Lec 13 Reproduction

Question 1

Eugene K. Balon

Answer 1

envisioned of ecological and ethological classification of reproductive systems.

Question 2

The majority of fishes uses what kind of reproduction?

Answer 2

They’re oviparous, so the eggs are reproduced, laid and then fertilized.

Question 3

Eggs come in two kinds

Answer 3

1. Pelagic eggs that float
2. demersal eggs that sink

Most marine fishes start out life as pelagic eggs

Question 4

The marjority of marine fishes that start off as pelagic eggs includes

Answer 4

1. most fishes that live over continental slope
2. nearly all those that range over surface waters of the open ocean
3. pelagic deep sea fishes.

Question 5

How are pelagic eggs able to float?

Answer 5

made buoyant by low density fluids from folicle cells or they develop an oil droplet independent of ovacrian tissue.

Question 6

What is the epipelagic zone?

Answer 6

upper sun lit layers of the ocean.

Question 7

definition of nursery grounds

Answer 7

rish, upper, sun lit layers that are able to support the myraid of developing forms

Question 8

What happens when the eggs hatch?

Answer 8

colorless larvae live off stored yolk, when its used up, they begin to feed on tiny phytoplankton and zooplankton

Question 9

Fishes that produces floating eggs must also do what?

Answer 9

produce a large number of small eggs.

an example
mola mola 300 million

Question 10

Why would high numbers of pelagic eggs be important?

Answer 10

Neccessary for successful recruitment cuz thousands of eggs and larvae and disperse to area beyond optimal conditions.

Has wide geographic distributions

Question 11

Where are demersal eggs usually placed?

Answer 11

In nests, fastened to rocks, shells seaweed, sponges.

Question 12

Where do the fishes that lay demersal live near?

Answer 12

They live in near shore waters.

Ex fishes blennies, gobies and other tidepool forms.

Question 13

What’s the advantages of demersal eggs?

Answer 13

It sinks, so it’s more suited for tidepool environments. While floating eggs would be smashed up.

Question 14

What kind of geographic distribution do demersal eggs have?

Answer 14

Restricted geographic distribution.

The eggs sink and are unlikely to be swept into unfavorable regions.

Question 15

What are the size of demersal eggs?

Answer 15

Larger eggs, larger concentration of yolk. Later development. Fewer eggs

Question 16

Are demersal or pelagic eggs more vulnerable to predation?

Answer 16

The demersal eggs since it is less likely to be swept away from tides. Usually they can be hidden by burying them in sand or under a rock. Some have parental care to guard the eggs.

Question 17

Which egg is the rule for freshwater?

Answer 17

Demersal.

1. Physiologically more difficult to produce an egg with a sp gravity < freshwater
2. freshwater doesn’t provide rich food resource in upper layers compare to marine env
3. fast movin rivers and streams would remove nearly all eggs and larvae from local population

Question 18

Nearly all freshwater fishes deposit eggs that are sticky or scattered?

Answer 18

sticky and sink to bottom.

Others have many non adhesive eggs that scatter

Question 19

What are some derived strategies to protecting eggs?

Answer 19

1. bury or lay eggs in some kind of nest

2. hide and protect eggs in other organisms, i.e european bitterling deposits eggs inside freshwater mussels

Question 20

What’s the difference between ovoviviparous and viviparous? How are they similar?

Answer 20

Similar: both are live bearing and require internal fertilization
Difference, ovovivivparous are eggs that are in the mom. Viviparous is when young is nourished by some placental connection with mother.

Question 21

Example of ovovivipartiy and viviparity

Answer 21

It’s pretty rare among fishes.

i.e Chondrichthyes, live bearers, freshwater half beak, scorpioni fishes, surfperches, eel pouts

Question 22

What is an intromittant organ?

Answer 22

Involved in internal fertilization.

Structure used to pass sperm to the female.

Question 23

What is the best known case of ovoviviparity?

Answer 23

Eggs are fertilized within egg follicles of ovary and develop for sometime.

Question 24

What is a simple kind of pseudoplacenta?

Answer 24

Wall of ovarian follicle acquire network of capillaries that extend out as villi and make intimate association with external surface of developing embryos.

Question 25

What is the branchial placenta?

Answer 25

A more efficient pseudoplacental. Linging of ovary forms highly cascularized folds that makes contact with gills of developing ovaries.

Question 26

What is the process of trophonema/trophotaenia.

Answer 26

food absorbing processes that grow out of the hind gut of the embryo

Question 27

What is parental care?

Answer 27

when eggs are retained after being laid.

Question 28

Forms of parental care, four kinds

Answer 28

1. male parental care: sea catfishes, sticklebacks
2. Female parental care: 3 types
3. biparental care: bullheads
4. juvenile helpers

Question 29

3 types of female parental care

Answer 29

1. oviparity with post spawning care
2. ovoviviparity w/o post spawning care
3. viviparity w/o post spawning care

Question 30

explaing a type of male parental care

Answer 30

oral incubation.

the male keeps the eggs well oxygenated and protected from predation.

Question 31

how do bunocephalid catfishes care for the young?

Answer 31

They lie down on the eggs after it’s been laid and fertilized. The eggs sink to underside and sticks there.

Question 32

How does nurseryfishes care for the eggs?

Answer 32

Has bony hook on forehead, the hook is used to carry eggs which are in two bundles connected by a fibrous thread.

Question 33

What kind of fishes tend to be hermaphrodites?

Answer 33

Deep sea fishes. There’s a definite trend toward an increase in the number of hermaphroditic species with depth.

Question 34

Why do hermaphrodites occur at the depth they do?

Answer 34

increase scarcity of food with increasing depth causes reduction in population. So meeting between sexes are fewer.

Question 35

What’s the difference between sex reversal and hermaphrodites?

Answer 35

Hermaphrodites has both reproductive organs. THe other has the ability to completely change its sex over.

Question 36

When does sex reversal occur?

Answer 36

When no males are present. The females become male and act like one too.

Question 37

What is protandry?

Answer 37

First half of the life cycle is spent in male state.

Question 38

What is protogyny?

Answer 38

When they’re first females.