Reproduction

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Reproduction

• 1. Asexual- single parent, genetically
• identical offspring
• 2. Sexual- two parents, genetically diverse
  offspring

2
Genetic Diversity

• 1. New gene combination, genotypes
• 2. May result in new phenotypes
• 3. May increase survival reproduction rates

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Asexual Plants

• 1. Almost all plants capable
• 2. Runners- modified above ground stem
• 3. Rhizomes- modified underground stem
• 4. Tubers- modified underground storage stem with
  lateral buds

4
Sexual Plants

• 1. Alternation of generations
• 2. General
• 3. Example

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General, Alt of Gen
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Fern Gametophyte
Archegonium
Antheridium
Dave Emmitt, CCC
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Pine, Alt of Gen
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Asexual Animals

• 1. Budding- sponges cnidarians, miniature
  version of animal grows on adult. When large
  enough, breaks off

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Asexual Animals

• 2. Regeneration- some echinoderms, starfish,
  complete new individual from any segment with
  center present

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Asexual Animals

• 3. Fission- corals, flatworms, annelids, new
  individuals from fission of adult

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Asexual Animals

• 3. Parthenogenesis
• a. Eggs develop without
• fertilization
• b. Male honey bees, haploid
• c. Some fish lizards, diploid

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Sexual Animals

• 1. Union of egg sperm cell, syngamy, external
  internal fertilization
• 2. Monoecious- earthworms, many snails, male
  female organs in single organism but cross
  fertilize
• 3. Dioecious- separate male female organisms

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Spermatophore

• 1. Sperm packet
• 2. Placed on the ground, female picks up, if she
  finds it, mites spiders
• 3. Placed on the female, crayfish
• 4. Placed in the female, squid

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Developmental Stages

• 1. Zygote- fertilized egg
• 2. Embryo- cleavage, gastrulation, organogenesis
• 3. Fetus- adult appearance

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Embryo

• 1. Morula
• 2. Blastula
• 3. Gastrula
• 4. Organogenesis

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Morula

• 1. Solid ball of undifferentiated, small cells
• 2. About same size as zygote
• 3. Cleavage- division of fertilized egg with no
  increase in size

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Blastula

• 1. Blastocoel- cavity that develops within the
  cell ball
• 2. About 7 days in Homo sapiens
• 3. Blastocyste

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Gastrula

• 1. Cells invaginate into blastocoel forming
  archenteron
• 2. Blastopore- opening formed by invagination
• 3. Cell differentiation- endoderm, ectoderm,
  mesoderm
• 4. About 14 days in Homo sapiens

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Organogenesis

• 1. Ectoderm, mesoderm, endoderm rearrange
  develop into organs of adult organism
• 2. Occurs by induction
• 3. Late embryonic stage, 21 days in Homo sapiens

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Induction

• 1. During gastrulation
• 2. Fate of embryonic cells determined by chemical
  messagers produced by gastrula cells
• 3. Chemical messengers control genetic
  expression, switch genes of embryonic cells off

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Cell Layer Fate

• 1. Ectoderm
• 2. Mesoderm
• 3. Endoderm

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Ectoderm

• 1. Epidermis of skin, lining of mouth nose,
  skin glands (sweat, sebaceous, mammary), nervous
  system, eye lens, inner ear

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Mesoderm

• 1. Dermis of skin, muscle, skeleton, circulatory,
  gonads, kidneys, outer layers of digestive
  respiratory tracts

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Endoderm

• 1. inner lining of digestive respiratory
  tracts, liver, pancreas

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