Human Reproduction Text

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Human Reproduction Text
2013-01-16 22:24:54
BIO 220

Chapter 46.1 and 46.2
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  1. In some species, individuals __  during their lifetime; in other species, like sea slugs, an individual is both __ and __.
    • change their sex
    • male and female
  2. Other species, like bees, only contain few individuals who can __.
    A population outlives its members only by __, the generation of new individuals from existing ones
    • reproduce
    • reproduction

  3. a.      Two modes of animal reproduction—__and __

                                                                  i.      In sexual: __         
    a.      Female gamete: __
    b.      Male gamete: __
    • sexual
    • asexual
    • fusion of haploid gametes-->diploid zygote, which gives rise to gametes by meiosis
    • egg= large, nonmotile cell
    • sperm= smaller, motile cell

  4.                                                               i.      Asexual reproduction: __
    1.      Reproduction relies entirely on __ cell division
    b.      Majority of animals carry out __, but some have __like the __and __
    • generation of new individuals without the fusion of egg and sperm
    • mitotic
    • sexual
    • asexual
    • rotifer
    • whiptail lizard

  5. I.                   Mechanisms of Asexual Reproduction
    a.      Several among invertebrates
                                                                  i.      Fission: __
                                                                ii.      Budding: __
                                                              iii.      Gemmules: __
                                                              iv.      Two-step processes
    1.      __
    a.      If more than one piece grows and develops into a complete animal--> __
    • separation of parent organism into two individuals of approx. equal size
    • new individuals arise from outgrowths of existing ones
    • Release of specialized group of cells that grow into new individuals (sponges)
    • 1.      Fragmentation: breaking of the body into several pieces

    • 2.      Regeneration: regrowth of lost body parts
    • reproduction
    • asexual reproduction in which an egg develops without being fertilized
  6. Parthenogenesis
    • asexual reproduction in which an egg develops without being fertilized, such as in bees, wasps, and ants
    • 1.      Progeny either haploid or diploid
    • If haploid: offspring develop into adults that produce eggs and sperm without meiosis
  7. 2. Present in every__ species (Komodo dragon)
    How did they figure this out?
    •  1/1000
    • a. Females completely isolated from males of species but still produced offspring

  8. I.                   Sexual Reproduction: An Evolutionary Enigma
    a.      Sex enhances __
    b.      Case study: half females sexually reproduce; other half asexually reproduced
                                                                  i.      Explain results
    • reproductive success for survival
    • Asexual offspring increase in frequency; sexual will result in same number at each generation if one offspring a male
  9. Advantages of sexual:
    • Unique combos of parental genes formed during recombination and fertilization --> enhance reproductive success of parents when environmental factors change
    • - beneficial gene combinations through recombination speed up adaptation only if rate of beneficial mutations is high and population size is small
    • - shuffling of genes may rid population of harmful genes
  10. Advantage of asexual
    good for stable environmental due to perpetuation of successful genotypes
  11. a.      Most animals exhibit __in reproductive activity, often related to __
                                                                  i.      This helps __ -->reproduce only when energy supplied and environmental conditions favor __
    • cycles
    • changing seasons
    • conserve resources
    • survival of offspring

  12. 1.      Example of reproductive cycles: ewes: 15-17 day cycle

    a.       __( release of mature eggs) occurs at __of cycle, with the cycle occurring during __

                                                                                                                                          i.      Resulting pregnancy= 5 months; birth= __
    • Ovulation
    • midpoint
    • fall/ early winter
    • spring
  13. Reproductive cycles:

    a.       Controlled by __, which are regulated by __like temp, rainfall, lunar cycles, day length, etc.

    b.      Seasonal temperature important for reproductionà climate change may __[ex: caribou = timing of migration tied to length of daylight]
    • hormones
    • environmental cues
    • decrease reproductive success

  14. a.       Reproductive cycles also found among animals that produce both ways

                                                                  i.      Water flea produces eggs of two types, one that __; the other needs fertilization to develop; the other __

    1.      __ occurs with favorable environment and __during times of environmental stress

    a.       Switch linked to season
    • needs fertilization to develop
    • doesn't and develops by parthogenesis
    • Asexual
    • sexual
    • season
  15. Different type of __found among only __ animals.
                                                                  i.      Complex form of parthenogenesis that involves __after meiosis, producing __offspring (whiptail lizards)

    1.      No males, but __are typical of sexual species of the same genus

    a.       During breeding, one female of each mating does what?

