Which treatment group resulted in the largest number of snails matings?
Matings of A. arbustorum last 8-18 h and include elaborate courtship behavior with optional dart shooting (Baur 1992;Baminger et al. 2000). It has been shown that …
What conclusion (s) about snail mating can be drawn from the graphs?
Higher mating rates, independent of the number of individual mates, resulted in lower fecundity but higher investment per egg in the pond snail Lymnaea stagnalis (LINNAEUS 1758) (Hoffer et …
How do freshwater snails mate?
May 13, 2020 · The snail will use its “muscular foot” to shovel dirt and build a nest for anywhere between 30 and 120 eggs. The average number of eggs in a garden snail nest is 86. Eggs are only 1/8 of an inch in diameter and are covered by a concoction of mucus, soil, and excrement created by the parent snail.
How many eggs do snails lay at once?
Jan 11, 2022 · 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. The eggs typically hatch after …
What conclusion's about snail mating can be drawn from the graphs?
What conclusion(s) about snail mating can be drawn from the graphs? Having only worms present results in more snail mating than when only bacteria are present. Having only bacteria present results in less snail mating than when there are no bacteria and no worms.
What does meiosis II produce?
Meiosis II produces 4 haploid daughter cells, whereas meiosis I produces 2 diploid daughter cells. Genetic recombination (crossing over) only occurs in meiosis I.Jan 27, 2018
Which of the following occurs during meiosis I?
In meiosis I, chromosomes in a diploid cell resegregate, producing four haploid daughter cells. It is this step in meiosis that generates genetic diversity. DNA replication precedes the start of meiosis I. During prophase I, homologous chromosomes pair and form synapses, a step unique to meiosis.
Which of the following occurs during meiotic anaphase?
The correct answer: The condition which occurs specifically during Anaphase I is c. Homologous chromosomes separate.
How is prophase I different from prophase II in meiosis?
The main difference between prophase 1 and 2 is that genetic recombination occurs through crossing overs and the “Chiasmata” formation during prophase 1 whereas no genetic recombination is noticed at the prophase 2.Mar 14, 2017
How many divisions occur in meiosis?
Two divisionsTwo divisions, meiosis I and meiosis II, are required to produce gametes (Figure 3). Meiosis I is a unique cell division that occurs only in germ cells; meiosis II is similar to a mitotic division.
What is the end result of meiosis?
The result of meiosis is 4 gametes, or sex cells, that each contain half of the genetic information in the parent organism.Dec 9, 2021
How many divisions occur during meiosis quizlet?
How many cell (or Nuclear) divisions occur in mEiosis? In meiosis, there are two cell divisions, making 4 daughter cells, all different from the mother and from one another.
Does mitosis occur in animal cells?
Mitosis is the process in cell division by which the nucleus of the cell divides (in a multiple phase), giving rise to two identical daughter cells. Mitosis happens in all eukaryotic cells (plants, animals, and fungi). It is the process of cell renewal and growth in a plant, animal or fungus.Mar 1, 2022
Why does prophase take the longest?
Why is prophase the longest? The longest phase of mitosis is prophase because During prophase, which occurs after G2 interphase, the cell prepares to divide by tightly condensing its chromosomes and initiates mitotic spindle formation. The chromatin fibers condenses into discrete chromosomes.Dec 14, 2021
Which of the following occurs during prophase?
During prophase, the nuclear envelope dissolves and chromosomes condense. The chromosomes migrate to the center of the cell and align during metaphase. The mitotic spindle fibers attach during metaphase and retract during anaphase, pulling sister chromatids from each chromosome to separate poles of the cell.
What process occurs during prophase 1 of meiosis?
During prophase I, the complex of DNA and protein known as chromatin condenses to form chromosomes. The pairs of replicated chromosomes are known as sister chromatids, and they remain joined at a central point called the centromere.
How long does it take for a snail to court a squid?
They will often follow a mucus trail left behind by a prospective mate and once they find this fellow snail, the courtship process can occur from anywhere between 2 and 12 hours. The process begins with the two snails touching, usually with their tentacles, and sometimes a biting of the other’s genital pore.
How many eggs do snails lay?
The snail will use its “muscular foot” to shovel dirt and build a nest for anywhere between 30 and 120 eggs. The average number of eggs in a garden snail nest is 86. Eggs are only 1/8 of an inch in diameter and are covered by a concoction of mucus, soil, and excrement created by the parent snail.
How long does it take for a snail to grow eggs?
Often both snails will receive sperm and thus grow eggs within, burying them separately approximately three to six days after being fertilized.
What are love darts?
They can leave relatively large punctures in the snail, but these animals are adapted to the process. The “love darts” are not used for the transfer of sperm but were found to be a form of sexual selection.
Is a snail a hermaphrodite?
0. Shares. Most snails, including the commonly known garden snail, are hermaphrodites. This means they contain both male and female reproductive organs and produce eggs and sperm. The pomatidae family is the exception, in which males and females are separate, denoted by a smaller and larger shell, respectively.
Do snails mate with other snails?
