Describes the courtship behavior of the male cichlid.

QUESTION POSTED AT 26/03/2020 - 03:27 PM

Answered by admin AT 26/03/2020 - 03:27 PM

Using underwater microphones called hydrophones, researchers found that males would make low-frequency sounds when confronted with receptive females. And females preferred males associated with playbacks of these courtship sounds over males that were associated with no sound, or a neutral noise. Subordinate males were also subtly more sensitive to certain frequencies than dominant males. Although the reasons for this change are less clear, Studier suggests the subordinate males may "use the frequency of the sound to determine which males to fight with and attempt to take over their territory." Because the frequency of the courtship sound is related to body size, subordinate males may listen to these courtship sounds to identify the smallest – and most vulnerable – males in their area.
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Related questions

An example of natural selection is the tail of a male peacock. The females of the species choose mates based on the colors of the males’ tail feathers. If females begin using different criteria than feather color when they choose mates, what would most likely happen to the tails of peacocks over time? increased variation in tail feather color because the selection pressure has been relieved increased variation in tail feather color because the peacocks try different ways to impress the females decreased variation in tail feather color because no form of the trait is advantageous decreased variation in tail feather color because the only reason for variation was selection pressure


The correct answer is option D, decreased variation in tail feather color because the only reason for variation was selection pressure


According to Charles Darwin, traits that help an individual in selecting mates are favored by the sexual selection while all other normal traits are favored by natural selection.Thus , it is believed that this sexual mating pressure among the male peacocks produce large variation in the color and pattern.The male peacocks compete with each other to attract the female on the basis of their colorful tails and its varied patterns.

ANSWERED AT 29/03/2020 - 11:15 PM

QUESTION POSTED AT 29/03/2020 - 11:15 PM

Consider this northern site of primary succession following the retreat of a glacier. As we move from left to right, describe some improvements in the abiotic factors that support plant growth. A) change in climate over time B) less competition for water resources due to biodiversity C) improved soil quality: increased humus and water retention D) increased population density resulting in decreased pathogens

Answer: C. improved soil quality: increased humus and water retention.


An ecological succession brings change in the type of living species residing in an ecosystem with respect to changes that occur in the abiotic (non-living factors) with respect to time.

A region affected by a retreating glacier will not be suitable for the growth of living species. The soil may be lacking minerals and will be in the permafrost condition. So for the initiation of succession the improvement in soil an important abiotic factor is required. The improved soil quality will allow the accumulation of organic and inorganic minerals by physical and biological processes. This will help in formation of humus and water retention.

ANSWERED AT 28/03/2020 - 12:55 PM

QUESTION POSTED AT 28/03/2020 - 12:55 PM

Describe how hibernation has helped bear species survive. Compare the needs of the organisms to the traits.

It's helps them survive throughout winter and thrive without food during winter too. Before they go into hibernation they consume a large amount of food which helps their heartbeat slow down. Other animals that don't hibernate have their source of food during the winter too, which is the reason why they don't hibernate.

ANSWERED AT 28/03/2020 - 12:27 PM

QUESTION POSTED AT 28/03/2020 - 12:27 PM

Sort the phrases into the appropriate bins depending on which type of postsynaptic potential they describe. If a phrase describes both types of potentials, drag it to the "both" bin.

Excitatory postsynaptic possibilities (EPSPs) are excitatory in light of the fact that they make the postsynaptic neuron more prone to produce an activity potential by depolarizing the layer (making the film potential less negative) and conveying the layer potential more like an edge. This is regularly expert by opening ligand-gated Na+ diverts in the postsynaptic layer, which enables Na+ particles to enter the cell. 
Interestingly, inhibitory postsynaptic possibilities (IPSPs) make it more troublesome for the postsynaptic neuron to create an activity potential by hyperpolarizing the layer (making the film potential more negative) and moving the film potential more distant from the limit. This is frequently proficient by opening ligand-gated K+ directs in the postsynaptic layer, which enables K+ particles to leave the cell. 
Despite whether they are excitatory or inhibitory, all postsynaptic possibilities are reviewed, implying that their sizes are variable. (Activity possibilities, then again, are all-or-none occasions.) And on the grounds that a postsynaptic potential is not proliferated like an activity potential, its greatness diminishes with separation from the neurotransmitter along the cell body.