                                                                                                                                          i.      Individual adopts female behavior prior to __, when __levels are high, then switches to male-like behavior after __, when __levels are highest

                                                                                                                                        ii.      Ovulation more likely to occur if individual is __

    1.      Isolated lizards lay less eggs than those that go through motions of sex

    a.       These views show that parthenogenetic lizards evolved from species having __and still require certain sexual stimuli for max reproductive success
    • parthogenesis
    • asexually reproducing
    • doubling of chromosomes
    • diploid
    • courtship and mating behaviors
    • pair mimics male (alternate roles during season)
    • ovulation
    • estradiol
    • ovulation
    • progesterone
    • mounted during critical time of hormone cycle
    • two sexes
  16. Reproductive cycles have a different type that is found among only __ animals.
    asexually reproducing

  17. a.       Finding partner for sex= hardà adaptations= __:

                                                                  i.      Sessile (stationary) animals (barnacles), burrowing animals (clams), etc.

    1.      Lacking locomotionà hard to find mateà __
    • blurring strict distinction between male and female
    • hermaphrodism

  18.                                                               i.      __: each individual has both male/ female reproductive systemsà since they have both parts, any two individuals can mate

    1.      each animal __

    2.      in some species, hermaphrodites can __= no partner
    • Hermaphroditism
    • donates and receives sperm during mating
    • self-fertilize

  19. a.       Different variation of sexual reproduction in wrasses

                                                                  i.      Live in __with one male and several females

    1.      When male dies, no sexual reproductionà what happens?

    a.       Advantage of this: because male defends harem against intruders, a larger size may be more important for males
    • harems
    • the largest/ oldest female wrasse changes sexes (sex reversal) and makes sperms

  20.                                                               i.      Oysters do the same: reproduce as males and then later as females, when their size is greatest

    1.      Number of gametes produced increases with __, __in this direction maximizes gamete productionà enhanced reproductive success
    • size for females more than males
    • sex reversal

  21. a.      Fertilization either __(female releases eggs into environment where male fertilizes them) or __(sperm deposited in/ near female reproductive tract)
    • external
    • internal
  22. External:

                                                                  i.      __habitat almost always required= prevents __ (many aquatic invertebrates)

    1.      __is crucial for union
    • Moist
    • gametes from drying out and allowing sperm to swim in eggs
    • Timing
  23. External fertilization:

                                                                  i.      Among some species with external, individuals clustered in same area release gametes into water at same time, called __

    1.      In some cases, a chemical signal generated by one individual in releasing gametes triggers __

    2.      In other cases, environmental cues cause __(palolo worm times spawning with season/ lunar cycle)

    a.      In spring: moon in last quarter, worms break in half, releasing tail segments engorged with sperm or eggsà rise to surface where eggs are fertilized
    • spawning
    • others to release gametes
    • whole population to release at same time

  24.                                                    External           i.      When not synchronous, specific __leading to fertilization of eggs of one female by one male may occur

    1.      “__” behavior benefits
    • mating behaviors
    • courtship
    • Allows mate choice and, by triggering release of both eggs and sperm, increases probability of successful fertilization
  25. Internal
                                                                  i.      Sperm reaches egg, even in dry environment

                                                                ii.      Requires __that leads to __, as well as sophisticated and compatible reproductive systems

    1.      Male copulatory organ __; Female reproductive tract has receptacles for __ and __ of sperm to mature eggs
    • cooperative behavior
    • copulation
    • delivers sperm
    • storage and delivery

  26. a.      __ (chemicals released by one organism that can influence physiology and behavior of other individuals of the same species)  may be used, regardless of type of fertilization

                                                                  i.      Small, __that disperse into environment and are active in tiny amounts

                                                                ii.      Function as __, enabling some female insects to be detected by males from far away
    • Pheromones
    • volatile or water-soluble molecules
    • mate attractants
  27. Internal Fertilization Pros:
    • a.      Pros: production of fewer gametes; survival of higher fraction of zygotes
  28. Internal fertilization:

