How did some stickleback populations come to live exclusively in fresh water How did some stickleback populations come to live exclusively in fresh water?
How did some stickleback populations come to live exclusively in fresh water? Some stickleback populations became trapped in lakes that formed at the end of the last ice age. In lakes with dragonfly larvae, pelvic spines can be disadvantageous, allowing the predatory larvae to grab the fish.
Which of the following helps to explain why some freshwater stickleback fish populations lack pelvic spines?
2. Which of the following helps to explain why some freshwater stickleback populations lack pelvic spines? Pelvic spines are homologous to legs in four-legged animals, and freshwater stickleback fish don’t need hind limbs to move.
What is the difference between marine sea-run and freshwater stickleback fish populations?
Marine stickleback populations live and breed strictly in the ocean. Sea-run stickleback fish are anadromous, meaning that they are born in fresh water, spend most of their lives in the ocean, and return to fresh water to breed. Freshwater stickleback fish live entirely in fresh water.
How do multiple lines of evidence work together to illustrate stickleback evolution?
How do multiple lines of evidence (from the field, the fossil record, and molecular genetics) work together to illustrate stickleback evolution? Genetic evidence reveals the precise molecular mechanism responsible for the change in pelvic structures in stickleback populations.
Why did the stickleback fish lose its spines?
One adaptation was the loss of pelvic spines, which are homologous to the hind limbs of four-legged animals. Scientists have determined that changes to the stickleback pelvis are largely due to changes in a particular gene regulatory switch, a stretch of noncoding DNA sequence that functions to turn genes on or off.
Why did Kingsley and his team cross marine and freshwater?
Why did Kingsley and his team cross marine and freshwater sticklebacks? To find the location of the gene(s) causing the difference between stickleback populations with and without spines. It occurred in a similar DNA region in freshwater stickleback populations all over the world.
What can be inferred about the presence or absence of predatory fish when the Truckee formation was a lake?
Because pelvic spines in living three-spined stickleback populations provide a defenseagainst large predatory fish, we can infer that there probably were no predatory fish in the ancient lake.
How did ancestral populations of ocean-dwelling fish?
How did ancestral populations of ocean-dwelling fish come to live in freshwater lakes? became trapped in these lakes and adapted to living exclusively in fresh water. populations have reduced armor.) Explain how the stickleback armor protects the fish from some predators.
What happened to these fish as they adapted to living exclusively in fresh water?
What happened to these fish as they adapted to living exclusively in fresh water? As they adapted to life in fresh water, all stickleback populations living in lakes in Alaska underwent exactly the same evolutionary changes.
How were the saltwater stickleback fish able to adapt to a freshwater environment so quickly quizlet?
age, new freshwater lakes, and stickleback swam to these lakes from the ocean. As more and more ice melted, connections between some of the lakes and the ocean were cut off, and stickleback populations became trapped in these lakes. Because of this, they adapted to living exclusively in fresh water.
How did some ancestral Sea stickleback populations come to live exclusively in freshwater a they became trapped in lakes that formed at the end of the last ice age b they don’t actually live exclusively in fresh water they only live in freshwater?
1. How did some ancestral sea-run stickleback populations come to live exclusively in fresh water? These populations swam to freshwater lakes to spawn and then never returned to the ocean because there were fewer predators in lakes. They became trapped in lakes that formed at the end of the last ice age.
What can we infer from rejecting the null hypothesis in this particular experiment?
What does it mean when a null hypothesis is rejected? There is no statistically significant difference between the observed and expected data. There is no statistically significant difference between the observed and expected data. Therefore, the difference is due exclusively to chance.
What type of stain did we use for the fish?
The technique Summers uses to clear and stain fish has been common practice of reasearchers for decades and relies on two dies: Alcian blue, which gives cartilage a blue hue, and Alizarin Red S, a red dye that acts on bone.
What does it mean when a null hypothesis is rejected stickleback?
what does it mean when the null hypothesis is rejected? there is a difference between the observed and expected data and it is unlikely that the difference happened by chance.