ANSWERED AT 28/03/2020 - 12:22 PM

QUESTION POSTED AT 28/03/2020 - 12:22 PM

A recipe gives the instructions below. After browning the meat, pour off the fat from the pan. To further reduce fat, use a strainer. What type of separation methods are described in the recipe? A. decantation and screening B. distillation and screening C. decantation and centrifugation D. distillation and filtration

Based on the given instruction above, I can say that the separation methods that are being used in the recipe are DECANTATION AND SCREENING. The answer would be option A. When we say decantation, this is a process of separating liquids in order to remove the layer of liquid that has precipitates in order to produce a cleaner product. Hope this helps.

ANSWERED AT 28/03/2020 - 12:05 PM

QUESTION POSTED AT 28/03/2020 - 12:05 PM

In a paragraph address these following questions: • How does an underwater earthquake cause a tsunami? • Why do some earthquakes cause more damage than others? the paragraph needs to also include the following things: • discuss how the different types of waves are formed and describe how the waves travel • explain how scientists use waves to track and analyze earthquakes • cover recent events involving earthquakes and/or tsunamis that illustrate the points made in your explanation

What is an Earthquake

Earthquakes are vibrations in the earth's crust They occur along all plate boundaries but are more destructive usually at destructive plate boundaries

How are they measured

The magnitude or size of an earthquake can be measured by an instrument called a seisometer and are shown on a seismograph. The earthquakes are measured on the Richter scale from a value of 1 to 10. Each level of magnitude is 10 times more powerful than the previous. Therefore a level 7 is 100 time more powerful than a level 5.

Why do some earthquakes cause more damage than others?

Some earthquakes take place in rural areas where few people live and little is damaged

If they occur near large urban areas with many people, transport services, large buildings and services such as gas and electricity - there can be a great amount of deaths and damage

In Poor countries - LEDC's they have poorly built buildings, few emergency facilities, and the equipment to help rescue people - a good term to use is that they have a poor infrastructure.

In rich countries - MEDC's such as the USA they prepare for an earthquake with drills and have a great deal of trained emergency personnel and equipment to go to help the injured. They also try to build to withstand earthquake damage - ie The Transamerica building

The time of day can be important - If the earthquake hits when it is the rush hour or when there is a large number of people located in a certain area - this can cause a great loss of life

Obviously if they occur near to coasts then Tsunamis can cause a great deal of damage and deaths such as the 2004 Boxing Day Tsunami

ANSWERED AT 28/03/2020 - 12:00 PM

QUESTION POSTED AT 28/03/2020 - 12:00 PM

describes estuaries?

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea

ANSWERED AT 28/03/2020 - 11:45 AM

QUESTION POSTED AT 28/03/2020 - 11:45 AM

Which list describes the path oxygen takes to the lungs? A. Larynx, trachea, pharynx, bronchi B. Trachea, bronchi, pharynx, larynx C. Pharynx, larynx, trachea, bronchi D. Bronchi, trachea, pharynx, larynx


The correct answer is option C.


The path of oxygen from the atmosphere to the lungs can be described from the nasal cavity to the alveoli. The oxygen is inhaled with air during the breathing process that travels from the nasal cavity to the pharynx that is tube or tract where mouth or oral cavity and nasal cavity combined. Oxygen moves from pharynx to the larynx and then to trachea or the windpipe.

The trachea is a tube that extended to the larynx to the 2 primary bronchi. Oxygen moves from the trachea to the bronchi. Bronchi are the main passage of oxygen to the lungs. Bronchi shuttle air to and from the lungs. These are of three types and oxygen travels into each in order first primary bronchi then secondary and in last to tertiary bronchi and bronchioles and ultimately to the site of gas exchange called alveoli.

Pathway - nasal cavities  > pharynx > trachea >bronchi (primary bronchi (right & left) > secondary bronchi > tertiary bronchi)> bronchioles > alveoli.

Thus, the correct answer is option C.

ANSWERED AT 28/03/2020 - 11:27 AM

QUESTION POSTED AT 28/03/2020 - 11:27 AM

Which of the following best compares the male and female reproductive structures of a gymnosperm? A Gymnosperms produce flowers, and the male stamens produce pollen that fertilizes the egg inside the female ovule. B Gymnosperms produce male cones and female cones, and the pollen from a male cone fertilizes the egg inside a female cone. C Gymnosperms have male sporangia and female archegonia, and spores fertilize eggs contained inside the embryo sac to form zygotes. D Gymnosperms exist as male and female gametophytes, and the male plant produces spores that fertilize eggs inside the female archegonia.

