Sexual Reproduction in Animals MaleFemale Gamete – sperm Gonad – testes Many sperm cells -...
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Transcript of Sexual Reproduction in Animals MaleFemale Gamete – sperm Gonad – testes Many sperm cells -...
Sexual Reproduction in Animals
Male Female
Gamete – sperm
Gonad – testes
Many sperm cells
- spermatogenesisSperm cells are(n) haploid/monoploid
Gamete – egg
Gonad – ovary
Few to many eggs
- oogenesisEgg cells are (n) haploid/monoploid
Sperm
*Smaller
*Swims through liquid
*Head, middle, & tail (flagellum)
Egg
*Larger than a body cell
*Cannot move on its own
*Round shape
Fertilization
• Sperm nucleus enters the egg and moves to the egg nucleus. The 2 nuclei join together and then form a zygote.
External Fertilization*outside the body
• Animals that breed in the water
• Many hazards in the environment– Sperm and egg may not meet– Eggs or offspring may be eaten– May die due to environmental conditions
• Temperature• Oxygen level
External Fertilization
• Large number of sperm and egg are released to overcome hazards
• Hormones control behavior to have sperm and egg released at the same time.
Internal Fertilization*within the female body
• Land animals
• Some aquatic animals– Shark– Octopus
Internal Fertilization
• Requires specialized sex organ to carry sperm to body of female
• Watery environment needed for sperm to swim to the egg
Internal Fertilization
• After fertilization, zygote is enclosed in a protective shell and released OR remains and develops in female body
Zygote Turtle laying eggs
• Internal Fertilization– Fewer eggs needed– Well protected – Increased chance of fertilization
Parthenogenesis – development of unfertilized egg into an adult.- Bees & Wasps
Mr. Lee’s Rap
• http://www.youtube.com/watch?v=_IOIx__UJ5g&feature=related
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