Lecture 7: Reproduction

• What is notable about the hagfish reproductive system?

  Single gonad present in both sexes

  Gonad not differentiated at birth

  Anterior part of the gonad is ovarian tissue

  Posterior part of the gonad is testicular tissue

  Iteroparous
• What part of a hagfish gonad is ovarian tissue?

  Anterior
• What part of a hagfish gonad is testicular tissue?

  Posterior
• What term goes in the pink box of this diagram of a hagfish egg?

  Anchor Filaments

  
• What term goes in the lavender box of this diagram of a hagfish egg?

  Opercular Ring

  
• What term goes in the blue box of this diagram of a hagfish egg?

  Microphyle

  
• What is notable about the reproductive system of lamprey?

  Single gonad present in both sexes

  Ammocoete stage shows sexual intermediacy

  It's possible there is no genetic sex determination

  Environment, resources, & early life experience determine sex

  Semelparous
• How much of a lamprey's body is designated to reproductive organs?

  1/3
• What is notable about female lamprey in the reproductive process?

  Females may mate without releasing eggs

  Females suppress egg release when there are more males

  The size of the male impacts egg release

  Bigger, more vigorous males spur more eggs to be released

  Females show mate choice
• Why is iteroparity a suitable reproductive strategy for hagfish?

  Hagfish live in an open ocean environment

  Hagfish have no assured next meal

  Hagfish offspring have a high chance of death

  Reproducing once is highly likely to lead to waisted effort
• Why is semelparity a suitable reproductive strategy for lamprey?

  They expend a lot of energy on spawning runs

  Offspring are unlikely to have varying resources

  Offspring have a high survival rate
• What is the red arrow pointing to in this diagram of a male shark gonad system?

  Testies

  
• What is the orange arrow pointing to in this diagram of a male shark gonad system?

  Misorchium

  
• What is the yellow arrow pointing to in this diagram of a male shark gonad system?

  Kidney

  
• What is the green arrow pointing to in this diagram of a male shark gonad system?

  Vas deferens

  
• Describe the evolutionary trend?

  Least advanced -> most advanced

  Most advanced has separation of the vas deferens from the kidney

  
• What is the purpose of the sperm sac?

  To store sperm ready to be released
• What is the purpose of the siphon?

  To pump in seawater so the sperm can be ejected
• What is the purpose of the Epididymides?

  To release sperm from the testies into the Vas deferens
• What is the purpose of Leydig's gland?

  Secrete supplementary material the sperm need upon release
• What is #4 in this diagram of a male Chondrichthyes reproductive tract?

  Clasper

  
• What is #8 in this diagram of a male Chondrichthyes reproductive tract?

  Ductus Deferens / Vas Deferens

  
• What is #9 in this diagram of a male Chondrichthyes reproductive tract?

  Epididymis

  
• What is #12 in this diagram of a male Chondrichthyes reproductive tract?

  Left testis

  
• What is #13 in this diagram of a male Chondrichthyes reproductive tract?

  Leydig's gland

  
• What is #22 in this diagram of a male Chondrichthyes reproductive tract?

  Seminal vesicle

  
• What is #23 in this diagram of a male Chondrichthyes reproductive tract?

  Siphon

  
• What is #24 in this diagram of a male Chondrichthyes reproductive tract?

  Sperm sac

  
• Rhipidon: Part of the male Chondrichthyes reproductive system that locks the female in place to ensure successful mating
• What is notable about the reproductive system of Chondrichthyes?

  Paired gonads present in both sexes

  Internal fertilization

  Large offspring

  Variety of reproductive methods

  Females can store sperm for at least one year

  Immature females can store sperm
• What goes in the red box of this diagram of a female shark reproductive tract?

  Ovaduct

  
• What goes in the orange box of this diagram of a female shark reproductive tract?

  Club

  
• What goes in the yellow box of this diagram of a female shark reproductive tract?

  Papillary

  
• What goes in the lime box of this diagram of a female shark reproductive tract?

  Baffle

  
• What goes in the green box of this diagram of a female shark reproductive tract?

  Terminal

  
• What is the Fisherian Chase Away?

  When the males of a species have different fitness needs then the females of a species. This results in a cycle of males becoming more coercive and the females becoming more resistant resulting in intra-sexual conflict which can then create altered benefits for the participants
• What is an example of a female resistance strategy of the Fisherian Chase Away?

  Female hammerheads forming schools where the biggest and oldest remain in the center to avoid mating
• What is the noted reproduction strategy of the Actinopterygii?

  Paired gonads present in both sexes

  Variety of strategies

  Reorganization of the urogenital system to further attach the testies / ovaries to the kidney
• What is notable about the mesonephros in the reproductive system of fish?

  In more ancient fish the testies and ovaries are connected to the kidney via mesorchium / mesovarium.

  In more ancient fish the vas deferens is connected to the kidney

  In more evolved fish the reproductive system and urogenital system disconnect

  In more advanced female fish there is a secondary loss of the oviduct
• What is the evolutionary trend in the connection of the ovary to the kidney in fish?

  Most ancient -> most advanced