                                                                  i.      Better zygote survival due to fact that eggs fertilized __are sheltered from __

    1.      associated with mechanisms that provide __and __
    • internally
    • predators
    • greater protection of embryos
    • parental care of the young
  29. Internal Fertilization:

    a.      rather than secreting a protective eggshell, some animals retain the __for a portion of its development within __
                                                                                                                                          i.      embryos of marsupials=__

                                                                                                                                        ii.      embryos of (placental) mammals= __
    • embryo
    • female reproductive tract
    • short period in uterusàembryos crawl out and complete fetal development attached to mammary gland in mom pouch
    • remain in uterus throughout where they are nourished by mom’s blood supply through the placenta (temp. organ)

  30. a.      When eggs hatch or human born, they aren’t yet capable of __

                                                                  i.      Instead adult birds feed young and mammals nurse offspring

    b.      __widespread (invertebrates do it too)

                                                                  i.      Among vertebrates, some frogs carry tadpoles in stomach until they undergo metamorphosis and hop out mouths
    • independent existence
    • Parental care

  31. a.      Sexual reproduction in animals relies on sets of cells that are precursors for __

                                                                  i.      Group of cells dedicated to this is often established very early in __and remains in __ state while plan develops

    1.      Cycles of growth and mitosis then increase (__) the number of cells that can __
    • eggs and sperm
    • formation of embryo
    • inactive
    • amplify
    • make eggs or sperm

  32. a.      In producing __from the __and making them available for __, animals employ a variety of reproductive systems

                                                                  i.      Simplest don’t __ (organs producing gametes in animals)

    1.      Palolo worms= separate sex but no distinct gonads; rather, eggs and sperm develop from __

    a.      As gametes mature, they are released from body wall and fill the __
    • gametes
    • amplified precursor cells
    • fertilization
    • discrete gonads
    • undifferentiated cells lining the coelom
    • coelom

  33. 1.      Depending on species, mature gametes may be shed through __, or swelling of mass of eggs may __
    • excretory opening
    • split portion of body open, spilling eggs into environment

  34.                                                               i.      More complex include sets of __ and __that carry, nourish, and protect gametes and sometimes the developing embryos
    accessory tubes and glands

  35. 1.      Most insect species have separate sexes with complex reproductive systems

    a.      In males: __develops in _ and pass along __to two seminal vesicles for __

                                                                                                                                          i.      During mating, sperm __ into female tract

    1.      There, __develop in pair of __and are conveyed through __to __

    a.      Eggs are fertilized in __and expelled for development __the body
    • sperm
    • testes
    • coiled duct
    • storage
    • ejaculates
    • eggs
    • ovaries
    • ducts
    • uterus
    • uterus
    • outside

  36. a.      In many insects, female reproductive system includes one or more __, sacs where sperm is stored for long periods

                                                                                                                                          i.      Because female releases male gametes from the __only in response to __, fertilization occurs under conditions suited to __
    • spermathecae
    • spermathecae
    • appropriate stimuli
    • embryonic development

  37. a.      Basic plans of all vertebrate reproductive systems are similar, but vary

                                                                  i.      Nonmammalian vertebrates

    1.      Digestive, excretory, and reproductive systems have common opening to outside (__)

  38.                                                               i.      Mammals

    1.      Lack __and have separate opening for __and __and __systems

    a.      In most vertebrates, __partly or completely divided into __chambers

    b.      In humans and other mammals that produce one or few young at a time, birds, and snakes, __is single structure

    2.      Male reproductive systems differ in __organs

    a.      Nonmammalian vertebrates, including all reptiles and amphibians, lack a well-developed __and ejaculate sperm by __
    • cloaca
    • digestive tract
    • excretory
    • reproductive
    • uterus
    • two
    • uterus
    • copulatory
    • penis
    • turning the cloaca inside out

  39. a.      Although fertilization involves union of single egg and sperm, animals may mate with more than one member of the other sex

                                                                  i.      __: sex of only two individuals ; rare among mammals

    1.      Mechanisms evolved that enhance __
    • Monogamy
    • reproductive success of a male with a particular female and diminish the chance of that female mating successfully with another partner