non-mammalian reproductive strategies

8/13/2019 Non-Mammalian Reproductive Strategies

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NON

-

MAMMALIAN

REPR

ODUCTIVE

STRATEGIES


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SEXUAL

REPRODUCTION

ASEXUAL

REPRODUCTIVERSUS


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S

REPRODUCThe creation of

the fusion of hapl

to fo

The dipl

the un

gametes


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S

REPRODUCGametes are form

meiosis. There ar

ovum andsp

The femala haploid, un

usually large a

The

generally sm


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ADVANTAG

SEXUAL REPRODUCIt creates ge

One scientist,Alexey

suggests that sexual rpurges the species o


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DISADVANTAG

SEXUAL REPRODUCEnerg

Genetic reco

counter-pcondition


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DISADVANTAG

SEXUAL REPRODUCOnly half of the

made can produ

(males are the e

Less

passi

Risk of losing

combinat


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ASEXUAL

REPRODUCTIONGeneration of new individuals

without the fusion of egg and

sperm

Relies entirely on mitotic cell

division

Some species are purely

female


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ADVANTAGES OF

ASEXUAL REPRODUCTIONHigher frequency of production

every generation

Good in maintaining successfulgenotypes in favorable

conditions and environments


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DISADVANTAGES OF

ASEXUAL REPRODUCTIONSlower adaptation rate

Slower mutation rate

More susceptible to widespread

death due to disease


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MECHANISMSOF ASEXUAL REPRODUCTION


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FCertain animals like sea athe ability to separate the

organisms of approximate

size


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BuAnimals like pill

the left reprodu

outgrowths of e

wherein they rem

and form a colonone meter long.


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SpecializeSome invertebrates, inclu

sponges, release speciali

cells that can grow into ne


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Fragmentation and RegeAnimals like earthworms and planaria

ability to reproduce from parts of the

were previously separated from the body


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ParthenoThe ability of

and a few ve

which an eg

even without

In invertebraobserved in

and ants. In

this is really

observed in

dragon and in

hammerhead


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CHOICE OF

REPRODUCTIVESTRATEGY

HORMONALAND


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HORMONAL AND

ENVIRONMENTAL CUESSome animals show definite

cycles in reproductive activity

Ewes ovulate at the midpoint of

their 15-day cycle which occurduring fall and early winter

This shows that reproduction is

controlled by both hormonal and

environmental cues

SWITCHING


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SWITCHINGDaphnia, switch from sexual to

asexual reproduction

Asexual reproduction

occurs at favorableconditions

Sexual reproduction

occurs at times of

environmental stress

Parthenogenesis is the reason

for this

HERMAPHRODITISM


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HERMAPHRODITISM

Sessile or burrowing animals are usually hermaphroditic

since the chances of encountering a fellow organism of a

different sexif they were not hermaphroditicis low

SEQUENTIAL


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SEQUENTIAL

HERMAPHRODITISMAnother type of hermaphroditism issequential

hermaphroditism

The sex reverses during its lifetime

Protogynous (female first) orprotandrous (male first)

non-mammalian reproductive strategies

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