reproductive glands start to function as a result of the effect of hormones too. But unlike other parts of the body, the secretion of hormones relevant to the ...
... The functioning of a person's hormonal system generally begins when he is still in his mother's womb and continues right up until his death. Reproductive glands start to function as a result of the effect of hormones too. But unlike other parts of the body, the secretion of hormones relevant to the ...
Sperm competition and sperm cooperation: the potential role of
... typical of the nucleus of normally functional cells) by transition proteins and protamines during spermatogenesis (Dadoune et al. 2004) seems to suggest that gene expression in sperm is suppressed. This appears to be advantageous as the suppression of the haploid genes in sperm would avoid potential ...
... typical of the nucleus of normally functional cells) by transition proteins and protamines during spermatogenesis (Dadoune et al. 2004) seems to suggest that gene expression in sperm is suppressed. This appears to be advantageous as the suppression of the haploid genes in sperm would avoid potential ...
Toward in vitro fertilization in Brachiaria spp.
... cytoplasm and remnants of only thin pollen walls point to lethality from the beginning of the microspore stage. Germination medium on culture plates was optimized to achieve in vitro fertilization with a high percentage of growing pollen tubes. Several sucrose concentrations were tested for germinat ...
... cytoplasm and remnants of only thin pollen walls point to lethality from the beginning of the microspore stage. Germination medium on culture plates was optimized to achieve in vitro fertilization with a high percentage of growing pollen tubes. Several sucrose concentrations were tested for germinat ...
Bryophyte Gametophytes
... Life Cycles with Dominant Sporophytes • In contrast with bryophytes – Sporophytes of seedless vascular plants are the larger generation, as in the familiar leafy fern – The gametophytes are tiny plants that grow on or below the soil surface ...
... Life Cycles with Dominant Sporophytes • In contrast with bryophytes – Sporophytes of seedless vascular plants are the larger generation, as in the familiar leafy fern – The gametophytes are tiny plants that grow on or below the soil surface ...
Reproductive Physiology
... results in a zygote with too many chromosomes • Regarding the sex chromosomes, it may be ...
... results in a zygote with too many chromosomes • Regarding the sex chromosomes, it may be ...
Chapter 17
... 2. Male gametangium called the antheridium (club shaped) 3. Gametangia produced at tips of leafy gametophytes 4. Sperm are flagellated and reach archegonium by swimming in a film of water 5. Sporophyte develops in base of archegonium and grows into a foot, seta, and a capsule 6. Calyptra sits on top ...
... 2. Male gametangium called the antheridium (club shaped) 3. Gametangia produced at tips of leafy gametophytes 4. Sperm are flagellated and reach archegonium by swimming in a film of water 5. Sporophyte develops in base of archegonium and grows into a foot, seta, and a capsule 6. Calyptra sits on top ...
THE EVOLUTION OF MALE TRAITS IN SOCIAL INSECTS Jacobus J
... lifetime spermatogenesis when they reach sexual maturity (37, 61, 65) and cannot increase their supplement of sperm afterward. Male sperm limitation therefore did not evolve as a result of social fatherhood, although a further reduced time frame for mating probably reinforced selection to maintain t ...
... lifetime spermatogenesis when they reach sexual maturity (37, 61, 65) and cannot increase their supplement of sperm afterward. Male sperm limitation therefore did not evolve as a result of social fatherhood, although a further reduced time frame for mating probably reinforced selection to maintain t ...
The mating game: pollination and fertilization in flowering plants
... proteins (AGPs), abundant in stylar secretions, may provide important directional cues. The Yariv reagent, which binds AGPs, inhibits growth of lily and maize pollen, although a similar effect was not observed in all plants [35]. In Nicotiana tabacum, a transmitting tissue specific glycoprotein, TTS ...
... proteins (AGPs), abundant in stylar secretions, may provide important directional cues. The Yariv reagent, which binds AGPs, inhibits growth of lily and maize pollen, although a similar effect was not observed in all plants [35]. In Nicotiana tabacum, a transmitting tissue specific glycoprotein, TTS ...
biology1
... -A small sporophyte generation retained within or supported by the gametophyte plant is typical of Mosses Ferns Mosses and ferns Angiosperms ...
... -A small sporophyte generation retained within or supported by the gametophyte plant is typical of Mosses Ferns Mosses and ferns Angiosperms ...
Ch. 46 Lecture 46_Lecture_2014
... higher fraction of zygotes • Internal fertilization is also often associated with mechanisms to provide protection of embryos and parental care of young ...
... higher fraction of zygotes • Internal fertilization is also often associated with mechanisms to provide protection of embryos and parental care of young ...
EVOLUTION AND DIVERSITY OF GREEN AND LAND PLANTS
... the cells, acting as a sort of cellular exoskeleton. The evolu tion of a cellulosic cell wall was a preamble to the further evolution of more complex types of growth, particularly of self-supporting shoot systems. It is not clear if a cellulosic cell wall constitutes an apomorphy for the Viridiplant ...
... the cells, acting as a sort of cellular exoskeleton. The evolu tion of a cellulosic cell wall was a preamble to the further evolution of more complex types of growth, particularly of self-supporting shoot systems. It is not clear if a cellulosic cell wall constitutes an apomorphy for the Viridiplant ...
Reproduction - Male
... Prevention of bacteria and other large molecular substances from dam to young. The secretion of certain hormones; HCG (woman) and PMSG (mare), and ...
... Prevention of bacteria and other large molecular substances from dam to young. The secretion of certain hormones; HCG (woman) and PMSG (mare), and ...
reproduction - Teaching Biology Project
... Marine mammals and some fish e.g. sharks and rays also have internal fertilisation. Mating and copulation occurs. Most animals have cloaca – common opening for reproduction and egestion – during fertilisation cloacas are lined up. Male insects and mammals have a penis – organ to transfer sperm to bo ...
... Marine mammals and some fish e.g. sharks and rays also have internal fertilisation. Mating and copulation occurs. Most animals have cloaca – common opening for reproduction and egestion – during fertilisation cloacas are lined up. Male insects and mammals have a penis – organ to transfer sperm to bo ...
REPRODUCTION - Teaching Biology Project
... Marine mammals and some fish e.g. sharks and rays also have internal fertilisation. Mating and copulation occurs. Most animals have cloaca – common opening for reproduction and egestion – during fertilisation cloacas are lined up. Male insects and mammals have a penis – organ to transfer sperm to bo ...
... Marine mammals and some fish e.g. sharks and rays also have internal fertilisation. Mating and copulation occurs. Most animals have cloaca – common opening for reproduction and egestion – during fertilisation cloacas are lined up. Male insects and mammals have a penis – organ to transfer sperm to bo ...
ch 29 plant diversity
... Alternation of Generations and Multicellular, Dependent Embryos • Plants alternate between two multicellular stages, a reproductive cycle called alternation of generations • The gametophyte is haploid and produces haploid gametes by mitosis • Fusion of the gametes gives rise to the diploid sporophy ...
... Alternation of Generations and Multicellular, Dependent Embryos • Plants alternate between two multicellular stages, a reproductive cycle called alternation of generations • The gametophyte is haploid and produces haploid gametes by mitosis • Fusion of the gametes gives rise to the diploid sporophy ...
Fertilisation
Fertilisation (also known as conception, fecundation and syngamy) is the fusion of gametes to initiate the development of a new individual organism. In animals, the process involves the fusion of an ovum with a sperm, which first creates a zygote and then leads to the development of an embryo. Depending on the animal species, the process can occur within the body of the female in internal fertilisation, or outside (external fertilisation). The cycle of fertilisation and development of new individuals is called sexual reproduction.