Answer: B Gymnosperms produce male cones and female cones, and the pollen from a male cone fertilizes the egg inside a female cone.  

Gymnosperms are terrestrial plants, which lacks flowers. The ovule or seeds are remains naked in hard woody structures called as cones. In the gymnosperms the green sporophyte generates cones that contains male and female gametophytes. A male cone consists of microsporophylls where male gametophyte also called as pollen are produced and released into the wind. The wind act as a agent for pollinating the female gametophyte present in the female cone.  Inside the female cone the megaspore mother cell produces four haploid megaspores, one megaspore divide itself to form the female gametopyte. The fusion of the pollen with the female gametophyte produces diploid zygote, which later on divides to form the embryo.

ANSWERED AT 28/03/2020 - 11:15 AM

QUESTION POSTED AT 28/03/2020 - 11:15 AM

describe how heredity can be illustrated mathematically

Heredity can be illustrated mathematically through the use of Punnets squares. Punnet squares give results as frequencies, probabilities of dominance of traits/characteristics  and the likes. The frequencies given are the to be calculated as to how many times the certain trait/characteristic occurs. It is also illustrated through the use of ratio, for instance, 3:5:1.

ANSWERED AT 28/03/2020 - 10:50 AM

QUESTION POSTED AT 28/03/2020 - 10:50 AM

Which correctly describes the mechanism of inheritance?

Nucleus & it's DNA material or simply anyone's DNA

ANSWERED AT 28/03/2020 - 10:48 AM

QUESTION POSTED AT 28/03/2020 - 10:48 AM

Describe one benefit and one limitation of how the trichoplax can reproduce by simple division

Trichoplax needs tissues, organs and any kind of symmetry. It is made out of just a couple of hundred to a couple of thousand cells. This life form has a straightforward upper and lower epithelium, which encompass a system of fiber cells, and in that capacity has an unpredictable, three-layered, sandwich-sort association. Just five diverse cell-sorts have so far been portrayed; upper and lower epithelial cells, organs cells, fiber cells and as of late found kind of little cells that are organized a generally equitably divided example inside the minor zone, where upper and lower epithelial meet.

ANSWERED AT 28/03/2020 - 10:19 AM

QUESTION POSTED AT 28/03/2020 - 10:19 AM

Describe a cellular division process that could be used by Trichoplax when it reproduces asexually.


Mitosis is the type of cell division that can be used by asexually reproducing organisms.


Mitosis is a sequence of events that, in the end, one cell, called the mother cell, gives rise to two other cells, the daughter cells. The main feature of mitosis is that daughter cells have the same number of chromosomes as the mother cell. Besides that,  no genetic recombination occurs during the process, that is, daughter cells are copies of the mother cell. Thus, this type of cell division is related to asexual reproduction, organism or colony growth and tissue regeneration.

Meiosis, in turn, is somewhat different. Although it is also a sequence of events, in meiosis the parent cell gives rise to four other cells. The main feature is that these four generated cells contain only half of the parent chromosomes. Thus, meiosis relates to the formation of gametes and sexual reproduction.

ANSWERED AT 28/03/2020 - 10:18 AM

QUESTION POSTED AT 28/03/2020 - 10:18 AM

Which of the following describes a positive feedback loop?

A positive feedback loop is one that tends to enhance an unstable situation out of equilibrium with its' state whereas a negative feedback loop tends to maintain a state close to equilibrium.

ANSWERED AT 27/03/2020 - 10:10 AM

QUESTION POSTED AT 27/03/2020 - 10:10 AM

Which best matches a list that a scientist would make to describe a forest ecosystem

You aren't showing us the answer choices, so we can't help 

ANSWERED AT 27/03/2020 - 09:49 AM

QUESTION POSTED AT 27/03/2020 - 09:49 AM

Which term is used to describe objects that are visible because of reflected light?

Would it be "illuminated?"

ANSWERED AT 26/03/2020 - 03:28 PM

QUESTION POSTED AT 26/03/2020 - 03:28 PM

Describe two ways in which an earthworm's body is adapted to life in the soil

They r able to dig down by eating soil,  then eliminating them through the anus
their digestive system is  able to break down decomposing plants, that is a common source of organic materials in the soil

ANSWERED AT 26/03/2020 - 02:22 PM

QUESTION POSTED AT 26/03/2020 - 02:22 PM

Hemophilia, color blindness, and duchenne muscular dystrophy occur more often in males than females. why? a these traits are carried only on the x chromosome and since there is no matching gene on the y chromosome, the traits are expressed more readily in males. b these traits are carried only on the x chromosome. c testis-determining factor (tdf causes these diseases. d these diseases develop due to the lack of estrogen and progesterone. e since there is no matching gene on the y chromosome, the traits are expressed more readily in males.


a) these traits are carried only on the x chromosome and since there is no matching gene on the y chromosome, the traits are expressed more readily in males.


