Animal Reproduction: Sexual and Asexual

Many species have evolved intricate reproductive strategies. Consider a hypothetical scenario where a novel species alternates between sexual reproduction during periods of environmental stability and parthenogenesis when resources become scarce. Which selective advantage would MOST likely drive this reproductive plasticity?

A newly discovered species of deep-sea anglerfish exhibits a unique form of reproduction. The male, significantly smaller than the female, fuses permanently to her body, effectively becoming a parasitic appendage that solely provides sperm. Which evolutionary constraint MOST likely drove the development of this extreme sexual dimorphism and reproductive strategy?

A population of intertidal snails is observed to transition from separate sexes to hermaphroditism over several generations following a catastrophic oil spill. Under the assumption that this transition maximizes inclusive fitness, what selective pressure MOST likely underlies this evolutionary shift?

Consider a scenario where a population of cyclical parthenogens experiences a prolonged period of stable environmental conditions. What evolutionary trend would be MOST likely to emerge over many generations, assuming the maintenance of genetic variation is selectively advantageous?

A hypothetical species of social insect exhibits haplodiploidy, and queens can control the sex ratio of their offspring. If a new, highly virulent pathogen specifically targets males, what adaptive response would maximize the queen's inclusive fitness in the short term?

A species of coral exhibits both sexual and asexual reproduction. Under what environmental conditions would sexual reproduction be MOST favored over asexual reproduction?

In certain species of bees, wasps, and ants, parthenogenesis is a natural form of reproduction. Which of the following is MOST accurate regarding the genetic diversity of offspring produced via parthenogenesis, compared to sexual reproduction?

Hermaphroditism is an adaptation seen in various animal species, particularly those that are sessile or parasitic. What is the MOST significant evolutionary advantage of hermaphroditism in such species?

A species of flatworm reproduces through fragmentation and regeneration. If a flatworm is divided into multiple pieces, each piece can regenerate into a complete individual. What cellular process is MOST critical for this regeneration?

In the context of animal reproduction, what is the MOST accurate definition of 'inclusive fitness'?

Several mechanisms of asexual reproduction exist in the animal kingdom, each with distinct implications for genetic diversity. If a specific species relies solely on mitotic cell division for asexual reproduction, what is the MOST likely outcome regarding the genetic makeup of the offspring?

A population of aphids exhibits cyclical parthenogenesis, alternating between asexual and sexual reproduction depending on environmental cues. Predict the MOST likely consequence if this aphid population is subjected to a long-term, stable environment with abundant resources.

Consider a dioecious species where individuals can change their sex during their lifetime. Under what scenario would protogyny (female-to-male sex change) be MOST advantageous?

Certain species of whiptail lizards consist entirely of females and reproduce through parthenogenesis. Given that sexual reproduction is generally more common, which of the following is the MOST likely evolutionary explanation for this unusual reproductive strategy?

Fragmentation and regeneration are forms of asexual reproduction observed in certain animal species. What is the MOST significant limitation of this reproductive strategy compared to sexual reproduction, regarding adaptation to rapidly changing environments?

Hermaphroditic organisms possess both male and female reproductive organs. Which ecological circumstance would MOST strongly select for hermaphroditism in a species?

Many animal species exhibit variations in their reproductive strategies. What fundamental factor underlies the evolutionary selection of a particular reproductive mode (asexual vs. sexual) in a given species?

Consider a population of lizards in which some individuals reproduce sexually and others reproduce asexually through parthenogenesis. A novel, highly virulent pathogen emerges that targets only individuals with a specific MHC (major histocompatibility complex) allele. Which reproductive strategy will MOST likely confer a selective advantage during this epidemic?

A species of sessile marine invertebrate releases both sperm and eggs into the water column for external fertilization. What evolutionary pressure would MOST likely lead to the development of self-fertilization in this species?

In a hypothetical population of birds, some females consistently lay larger clutches of eggs than others. However, there is a trade-off: larger clutches result in reduced parental care per offspring, leading to lower survival rates. Assuming that clutch size is heritable, under what environmental condition would natural selection MOST likely favor females laying smaller clutches?

A species of parasitic wasp reproduces by laying its eggs inside the larvae of other insects. The wasp larvae then consume the host larva from the inside out. What evolutionary pressure would MOST likely lead to the development of polyembryony (where a single egg divides into multiple genetically identical embryos) in this wasp species?

In the marine environment, broadcast spawning is a common reproductive strategy where many individuals release eggs and sperm simultaneously into the water. What factor is MOST critical for successful fertilization in species employing this method?

Some animal species can change their sex in response to environmental conditions. In a population of sequential hermaphrodites, what critical factor determines whether an individual switches from female to male (protogyny) or male to female (protandry)?

Consider a species where asexual reproduction primarily occurs through parthenogenesis. What evolutionary constraint is MOST likely to limit the long-term survival and adaptability of this species?

Which of the following scenarios BEST illustrates a trade-off between reproductive rate and offspring survival?

Fragmentation and regeneration, while effective for asexual reproduction, are NOT universally applicable across the animal kingdom. Which biological constraint MOST limits the evolution of this reproductive strategy in larger, more complex animals?

What is the MOST significant evolutionary advantage of sexual reproduction compared to asexual reproduction in the context of a rapidly evolving parasite?

A species of bird colonizes a remote island with limited resources. The population initially consists of a few individuals with varying clutch sizes. Over time, what evolutionary outcome is MOST likely regarding clutch size, assuming that offspring survival is strongly dependent on resource availability?

In a population of hermaphroditic earthworms, what evolutionary mechanism would MOST likely prevent self-fertilization and promote outcrossing (mating with another individual)?

Consider a population of starfish that reproduce through fragmentation. If a major oil spill contaminates their habitat, what is the MOST likely long-term consequence for the genetic diversity of the population?

In a social insect colony with a haplodiploid genetic system, what is the coefficient of relatedness (r) between a worker bee and her sister?

A novel species of fungus is discovered that infects and sterilizes male insects, causing them to behave like females and attract other males, which then become infected. What evolutionary outcome is MOST likely in the long term for BOTH the insect and the fungus populations?

Consider a species that exhibits protandry. Under what ecological condition would this reproductive strategy be MOST advantageous?

What is the PRIMARY selective pressure that favors the evolution of sexual reproduction over asexual reproduction in many organisms?

A species of deep-sea invertebrate is discovered to reproduce asexually through budding. However, the newly formed buds remain attached to the parent organism, forming large, interconnected colonies. What is the MOST likely selective advantage of this colonial lifestyle in the deep sea?

In species that reproduce via external fertilization, what cue is MOST critical to synchronize the release of gametes to maximize fertilization success?