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In anisogamous reproduction, the female gamete is smaller and motile, while the male gamete is larger and immotile.
Answer: False
In anisogamous reproduction, the female gamete is larger and typically immotile, while the male gamete is smaller and motile.
Oogamy is a form of anisogamy where the female gamete is significantly larger than the male gamete.
Answer: True
Oogamy is indeed a form of anisogamy characterized by a large, immotile female gamete (ovum) and a small, motile male gamete (sperm).
Anisogamy is theorized to have evolved because larger gametes offer better survival chances, and smaller gametes are more mobile.
Answer: True
The evolution of anisogamy is theorized to provide advantages in both gamete survival (larger gametes) and fertilization efficiency (smaller, motile gametes).
Anisogamy has evolved only once in the history of life from isogamy.
Answer: False
Anisogamy appears to have evolved multiple times independently from isogamy.
Sexual reproduction involves a single parent producing genetically identical offspring.
Answer: False
Sexual reproduction typically involves two parents and results in genetically diverse offspring, unlike asexual reproduction.
The term "heterogamous" describes reproductive systems where gametes are identical in size and form.
Answer: False
Heterogamous reproduction refers to systems where gametes differ in size or form, such as anisogamy and oogamy.
The primary function of gametes is to fuse during fertilization to initiate the development of a new organism.
Answer: True
Gametes are specialized sex cells that fuse during fertilization to form a zygote, initiating new organism development.
An anisogamous reproduction system involves gametes of similar size and form.
Answer: False
Anisogamous systems are characterized by gametes that differ in size, with the female gamete being larger.
Heterogamous reproduction systems are characterized by gametes that differ in size or form.
Answer: True
Heterogamy signifies reproductive systems where gametes exhibit differences in size or morphology.
How do gametes typically differ in anisogamous reproduction?
Answer: The female gamete is larger and typically immotile; the male gamete is smaller and motile.
In anisogamy, the female gamete (ovum) is larger and typically immotile, while the male gamete (sperm) is smaller and motile.
What is the main distinction between sexual reproduction and asexual reproduction?
Answer: Sexual reproduction leads to genetic diversity; asexual reproduction does not.
The primary distinction is that sexual reproduction involves gamete fusion and generates genetic diversity, whereas asexual reproduction involves a single parent and produces genetically identical offspring.
What is the significance of the term "heterogamous" in reproduction?
Answer: It refers to systems where gametes differ in size or form.
The term "heterogamous" signifies reproductive systems where the gametes involved exhibit differences in size or form.
The biological definition of a female organism is based on its capacity to produce ova, the larger gametes involved in sexual reproduction.
Answer: True
The biological definition of a female organism centers on its ability to produce ova, which are the larger gametes essential for sexual reproduction.
Mammary glands are a defining characteristic of mammals, typically more developed in males than females.
Answer: False
Mammary glands are a defining characteristic of mammals, typically more developed in females for milk production.
All mammalian females give birth to live young, with no exceptions.
Answer: False
Monotreme mammals, such as the platypus, are an exception as their females lay eggs.
Oogenesis is the process of producing male gametes (sperm).
Answer: False
Oogenesis is the biological process of producing ova (egg cells), not sperm.
Mammary glands are significant because they produce milk to nourish offspring, a function typically more developed in females.
Answer: True
Mammary glands are a key mammalian trait for nourishing young, and they are generally more developed in females.
The primary function of ova is fertilization by male gametes to start new organism development.
Answer: True
Ova serve as the female gametes that are fertilized by male gametes to initiate the development of a new organism.
Feminization refers to the development of male characteristics in an organism.
Answer: False
Feminization denotes the development of female characteristics or a transition towards a female state.
Which of the following best defines a female organism in biological terms?
Answer: An organism capable of producing ova, the larger gametes.
The fundamental biological definition of a female organism is its capacity to produce ova, the larger gametes involved in sexual reproduction.
What key characteristic defines female mammals?
Answer: The presence of mammary glands.
The presence of mammary glands, used for nourishing offspring, is a defining characteristic of female mammals.
