What is a reproductive strategy?
What is a reproductive strategy?
The term reproductive strategy is loosely used to refer to the way an animal mates and/or raises offspring. It could refer to things like sexual vs. asexual reproduction. It could also refer to one reproductive episode in a lifetime, semelparous reproduction, vs.
Why are gastropods hermaphrodites?
Gastropods are capable of being either male or female, or hermaphrodites, and this makes their reproduction system unique amongst many other invertebrates. Hermaphroditic gastropods possess both the egg and sperm gametes which gives them the opportunity to self-fertilize.
What type of habitat do gastropods live in?
Gastropods live both in terrestrial (land) and marine environments, although the vast majority live in the waters of the world. Gastropods have a variety of different diets. Some species, like abalones, scrape algae from rocks along the ocean floor.
What are two examples of reproductive strategies?
Examples include breasts, showy tails and headpieces, and crazier traits like the length of the eye-stalks in stalk-eyed flies. Sexual dimorphism can lead to specific behaviors in males that increase their reproductive success.
What are the three types of reproductive strategies?
Vertebrates have one of the following three reproductive strategies: ovipary, ovovivipary, or vivipary.
- Ovipary refers to the development of an embryo within an egg outside the mother’s body.
- Ovovivipary refers to the development of an embryo inside an egg within the mother’s body until it hatches.
How do gastropods reproduce asexually?
Snails reproduce the same way almost everything else does – they mate and lay eggs. Some snails are hermaphrodites, though (have both male and female sexual organs in the same individual), which means that two snails can fertilize each-other.
How do snails reproduce?
What time period did gastropods live in?
Gastropods are a class of mollusk animals that includes snails and slugs. Gastropods came into existence during the earliest part of the Paleozoic Era about 520 million years ago and persist to present day in a variety of forms and lifestyles.
What are three reproductive strategies?
Vertebrates have one of the following three reproductive strategies: ovipary, ovovivipary, or vivipary.
Which is a reproductive strategy used by males?
The Ideal Male Reproductive Strategy The optimal reproductive strategy of a hypothetical male primate is characterized by rapid sexual maturation, followed by life-long exclusive access to an unlimited number of fertile females willing to mate, and offspring survival should be independent of paternal care.
What is R and K reproductive strategy?
The symbols r and K originate in the mathematics of population biology and refer to 2 ends of a continuum in which a compensatory exchange occurs between gamete production (the r-strategy) and longevity (the K-strategy).
How do snails impregnate themselves?
They have both female and male reproductive cells (they are hermaphrodite). They don’t actually need to mate with another snail in order to reproduce, self fertilisation is possible. After mating they lay around 80 white eggs in a damp, underground nest.
Do land snails reproduce asexually?
Snails of different species have different anatomies, behaviors and habitats. Some snails are hermaphrodites, some reproduce sexually and some freshwater pond species reproduce asexually. A few species, including the New Zealand mud snail (Potamopyrgus antipodarum), can reproduce both sexually and asexually.
How often do snails reproduce?
Snails can lay eggs multiple times a year, sometimes as often as once or more each month. Depending on the species, there can be anywhere from 5 to 200 or even 600 eggs in a single bunch. For example, the Chinese mystery snail can lay up to about 100 eggs at a time, but Ramshorn snails will usually only lay 10 to 12.
Are gastropods asexual reproduction?
Some species regularly self-fertilise. Uniparental reproduction may also occur by apomixis, an asexual process. For the most part, however, land slugs do mate: they find partners, and engage in elaborate courtship rituals before actual sperm transfer takes place.
When did gastropods go extinct?
Many gastropod taxa went extinct during the Late Cretaceous. The stratigraphic ranges of 268 genera permit to establish the longevity of extinction victims for each stage of this epoch. “Young” taxa (originated within 3 epochs before the extinction) prevailed among victims of the extinctions in all stages.
What is R and K selection and how do they differ?
A whale tends for a single calf. r-selection: On one extreme are the species that are highly r-selected. r is for reproduction. Such a species puts only a small investment of resources into each offspring, but produces many such low effort babies….r- and K-selection.
| Characteristic | r | K |
|---|---|---|
| Lifespan | short | long |
| Early mortality | high | low |
How do land snails reproduce?
Land snail eggs usually result from sexual reproduction, in which genetic material from two individuals is combined. The genetic material in eggs and sperm are brought together by internal fertilization, which involves copulation, though it is much different from that in mammals.
What is Pulmonata?
Jump to navigation Jump to search. Pulmonata, or “pulmonates”, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includes many land and freshwater families, and several marine families.
What are the ancestors of Pulmonata?
The subclass Pulmonata evolved from opisthobranch (marine gastropod mollusks of the subclass Opisthobranchia) ancestors, although it is uncertain to which opisthobranch group they are most closely related. The pulmonates include a number of marine and freshwater families within several orders, but are predominantly terrestrial.
What are the four orders of Pulmonata?
The four orders of Pulmonata, based on Burch 1982 and Jeffrey 2001, are the Stylommatophora (terrestrial snails and slugs), Basommatophora (mostly freshwater, also some terrestrial and marine snails and slugs); Systellommatophora (sluglike); and Actophila (marine, intertidal, and brackish-water snails).
Where do pulmonates live?
They typically live on or near the ground surface, although some families of slugs spend most of their lives burrowing in the soil, and many snails (and a few slugs) are arboreal. Pulmonates outside the Stylommatophora inhabit tropical and temperate regions. Basommatophorans are mostly freshwater, living in ponds, lakes, streams, and rivers.