2. Nature of the Reproductive Process
Modes of Reproduction
- Asexual - one parent, no special reproductive organs or cells. Offspring are
genetic clones
- Sexual - generally two parents, uses gametes, offspring are genetically
distinct
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3. Nature of the Reproductive Process
Modes of Reproduction
- Asexual Reproduction
- Where found? Bacteria, unicellular
eukaryotes, many invertebrate phyla
- Modes of asexual reproductions
- Fission - binary or multiple
(schizogony). Equal division
- Budding - unequal division
- Gemmulation - new individual
from capsule
- Fragmentation - breaking in two
(or more)
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4. Nature of the Reproductive Process
Modes of Reproduction
- Asexual Reproduction
- Where found? Bacteria, unicellular
eukaryotes, many invertebrate phyla
- Modes of asexual reproductions
- Fission - binary or multiple
(schizogony). Equal division
- Budding - unequal division
- Gemmulation - new individual
from capsule
- Fragmentation - breaking in two
(or more)
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5. Nature of the Reproductive Process
Modes of Reproduction
- Asexual Reproduction
- Where found? Bacteria, unicellular
eukaryotes, many invertebrate phyla
- Modes of asexual reproductions
- Fission - binary or multiple
(schizogony). Equal division
- Budding - unequal division
- Gemmulation - new individual
from capsule
- Fragmentation - breaking in two
(or more)
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6. Nature of the Reproductive Process
Modes of Reproduction
- Asexual Reproduction
- Where found? Bacteria, unicellular
eukaryotes, many invertebrate phyla
- Modes of asexual reproductions
- Fission - binary or multiple
(schizogony). Equal division
- Budding - unequal division
- Gemmulation - new individual
from capsule
- Fragmentation - breaking in two
(or more)
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7. Nature of the Reproductive Process
Modes of Reproduction
- Sexual Reproduction
- Where found? All other animals
- Bisexual reproduction,
hermaphroditism, parthenogenesis
- Bisexual most common
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8. Nature of the Reproductive Process
Modes of Reproduction
- Bisexual reproduction
- Gamete characteristics
- Ovum (egg) - large, nonmotile,
few
- Spermatozoon (sperm) - small,
motile, many
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9. Nature of the Reproductive Process
Modes of Reproduction
- Bisexual reproduction
- Gametogenesis - production of gametes
via meiosis
- Oogenesis - ova
- Spermatogenesis - sperm
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10. Nature of the Reproductive Process
Modes of Reproduction
- Bisexual reproduction
- Spermatogenesis
- Walls of seminiferous tubules
- Sertoli cells
- Vasa efferentia
- Epididymis
- Vas deferens
- Seminal vesicles (x2)
- Prostate gland
- Bulbourethral gland
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11. Nature of the Reproductive Process
Modes of Reproduction
- Bisexual reproduction
- Oogenesis
- Within ovary
- Meiosis I and II
- Ovulated
- Enters fallopian tube
- Fertilization here
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12. Nature of the Reproductive Process
Modes of Reproduction
- Dioecious - species with separate
sexes
- Monoecious - both sexes in same
individual
- Hermaphrodite
- Many practice cross-fertilization
(reciprocal fertilization)
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13. Nature of the Reproductive Process
Modes of Reproduction
- Parthenogenesis
- Development of an embryo from
unfertilized egg
- Still sexual reproduction - uses
gametes
- Haplodiploidy - unfertilized eggs are
males, fertilized are females
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14. Nature of the Reproductive Process
Why has sexual reproduction evolved
and been favored?
- Costs
- Expensive (time and energy)
- Grow traits
- Find mates
- Only pass along half of genes
- Asexual species avoid all of these
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15. Nature of the Reproductive Process
Why has sexual reproduction evolved
and been favored?
- Costs
- Expensive (time and energy)
- Grow traits
- Find mates
- Only pass along half of genes
- Asexual species avoid all of these
Diversity
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16. Reproductive Patterns
Oviparous - producing young by means of hatching eggs after they are laid by the
parent
Ovoviviparous - producing young by means of hatching eggs within the parent
Viviparous - producing young by live birth
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