Which group of mammals lays eggs instead of giving birth to live young?
Answer: Monotremes
Monotremes, such as the platypus and echidnas, are mammals whose females lay eggs.
What does the term "oogenesis" refer to?
Answer: The biological process of producing ova (egg cells).
Oogenesis is the biological process by which ova, or egg cells, are produced within the female reproductive system.
What is the primary function of ova in sexual reproduction?
Answer: To be fertilized by male gametes (sperm).
The primary function of ova is to undergo fertilization by male gametes (sperm) to initiate the development of a new organism.
In most mammals, females possess one X chromosome and one Y chromosome (XY), while males possess two X chromosomes (XX).
Answer: False
In most mammals, females are XX and males are XY.
In placental mammals, one of the female's two X chromosomes is randomly inactivated in each cell.
Answer: True
This process, known as X-inactivation, occurs randomly in placental mammals to regulate gene dosage from the two X chromosomes.
Birds and some reptiles utilize the XY sex-determination system, where females are XY and males are XX.
Answer: False
Birds and some reptiles utilize the ZW system, where females are ZW and males are ZZ, the reverse of the mammalian XY system.
Alfred Jost's experiments in the 1940s suggested that the female is the default sex in mammalian sexual determination.
Answer: True
Jost's experiments indicated that mammalian development defaults to female in the absence of testicular hormones, though recent studies have begun to question this.
The sex of an organism can only be determined by its genetic makeup.
Answer: False
Sex determination can be influenced by genetic factors, environmental conditions, or natural changes during an organism's life.
In the ZW sex-determination system, females possess two Z chromosomes (ZZ).
Answer: False
In the ZW system, males are ZZ, and females are ZW.
Temperature-dependent sex determination is observed in species like certain fish.
Answer: False
Temperature-dependent sex determination is observed in species such as crocodilians, not typically fish.
*Wolbachia* bacteria can influence sex determination in some arthropods by affecting female sexual viability.
Answer: True
*Wolbachia* can be crucial for female sexual viability and influence sex determination in certain arthropod species.
The concept of "sex as a biological variable" acknowledges that sex influences biological processes and research outcomes.
Answer: True
Recognizing sex as a biological variable means understanding its impact on biological processes and research findings.
In the ZW sex-determination system, females are ZZ and males are ZW.
Answer: False
In the ZW system, females are ZW and males are ZZ.
The Y chromosome in mammals primarily determines femaleness.
Answer: False
The Y chromosome in mammals primarily determines maleness, not femaleness.
In some species, like certain gobies, sex determination can change naturally during the organism's life.
Answer: True
Certain species, such as some gobies, exhibit sequential hermaphroditism, where sex can change naturally during their lifespan in response to environmental or social cues.
The X chromosome in female mammals carries essential genes for development and is typically inactivated in all cells.
Answer: False
While the X chromosome carries essential genes, it is typically inactivated randomly in *most* cells, not all cells, in female mammals.
How does the typical chromosomal makeup of female mammals differ from males?
Answer: Females are XX; Males are XY.
Typically, female mammals possess two X chromosomes (XX), while males possess one X and one Y chromosome (XY).
What occurs to one of the X chromosomes in female placental mammals?
Answer: It is randomly inactivated in each cell.
In placental mammals, one of the two X chromosomes in females undergoes random inactivation in most cells.
In birds and some reptiles, which sex is typically heterozygous for sex chromosomes, and what are those chromosomes?
Answer: Female, carrying ZW chromosomes.
In birds and some reptiles, the female sex is typically heterozygous, possessing ZW sex chromosomes.
What did Alfred Jost's experiments in the 1940s suggest about mammalian sex determination?
Answer: The female is the default sex.
Alfred Jost's experiments suggested that mammalian sexual development defaults to female in the absence of specific male hormonal influences.
Besides genetics, what other factors can determine an organism's sex?
Answer: Genetic factors, environmental conditions, or natural changes during life.
An organism's sex can be determined by genetic makeup, environmental factors, or through natural changes occurring during its life cycle.