Although in species that host both parts the snails are capable of self fertilization, or asexual reproduction, they will still often mate with another snail. At the base of the body and below the head, the reproductive system ends in an opening called the genital pore.
How many species of snails are there in the world?
Snails are a common aquarium addition because they eat algae and keep the tank clean. What you may not have realized is that there are around 5,000 different species of freshwater snails! They can all be found classified under the scientific class Gastropoda. As you might imagine, with such a huge number of species, they can be found in many places around the world in freshwater lakes, streams, ponds, rivers and, of course, aquariums.
Do snails lay eggs in water?
Some species do lay their eggs out of the water, and the juvenile snails go back into the water after they hatch.
What is the amino acid sequence of cytochrome C?
The amino acid sequences of cytochrome c (an enzyme in mitochondria) differ between humans and chimps by one amino acid. B. If the gene for human insulin is inserted into bacteria, the bacteria can make human insulin.
Where do horse fossils come from?
E. Horse fossils occur in North America even though there were no wild horses in North America in 1492. Don't know. Imagine that a phylogeny was developed for a group of mammals based on bone structure.
What happens when you stop taking antibiotics?
Then, when people stop taking the antibiotics, the strong bacteria that survived have been selected, breed with one another, and create a stronger population. C.
Why don't fish have eyes?
A.The fish were in a dark environment and therefore didn't need eyes. Over time, they used their developmental energy for other more useful features, so because they didn't use them, they lost them. B. The fish never had eyes but are slowly evolving to have them because they might need them in the future.
Where is Cynotilapia afra located?
Cynotilapia afra, introduced at West Thumbi Island in Lake Malawi in the 1960s, has split into two genetically distinct populations, located at the north and south ends of the island. How can scientists determine whether these populations are now different species, according to the biological species concept? A.
Do fish have eyes?
The fish never had eyes but are slowly evolving to have them because they will need them someday. B. Originally, some fish in the population had eyes and could see, but those without eyes had more acute other senses, allowing them to eat, avoid being eaten, and find a mate more easily.
Is a short horned cow heterozygous?
Red short-horned cattle are homozygous for the red allele, white cattle are homozygous for the white allele, and roan cattle are heterozygotes. Population A consists of 36% red, 16% white, and 48% roan cattle.
Introduction
While the sex with the lowest investment per offspring (usually the male) increases its reproductive success with increasing number of mates, the sex investing most in each offspring (usually the female), might be expected to experience diminishing fitness returns with increasing number of matings (Bateman 1948; Trivers 1972 ).
Materials and methods
In littorinids, males actively locate females by following their mucus trails (Ng et al. 2013 ). Upon encountering a female, the male initiates mating by mounting the female, explores the shell by counter-clockwise movements over the shell into the copulation position, and finally inserts the penis under the female’s shell (Saur 1990 ).
Results
In total, 549 offspring were genotyped out of 668 born juveniles from the two-male, five-male and ten-male families, and of these, 522 (95 %) were successfully assigned to a father and included in the downstream analyses (Table 1 ).
Discussion
We here show some important life history traits of this species. First of all, we show that females of L. saxatilis are able to store functional sperm for more than a year. Secondly, we show that females mate with a majority of available males, as juvenile offspring sired by all or the majority of available males were present in all families.
Acknowledgments
We thank Emma Johansson, Mikael Dahl, Chris Weller and Bo Johannesson for technical support, and Terence Ng, Emilio Rolán-Alvarez and two anonymous reviewers for useful comments on earlier versions of the manuscript.
Author information
Kerstin Johannesson, Sara Hintz Saltin, Gregory Charrier, Anna-Karin Ring, Carl André & Marina Panova
Abstract
Despite growing evidence that population dynamic processes can have substantial effects on mating system evolution, little is known about their effect on mating rates in simultaneous hermaphrodites.
Background
There is increasing awareness that ecological processes such as changes in population demography can substantially affect the evolution of mating systems (reviewed in [ 1 ]).
Results
Mate encounter rates strongly increased with both mating group size and population density (Table 1; Figure 1a ), with an approximately 2-fold increase each from the lowest to the highest density categories and from the smallest to the largest mating groups.
Discussion
We found that mate encounter rates and thus mating opportunities increased with both group size and density. Despite this, the average individual mating rate remained largely constant and close to the earlier detected fitness optimum of the female function in C. sandrana [ 23 ].
Conclusions
Contrary to classic predictions by theory, we here show for the first time that mating rate is largely unresponsive to variation in mate availability in a simultaneous hermaphrodite.
Methods
Chelidonura sandrana Rudman 1973 (Cephalaspidea, Aglajidae) inhabits tropical marine shallow water sand flats. Copulations are unilateral, but sexual roles are usually alternated during a copulatory bout, resulting in reciprocal sperm exchange (details in [ 28 ]).
Acknowledgements
We are grateful to Hanna Kokko, Roger Härdling, and two anonymous referees for valuable comments on a previous draft of this manuscript, Kate Kunigelis for support during field work, and the staff at Lizard Island Research Station, Queensland, Australia, for excellent logistic support. This work was funded by a DFG grant to Nico K.