Hemophilia, color blindness, and duchenne muscular dystrophy are disorders which are caused by X-linked recessive mutations which means that even if a mutation occurs in a gene of only one X chromosome then the phenotype will be expressed in the males because they are hemizygous for the gene. By hemizygous we mean to say that males have one X and one Y chromosome so a gene present on X chromosome will not find match on the Y chromosome and the mutation will express readily.

In contrast to this, in case of females who have two X chromosomes, the mutation in one X chromosome may be suppressed by another X chromosome in heterozygous condition i.e. if another X chromosome has healthy gene (wild type gene). In case of females the diseased phenotype will only appear if they are homozygous for the mutation.

ANSWERED AT 26/03/2020 - 02:06 PM

QUESTION POSTED AT 26/03/2020 - 02:06 PM

List the two groups of muscles in the body and describe how they are controlled

The types are smooth and rough.
smooth muscles are controlled by your brain, not you (digestion, circulation).
rough muscles are controlled by you (moving your leg)

Hope this helps!

ANSWERED AT 26/03/2020 - 01:58 PM

QUESTION POSTED AT 26/03/2020 - 01:58 PM

Describe how water’s unique properties helps a polar bear to survive. Include each of the properties of water and how each of these properties are helpful for the polar bear.

the very basic properties of water

conducts heat

neutral pH

high surface tension

high specific heat

good solvent

how does this help a polar bear, some of it is a stretch but possible benefits

pH - good drinking water, good for marine ecosystem for food

high specific heat - can absorb lots of heat before the temperature rises, polar bears exist naturally in cold environments. (ice) - maybe can tie this in with the natural hibernation cycle

high surface tension - I'm assuming the polar bear walks on the ice at times to get fish

as a good solvent - its probably good that most things dissolve in water, otherwise we would have a lot of floating gunk on top of the water

outside of this, can't give you much more. it has been noted in Shishmaref Village that the ice caps melting is leading to a lack of water in higher mountain areas and polar bears are coming down from the mountain ice cap areas to find food and water

ANSWERED AT 26/03/2020 - 01:33 PM

QUESTION POSTED AT 26/03/2020 - 01:33 PM

Which statement correctly describes the process that occurs in the thylakoid?

ATP is produced in the thylakoid during light-dependent reactions is the answer to your question

ANSWERED AT 26/03/2020 - 12:54 PM

QUESTION POSTED AT 26/03/2020 - 12:54 PM

DESCRIBE the characteristics of the four zones found in the ocean

Intertidal zone

The intertidal zone is the area of the seafloor between high tide and low tide. It bridges the gap between land and water. Tide pools, estuaries, mangrove swamps and rocky coastal areas are all part of the intertidal zone.

Neritic zone

The water above the continental shelf is the neritic zone. Underwater forest of kelp and grassy meadows of sea grass are home to tiny fish, green turtles, sea cows, seahorses and tiny shrimp. Coral reefs have thousands of animals and plants that live in the waters of the neritic zone.

Open ocean zone

The open ocean zone lies beyond the continental slope and contains 65% of the water in the oceans. This zone is divided further into three subzones. The sunlit zone is where photosynthesis takes place. Plankton and jellyfish are drifters that inhabit this zone. Most animals living in the open ocean live in the sunlit zone.

Twilight zone

Below the sunlit zone is the twilight zone where some light penetrates the ocean to a depth of 3000 feet. Viper fish, firefly squid, and the chambered nautilus live in this zone. The midnight zone extends from a depth of 3000 feet to the seafloor. Animals found in this zone include the giant squid, deep sea hatchetfish and bioluminescent jellyfish.

ANSWERED AT 26/03/2020 - 11:44 AM

QUESTION POSTED AT 26/03/2020 - 11:44 AM

Describe how a cuticle could have evolved through natural selection

For you to understand the process we can say that the weak will die. If the animal or organism can't get food or find any it is naturally "selected" to die.So a Cuticle could have evolved like that. Hope tgis is useful 

ANSWERED AT 26/03/2020 - 11:42 AM

QUESTION POSTED AT 26/03/2020 - 11:42 AM