In the ZW sex-determination system, what is the chromosomal makeup of males?
Answer: ZZ
In the ZW sex-determination system, males possess two Z chromosomes (ZZ).
How can environmental factors influence sex determination, as seen in crocodilians?
Answer: The temperature at which eggs are incubated.
In crocodilians, the temperature during egg incubation is a critical environmental factor that determines the sex of the offspring.
What role can *Wolbachia* bacteria play in some arthropods?
Answer: They are required for female sexual viability and influence sex determination.
*Wolbachia* bacteria are essential for female sexual viability and influence sex determination in numerous arthropod species.
The concept of "sex as a biological variable" emphasizes that:
Answer: Biological sex influences biological processes and research outcomes.
Acknowledging "sex as a biological variable" highlights its influence on biological processes, health outcomes, and research findings.
Species divided into distinct females and males are classified as dioecious in animals and gonochoric in seed plants.
Answer: False
Species with distinct males and females are classified as gonochoric in animals and dioecious in seed plants and dioicous in cryptogams.
Gynodioecy is a sexual system characterized by the coexistence of male individuals and hermaphrodites.
Answer: False
Gynodioecy is characterized by the coexistence of female individuals and hermaphrodites within a species.
Trioecy involves the coexistence of female individuals, males, and hermaphrodites within the same species.
Answer: True
Trioecy describes a sexual system where females, males, and hermaphrodites coexist within the same species.
Dioecy describes species where individuals are either male or female, whereas gynodioecy involves females and hermaphrodites.
Answer: True
Dioecy refers to species with separate male and female individuals, while gynodioecy involves females and hermaphrodites.
Which of the following describes the sexual system known as dioecy?
Answer: Individuals are either male or female.
Dioecy is a sexual system where individuals within a species are distinctly either male or female.
What is trioecy?
Answer: A system where females coexist with both males and hermaphrodites.
Trioecy is a sexual system characterized by the coexistence of female individuals, males, and hermaphrodites within the same species.
The symbol ♀, representing the female sex, is believed by modern scholars to originate from a depiction of Venus's mirror.
Answer: False
While one historical speculation links the female symbol (♀) to Venus's mirror, modern scholarly consensus suggests it originates from contractions in Greek script of planetary names.
The English word "female" was originally derived from the Latin word *masculus*, meaning "male."
Answer: False
The English word "female" originates from the Latin *femella*, meaning "woman," not from *masculus*.
The term "female" has been used as both a noun and an adjective in English since the 14th century, initially referring only to non-human organisms.
Answer: False
The term "female" has been used as a noun and adjective since the 14th century, initially referring to humans, with its application expanding to non-human organisms later.
By the late 19th century, using "female" as a noun to refer to humans became widely accepted as the most respectful term.
Answer: False
By the late 19th century, the usage of "female" as a noun for humans began to be considered disparaging, partly due to its association with non-human animals.
In contemporary 21st-century usage, the noun "female" is primarily used for humans in informal social contexts.
Answer: False
In the 21st century, the noun "female" is primarily used for non-human animals or in impersonal technical contexts for humans, not informal social contexts.
The adjective "female" is rarely used today, even when the sex of a person is relevant to the context.
Answer: False
The adjective "female" remains commonly used when sex is relevant to the context, such as in discussions of "female athletes."
Biological sex and gender identity are considered synonymous concepts in human biology.
Answer: False
Biological sex and gender identity are distinct concepts; sex refers to biological characteristics, while gender encompasses identity and expression.
In connectors and fasteners, the "female" part is the one that inserts into another.
Answer: False
In connectors and fasteners, the "female" component is the socket or receptacle designed to receive the "male" part.
In humans, the term "female" exclusively refers to biological sex and never relates to gender identity.
Answer: False
While "female" can refer to biological sex, it can also be used socially, and biological sex is distinct from gender identity.
The spelling of "female" was changed in the late 14th century to match the spelling of "male" for etymological reasons.
Answer: False
The spelling change in the late 14th century was to parallel "male," not due to etymological reasons.
