Diplontic Life Cycles

Flashcards about Diplontic Life Cycles in Animals

Diplontic Life Cycle

Life cycle where diploid adults produce haploid gametes by meiosis; fertilization of haploid gametes produces a diploid zygote, which grows by mitosis into a new diploid individual.

Direct Development

Continuous growth until adult form is reached.

Indirect Development

Juveniles exist as larvae and then undergo a metamorphosis into their adult form.

Asexual Reproduction

Lacks gametes and fertilization; occurs by external budding, fragmentation.

Amoebocytes

Totipotent sponge cells that can change into other types of cells that make spicules/spongin; they move throughout the mesohyl.

Broadcast Spawning

When sperm are produced by choanocytes and are released through the osculum into the water.

Parenchymula Larva

A ball of cells with flagella on the outside

Polyps

Reproduce asexually and produce genetic clones by budding, fission, or pedal laceration.

Planula Larva

Swimming, ciliated larva that develops from a zygote.

Polymorphic Polyps

Individual polyps or “zooids” are produced asexually and have different functions in the colony such as feeding or reproduction.

Gastrozooids

Feeding polyps with tentacles.

Gonozooids

Reproductive polyps that asexually produce small medusae that bud off and swim away.

Ephyra

Temporary polyp asexually buds off new juvenile medusae .

Echinoderm Regeneration

Ability to regenerate lost parts of their bodies from stem cells; usually, the lost part must contain part of the central disk in order to regenerate.

Trematoda and Cestoda

Flatworm parasites that dedicate the majority of their body to reproduction.

Gravid Proglottids

Posterior segments of tapeworms filled with fertilized eggs, which detach and leave host via feces.

Cercaria Larva

Swimming larvae of blood flukes ingested by snails.

Monecious

Animals having both male and female reproductive organs in the same individual; earthworms, barnacles, marine flatworms

Definitive Host

Host in which sexual reproduction occurs

Intermediate Host

Host in which asexual reproduction occurs

Earthworms

Annelids which exchange sperm

Barnacles

Adults are sessile and attach “head down” (acorn barnacles) or by a stalk (gooseneck barnacles); are hermaphrodites with the largest penis‐to‐body-size ratio in the animal kingdom!

Marine Flatworms

Most flatworms are monoecious with internal fertilization after individuals exchange sperm.

Cephalopods

Male transfers a spermatophore (sperm packet) to female using a modified arm (hectocotylus);

Arachnids

Male spiders spin a spermatophore package that he deposits into the female genital opening.

Spermatophores

Salamander and newt (Amphibian) males also create these to transfer sperm. Females can choose to collect for internal fertilization.