What does P value measure?
The P value is defined as the probability under the assumption of no effect or no difference (null hypothesis), of obtaining a result equal to or more extreme than what was actually observed. The P stands for probability and measures how likely it is that any observed difference between groups is due to chance.
What is an important difference between Bear Paw Lake and Frog Lake?
(1 point) Fish in marine and sea-run populations have complete pelvises; the pelvic spines protect stickleback fish from larger fish that prey on them in the ocean. Most stickleback fish in Bear Paw Lake have either a reduced or an absent pelvis, whereas those in Frog Lake have a complete pelvis.
Why are sticklebacks a model organism?
The threespine stickleback is an appropriate model organism for studying the effects of host genetic background on microbial community because wild populations exhibit genetic variation that is comparable to that of human populations.
Why are sticklebacks good for studying evolution?
Scientists have pinpointed mutations that may help a tiny armoured fish to evolve quickly between saltwater and freshwater forms. In as few as ten generations — an evolutionary blink of an eye — marine sticklebacks can swap their armoured plates and defensive spines for a lighter, smoother freshwater form.
How does a stickleback survive?
Summary: Stickleback fish are able to adapt their vision to new environments in less than 10,000 years, a blink of the eye in evolutionary terms, according to new research.
How did do the sticklebacks defend themselves from their predators?
During the end of the last ice age, retreating ice sheets created many new lakes, some of which were colonized by stickleback fish. For example, spines and armor protect stickleback from predatory fish, such as trout, whereas spines can make stickleback more likely to be caught by some insect predators.
What 3 things have changed in the stickleback fish over time?
In freshwater, they faced weaker but faster predators, so they lost their spines and armour and became smaller and more agile. Their lifestyles, colour, mating habits, salt tolerance and diets also changed.
How do sticklebacks survive in ponds?
ECOLOGY: This stickleback is well able to cope with osmoregulation (regulating its water content). It has tough spines on the back to protect it from be eaten by larger fish; As the predator tries to swallow them the stickleback raises the spines which get jammed in the throat. All the predator can do is spit them out.
What is the purpose of stickleback armor?
Sticklebacks use movable spines and fixed plates to provide stability and flexibility in withstanding impacts.
Why did the stickleback fish migrate to freshwater?
Three-spined stickleback populations are also found in freshwater lakes and streams. These populations were probably formed when anadromous fish started spending their entire lifecycle in fresh water, and thus evolved to live there all year round.
How are Lake sticklebacks different from Ocean sticklebacks?
One difference is the amount of protective armor that covers their bodies: while oceanic sticklebacks have about 30 armor plates extending from head to tail, most freshwater sticklebacks have just a handful of plates that sit closer to the front of the body.
Which of the following best explains the changes in the phenotype frequencies of the stickleback population in Loberg Lake?
2018 (17): Which of the following best explains the changes in the phenotype frequencies of the stickleback population in Loberg Lake? Predation in the marine environment is different from predation in Loberg Lake. The population of sticklebacks in Loberg Lake is subject to genetic drift.
What characteristics of stickleback fish make them ideal for studying natural selection in the wild?
What characteristics of stickleback fish make them ideal for studying natural selection in the wild? Stickleback populations are in environments with or without predators. Heritable variation in armor directly affects the fitness of sticklebacks. Some stickleback populations are isolated in closed environments.
Where are the sticklebacks that he refers to found?
Stickleback, any of about eight species of fishes in five genera of the family Gasterosteidae (order Gasterosteiformes) found in fresh, brackish, and marine waters in temperate regions of the Northern Hemisphere as far north as the Arctic Ocean.
What is the same about many freshwater stickleback populations worldwide?
The researchers found that, over most of the genomes, freshwater sticklebacks were most similar to their nearest ocean-dwelling neighbours. But in about 150 DNA sequences, freshwater and saltwater populations were each more like their counterparts in the same environments across the globe.