The Venus symbol (♀) is universally recognized in biology to represent the male sex.
Answer: False
The Venus symbol (♀) universally represents the female sex in biology.
The term "female" in humans relates solely to biological sex and has no connection to gender identity.
Answer: False
While "female" can denote biological sex, it is also used socially, and biological sex is distinct from gender identity.
The origin of the female symbol (♀) is definitively linked to the Roman goddess Venus's mirror.
Answer: False
Modern scholarship suggests the female symbol (♀) originates from Greek script contractions, not definitively from Venus's mirror.
What is the origin of the biological symbol for the female sex (♀)?
Answer: It is derived from contractions in Greek script of planetary names.
Modern scholarship indicates the biological symbol for the female sex (♀) originates from Greek script contractions of planetary names associated with Venus.
The word "female" in English evolved from Latin. What was its original Latin root, and how did its spelling change?
Answer: From *femina*, meaning 'woman'; spelling changed to resemble 'male'.
The English word "female" derives from the Latin *femina* ('woman'), with its spelling later altered in the 14th century to resemble "male."
When did the term "female" begin to be used for non-human organisms?
Answer: In the 15th century, approximately a century after its initial use for humans.
The term "female" expanded from its initial 14th-century human-specific usage to include non-human organisms approximately a century later, in the 15th century.
How did the perception of "female" as a noun change around the late 19th century?
Answer: It started being considered disparaging, partly due to its use for animals.
By the late 19th century, the noun "female" began to be perceived as potentially disparaging, partly because its usage extended to non-human animals.
In the 21st century, where is the noun "female" primarily used?
Answer: Mainly to describe non-human animals and in impersonal technical contexts for humans.
Contemporary usage of the noun "female" predominantly applies to non-human animals or in impersonal, technical contexts for humans.
When is the adjective "female" still commonly used today?
Answer: When the sex of a person is relevant to the context, like "female athletes."
The adjective "female" remains common when sex is contextually relevant, such as in "female athletes" or when distinguishing between sexes.
In human biology, what is the relationship between "female" (biological sex) and gender identity?
Answer: They are distinct concepts, though "female" can be used socially.
Biological sex ("female") and gender identity are distinct concepts, although the term "female" can also be applied socially.
The primary evolutionary question regarding females relates to understanding the initial evolution of males from asexual reproduction.
Answer: True
The evolution of sexual reproduction, particularly the emergence of males, is a central question when considering the evolutionary trajectory of females.
Producing large amounts of pollen is considered a cost associated with being female in plants.
Answer: False
Producing large amounts of pollen is identified as a cost associated with being male in plants.
The "lock-and-key" mechanism is one hypothesis explaining the evolution of female genitalia, suggesting specific physical fits.
Answer: True
The "lock-and-key" mechanism posits that female genitalia evolved to ensure specific physical compatibility with male reproductive structures.
The evolutionary advantage of smaller, motile gametes (sperm) is their increased ability to locate female gametes.
Answer: True
Smaller, motile gametes (sperm) enhance fertilization efficiency by increasing their capacity to find and reach larger, less mobile female gametes (ova).
What is a potential cost associated with being male in sexually reproducing species?
Answer: Developing elaborate traits for sexual display.
Costs for males can include investing resources in traits for sexual display, such as elaborate plumage or antlers, to attract mates.
The evolution of anisogamy (different-sized gametes) is theorized to be advantageous because:
Answer: Larger gametes improve survival chances, and smaller gametes increase fertilization efficiency.
Anisogamy is theorized to be advantageous as larger gametes enhance survival prospects, while smaller, motile gametes improve fertilization efficiency.
How many times has anisogamy independently evolved, according to the source?
Answer: Multiple times independently.
The source indicates that anisogamy has evolved independently on multiple occasions throughout the history of life.
Which hypothesis suggests female genitalia evolved due to specific physical fits between male and female reproductive structures?
Answer: Lock-and-key mechanism
The "lock-and-key" mechanism hypothesis proposes that female genitalia evolved based on specific physical compatibility requirements with male reproductive organs.