Animal of the Day

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Animal of the Day
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Ivory- Billed Woodpecker (Campephilus
principalis) Phylum Chordata Class
Aves  Order Piciformes Family Picidae
18-20 in. tall, 2.5 ft. wingspan
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Long considered to be extinct Last confirmed
sighting 1938, N.E. Louisiana
Habitat Bald cypress swamp
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Historically found in the Jackson Purchase of KY
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Recently Rediscovered (April 2005) in E.
Arkansas (Cache River National Wildlife Refuge)
Call Recorded
7 sightings by ornithologists
Video captured a flying bird
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CO 7
Reproduction
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Asexual Reproduction

• One parent
• Lacks specialized reproductive organs, no gametes
• No meiosis, no crossing over ? decreased genetic
  variablity
• Offspring same genotype as parent (ie. A clone)
• Many invertebrate phyla
• but not molluscs, arthropods or chordates

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Types of Asexual Reproduction
Binary Fission mitotic division of single
celled organisms eg. Protozoans Budding
unequal division of the organism, can be more
than 2 at a time. Eg. Cnidarians Gemmulation -
aggregation of pluripotent cells in a resistant
capsule eg. Poriferans Fragmentation
organism breaks into 2 or more parts each
capable of regenerating into entire organism
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Gemmule of freshwater sponge
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Sexual Reproduction

• Production of Gametes (meiosis)
• Ova large, immobile
• Sperm small, mobile
• Specialized Reproductive organs
• Two parents (usually)
• Crossing Over possible in meiosis ? genetic
  variability
• Offspring different genotype (not a clone)
• Seen in all animal phyla

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(No Transcript)
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Bisexual Reproduction
Gametes from 2 genetically distinct
individuals Dioecious separate sexes (male and
female) male spermatozoon (sperm) female
ova (eggs) Reproductive organs producing gametes
gonads primary sex organs sperm
testis egg - ovary Accessory sex organs
penis, vagina, uterine tube
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Hermaphroditism
Male and female gonads in same individual monoeci
ous Common in sessile organisms Can
self-fertilize, but usually exchange with a
partner
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Parthenogenesis virgin origin
Embryo develops from unfertilized egg or one
where nuclei fail to unite Ameiotic 2n ova
develop into offspring (clone) Meiotic haploid
ovum, may or may not require activation by
sperm diploidy restored by chromosomal
duplication or autogany (fusion of meiotic
nuclei) Haplodiploidy social insects queen
stores sperm, fertilizes some ova
(workers/queens) lays others without
fertilization (drones)
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Fig. 7.4
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Sex or No Sex?
Sexual Reproduction nearly universal among
animals Advantage recombination of genes ?
constant production of novel genotypes ?
survival in bad/ changing times Disadvantage
Energetic cost, lower population growth
rate Asexual Reproduction seen in most
groups Advantage population growth allows
exploitation of new environments ? works in
good times Disadvantage lack of genetic
variability (new genotypes) less pre-adapted to
environmental change more prone to extinction
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Sex Determination
Sex Chromosomes male XY, female
XX Y-Chromosome- 78 genes, all but 18 directly
involved with spermatogenesis (sperm
production) Single Y Chromosome- no chance for
genetic recombination
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Fig. 7.6
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Gametogenesis
Spermatogenesis testis Oogenesis - ovary
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Fig. 7.8
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Fig. 7.9
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Fig. 7.10
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Reproductive Patterns
Oviparous egg-birth eggs deposited in
environment for development fertilization may be
internal, e.g. birds or external, eg.
Amphibians, fish Ovoviviparous
egg-live-birth fertilized eggs retained in
oviduct nutrition from egg yolk, e.g. some
snakes, many inverts Viviparous
live-birth born alive, nutrition from mother,
e.g. mammals, sharks
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Fig. 7.11
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Timing of Reproduction
Aim Maximize the likelihood of offspring
survival E.g. Mammalian Reproductive
Cycles Estrous females receptive for only a
brief time heat - lack menses Menstrual
females may be receptive throughout cycle -
cyclically slough the inner endometrial lining
of the uterus (menses)
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Fig. 7.14
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Fig. 7.15
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Fig. 7.16
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Fig. 7.17
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Fig. 7.19a
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Fig. 7.19b
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Animal of the Day
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Helix aspersa- garden snail Phylum
Mollusca Class Gastropoda Order
Stylomatophora Family Helicidae
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Hermaphroditic (monoecious) copulate 2-6 hrs.
Love Darts- enhance sperm survival and inc.
fertility 116
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EscargotHelix pomantia

• 1 stick butter
• 1 ½ teasp. Minced garlic
• 2 Tbsp. Flat leaf parsley
• 1 Tbsp. Minced shallot
• 1 7oz. Can snails, rinsed
• Process butter, garlic, shallot and parsley
• Bake snails with butter mixture 10 min. at 450 F
• Serve with crusty french bread