Ib 362 lecture 6
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IB 362 lecture 6. Reproduction, Dispersal and Migration in Marine Organisms. Reproduction. Behavior Regulation/effect of hormones Allocation of resources i.e. somatic vs. non-somatic tissue growth Method/frequency of fertilization Parental Care.

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IB 362 lecture 6

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Ib 362 lecture 6

IB 362 lecture 6

Reproduction, Dispersal and Migration in Marine Organisms


Reproduction

Reproduction

Behavior

Regulation/effect of hormones

Allocation of resources i.e. somatic vs. non-somatic tissue growth

Method/frequency of fertilization

Parental Care


Reproduction1

  • dominant/large males select best shelters

  • females select dominate male’s shelter and moves in

  • female will molt and then mate

  • after mating, female waits for shell to harden then moves out

  • other females in waiting move into shelter with olfactory cues

Reproduction

Behavior

North Atlantic Lobster – Homarus americanus


Reproduction2

Reproduction

  • no active searching for mates or pre-spawning behavior

  • females secrete pheromone after molting and any nearby male is attracted

Behavior

Opossum Shrimp


Reproduction3

Reproduction

Behavior

Regulation/effect of hormones

Allocation of resources i.e. somatic vs. non-somatic tissue growth

Method/frequency of fertilization

Parental Care


Lifetime reproduction two basic strategies

Lifetime Reproduction-two basic strategies

  • Iteroparous:

    • spawning possible more than once

    • most fishes and invertebrates

  • Semelparous:

    • spawning only once, followed by death

    • pacific salmon, some eels, lampreys


Lifetime reproduction two basic strategies1

Lifetime Reproduction-two basic strategies

  • Iteroparous:

    • spawning possible more than once

    • most fishes and invertebrates

  • Semelparous:

    • spawning only once, followed by death

    • pacific salmon, some eels, lampreys


Lifetime reproduction

Lifetime Reproduction

What are benefits and potential risks of each strategy?

  • Iteroparous

  • Semelparous


Advantages disadvantages

Advantages / Disadvantages

  • Iteroparous:

    +several opportunities

    + environment unpredictable

    - longevity expected

  • Semelparous:

    + maximum investment

    - unfavorable conditions


Mating systems

Mating Systems

number of mating partners an individual has during abreeding season

  • Promiscuous: little or no mate choice

  • Polygamous: one sex has multiple partners

    • Polyandry: one female, several males - rare

    • Polygyny: one male, several females - common

  • Monogamous: mates stay together, exclusively


Mating systems1

Mating Systems

  • Promiscuous

    • organisms that live in large groups

    • organisms with high fecundity

    • sedentary organisms


Mating systems2

Mating Systems

  • Polygamous – Polyandry / Polygyny

    • none to some parental care

    • nest guarding

    • relatively rare in marine organisms, especially beyond egg stage


Mating systems3

Mating Systems

  • Monogamous

    • defense of territory / resource

    • parental care by both parents

    • relatively rare in marine organisms


Extreme atypical mating systems

Extreme/Atypical Mating Systems

  • Monogamous

Males rely on females for nutrition - internal organs degenerate with

exception of testes


Gender roles

Gender Roles

  • Gonochoristic:gender fixed, determined early

  • Hermaphrodites:either both, or sex change

    • Simultaneous: eggs & sperm at same time

Hamlets


Gender roles1

Gender Roles

  • Gonochoristic:gender fixed, determined early

  • Hermaphrodites:either both, or sex change

    • Simultaneous: eggs & sperm at same time

    • Sequential : sex change during life


Sequential common in several marine fishes most common in wrasse family labridae

Sequential – common in several marine fishes (most common in wrasse family – Labridae)

Lyretail Coralfish:

  • Large aggregations

  • Sex-ratio 36F:1M

    • If x M removed, x F change sex


Sex change

Sex Change

Clownfish – 30 species

  • Two large and several small fish

  • largest = female

  • 2nd largest = male

  • rest = immature(even if same age as mature fish) but hiearchal by size

  • Body size maintained until change


Parental care

Parental Care

very diverse across fishes

Trade-off in resource allocation:

  • few, but high-quality

  • many, but low-quality

?

7

300,000,000


Fertilization

Fertilization

InternalExternal

Transfer of sperm in many invertebrates is via a spermatophore

  • Can be stored internally or attached externally

  • May provide nutrients to female

  • May prevent subsequent matings by other males

  • Decreased surface area


Fertilization1

Fertilization

Transfer of sperm in many invertebrates is via a spermatophore

  • Successful system, why not more common?


Fertilization2

Fertilization

Transfer of sperm in many invertebrates is via a spermatophore

  • Successful system, why not more common?

Metamerism – serial repetition of body regions

= more opportunity for appendage specialization


Fertilization3

Fertilization

  • Rare in invertebrates

  • Becomes more common in “higher” vertebrates

Internal (in body cavity)External


Ib 362 lecture 6

Open spawners

Brooders

External

pelagic

benthic

  • More common in marine fishes

  • Also known as broadcast spawners

  • Some benthic fishes will do it

  • high fecundity


Ib 362 lecture 6

Open spawners

Brooders

External

benthic

pelagic

  • gametes released into current

  • settle to substrate after fert.


Ib 362 lecture 6

Open spawners

Brooders

  • gametes can be stored internally

  • fertilization is external

  • fert. eggs carried (usually by females)

  • until hatching

  • more common in invertebrates

External


Ib 362 lecture 6

Open spawners

Brooders

External

  • parental care of juveniles after hatching

  • does occur but is rare, mostly in fishes

Cardinal Fish


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  • Occurs via splitting, budding or fragmentation

  • Generally rare, but more common in colonial organism at

  • the cellular level of organization

Asexual Reproduction


Dispersal

Dispersal

egg >> larvae >> juveniles >> adults

  • Most marine organisms have a larval stage


Dispersal1

Dispersal

egg >> larvae >> juveniles >> adults

  • Most marine organisms have a larval stage

  • Most freshwater organisms do not

  • Why the difference?


Dispersal2

Dispersal


Dispersal3

Dispersal


Dispersal4

Dispersal


Development larvae

Development - Larvae


Hatch egg to larvae

Hatch – egg to larvae

  • not tied to specific developmental stage

  • water temp and oxygen content

  • tide conditions, time of day, seasonal current changes

Hatching occurs at sunset of night of

strongest ebb tide

Coral Reef Flat Damselfish


Larval stage

Larval stage

Duration of larval stage dependant on resource needs in relation to currents

  • Food, habitat

  • 1 week to 18 months


Larval stage1

  • Two main types

  • Lecithotrophic –with yolk sac, no digestion

  • Planktotrophic – feed while larvae, digestion

Larval stage

  • Name different across taxonomic groups

Zoea – Crustaceans

Amphiblastula - sponges

Veliger – some molluscs

Leptocephalus – some fishes

Hard corals - planula


Larva unknown for many species

Larva – unknown for many species


Migration a directed movement

Migration – a directed movement


Migration a directed movement1

Migration – a directed movement


Migration a directed movement2

Migration – a directed movement


Migration a directed movement3

Migration – a directed movement


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