Transcript REPRODUCTION!!

Let’s Talk About …
REPRODUCTION!!
What do you know?
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There are two major types of reproduction.
Only bacteria and plants reproduce asexually.
Bacteria reproduce sexually and asexually.
There are animals that can reproduce asexually.
Homosexuality doesn’t exist in the animal world.
There is no benefit to asexual reproduction.
Plants engage in sexual reproduction.
Frogs and insects use external fertilization.
Some insects pass a large sperm package to
females during sex.
10.Hemaphrodites (have both sex organs) can
fertilize themselves.
Reproduction 101
Reproduction: Process by which new
individual organisms are produced.
There are two types of reproduction….
ASEXUAL
AND
Fungal Spores
SEXUAL
Asexual Reproduction
Asexual reproduction of algae
Asexual Reproduction: formation of new
individuals from a single parent. Offspring
are clones of the parent (unless mutations occur).
Who in the world would want to
reproduce asexually???
The following are examples of asexual
reproduction….
Bacteria
Bacteria reproduce through
binary fission.
Binary Fission—asexual
reproduction where one cell
divides into two genetically
identical cells.
Can bacteria have sex too?
• Conjugation: the transfer of genetic
material between bacteria through direct
cell-to-cell contact
– This is often mistaken as sexual reproduction,
but it’s NOT because it doesn’t involve the
fusion of gametes (sperm & egg).
Asexual reproduction of sea
anemone via binary fission!
Yeast and Sponges
• Yeast and sponges can
reproduce by budding.
• Budding--when a new
individual develops from
an outgrowth of a parent
YUCK!
• The outgrowth splits off
and lives independently!
Starfish
Fragmentation—when a single parent
breaks into parts that regenerate into a
whole new individual.
Strawberries
• Strawberry plants
send out runners to
start new plants.
• These new plants
are identical to the
parent plant.
Strawberries can also
reproduce sexually.
I’m so confused…..
Some species alternate between sexual and
asexual reproduction (heterogamy)
depending on conditions.
“I like to
reproduce
asexually
in the
spring
because
it’s fast and
easy.”
“I like to slow
things down in
the summer
and reproduce
sexually.”
Daphnia
VIRGIN SHARK
HAS BABIES!!
NEWSFLASH
There have been several cases in the last 10
years where captive sharks lay eggs that hatch
when NO MALES ARE IN THE TANK!!
Parthenogenesis --asexual form of reproduction
found in females where growth and development
of embryos occurs WITHOUT FERTILIZATION.
Parthenogenesis also occurs in some plants,
insects, reptiles, and birds (not in mammals).
Do parthenogenic females have
both sex parts?
• No! These animals are NOT
hemaphrodites (more on those later).
• Eggs develop without fertilization
• Offspring are clones of the female
“Lesbian Lizards”
• A female only species
• One animal takes the
"male" role and the
other the “female” role.
– Either can assume the
role depending on the
point in their cycle
• Mating ritual:
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Tongue-flicking of head
Neck stroking
Mounting
Genital touching
Is the lesbian sex just for fun?
• Instinct?
• Ancestral behavior?
• Improves fertility:
– When not allowed to engage in female-female sex
the laid eggs less often and laid fewer eggs.
Pro’s and Con’s of
Asexual Reproduction
• Quick, Easy, and
Guaranteed!
• No need to travel to find a
partner (less energy used)
• No arguments!
• Lack of variation
Sexual Reproduction
Sexual Reproduction: The formation of new
individuals following the union of two gametes
(sperm and egg).
Obviously, sexual reproduction involves TWO
parents instead of ONE.
You only think you know how this works!
Flowers have sex??
Simplified version of plant sex: pollen (plant sperm)
lands on the stigma (female part) and travels to the
egg (stored in ovary)
No Way! Say it isn’t so!
The fertilized egg develops into a seed and the
ovary develops into fruit.
Flowers
contain plant
reproduction
organs.
Hibiscus Sex Parts
Check out the sexy stigma (female pollen receptor)
and anther (produces pollen) on this plant ….
Pollination
“The Birds and the Bees”
Insects, wind, birds, bats, and “self” are all
methods of pollination—spreading sperm around!
What else can you tell me about
sexual reproduction???
Do fish
reproduce
sexually?
Fish Reproduction
External Fertilization: Female
fish expel eggs and the males
expel sperm (milt) into the water.
External Fertilization
Fertilized Salmon Eggs
Alevin (baby fish)
Frogs Do It Too
Sometimes they even try to do it
with the wrong species …
And sometimes doing it can
even be deadly …
Male Wood Frogs grasping a female
Some Do It Internally
Internal Reproduction: this is where the
penis is inserted into the female and sperm
is released to fertilize the eggs inside the
female’s body
Let’s take a look at who’s doing it
this way …
Insects Do It
Dragonfly Mating Wheel—female curls abdomen forward to receive sperm.
Examples of Insects Doing It …
Water striders
Spiny Soldier Bug
Monarch Butterflies
Praying Mantids
Ladybird mating
“I ain’t got nobody”
BOYS,
HOMECOMING
IS
SOON!
• Male insects attract females in a variety of
interesting ways:
– Chirping (crickets)
– Lighting up (fireflies)
– Dancing in swarms (mayflies)
– Odor or phermones (moths and butterflies)
TRY ONE OF
THOSE TRICKS!
What happens after insects mate?
Complete Metamorphosis
Reptile
Sexual Reproduction
“Are you my mother?”
There’s nothing very interesting about reptile life cycles. The
eggs hatch and the young grow…no fancy stages.
Bird Sex
They even do it in front of the kids! Eww!
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Bluebird Sex
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2
Birds have very interesting
courtship behaviors……
PLEASE CHECK ME OUT!!!
The male frigates inflate their
bright red jugular sac to attract
females.
Tufted Puffins rubbing bills
“Mammals … do it like
they do on the
discovery channel …”
I THINK YOU KNOW HOW THIS WORKS…
Pro’s and Con’s of Sexual
Reproduction
Increases Variation
One must attract a mate in
order to reproduce—this
can be energy consuming
and frustrating.
You’re telling
me!
One last question:
Do snails mate?
YUP …
We are hermaphrodites.
We are lucky enough to have both male
and female parts …
Then what were those
snails doing??
• Individuals contain both male and female sex
organs but they do NOT self-fertilize.
• The two to six hour marathon session that is
snail copulation is actually an exchange of
sperm between two individuals, combined with
plenty of rubbing, biting and 'eye-stalk' waving.
• Individuals use the received sperm to fertilize
their own eggs — a process that is necessary to
maintain genetic diversity in the population.
SWEET!
THE END!!