Small fish: Big role in coastal carbon cycle! Developmental Biology!

Small fish: Big role in coastal carbon cycle








This study talks about how small habitats transform carbon dioxide from the atmosphere into the ocean which cause global warming. this is short paragraph from the website to see and you can also visit the above website for more information to see how it happen:

"Oct. 18, 2012 — A study in the current issue of Scientific Reports, a new online journal from the Nature Publishing Group, shows that small forage fish like anchovies can play an important role in the "biological pump," the process by which marine life transports carbon dioxide from the atmosphere and surface ocean into the deep sea—where it contributes nothing to current global warming.
The study, by Dr. Grace Saba of Rutgers University and professor Deborah Steinberg of the Virginia Institute of Marine Science, reports on data collected during an oceanographic expedition to the California coast during Saba's graduate studies at VIMS. Saba, now a post-doctoral researcher in Rutgers' Institute of Marine and Coastal Research, earned her Ph.D. from the College of William and Mary's School of Marine Science at VIMS in 2009. The expedition, aboard the research vessel Point Sur, was funded by the National Science Foundation.
The study's focus on fish is a departure for Steinberg and colleagues in her Zooplankton Ecology Lab, who typically study tiny crustaceans called copepods. Research by Steinberg's team during the last two decades has revealed that copepods and other small, drifting marine animals play a key role in the biological pump by grazing on photosynthetic algaenear the sea surface, then releasing the carbon they've ingested as "fecal pellets" that can rapidly sink to the deep ocean. The algal cells are themselves generally too small and light to sink.
"'Fecal pellet' is the scientific term for "poop," laughs Steinberg. "Previous studies in our lab and by other researchers show that zooplankton fecal pellets can sink at rates of hundreds to thousands of feet per day, providing an efficient means of moving carbon to depth. But there have been few studies of fecal pellets from fish, thus the impetus for our project."

Refrences:

www.macroevolution.net/marine-carbon-cycle.html

The Element of Ecology! Topic: Factors affecting birth rate!

What is birth rate? According to wikipedia, ' The birth rate is typically the rate of births in a population over time. The rate of births in a population is calculated in several ways: live births from a universal registration system for births, deaths, and marriages; population counts from a census, and estimation through specialized demographic techniques.' 

Factors affecting birth rate as follow:

1. Government policy: Government policy affect birth rate, for example is pronatalist or antinatalist ( tax on childlessness).
2. Availability of family planning such like, birth control and sex education among the communities.
3. Safety abortion and safety child birth in the community.
4. Illiteracy and unemployment factors can affect birth rate.
5. High poverty level within the nation can affect birth rate.
6. Long term economic difficulty can affect birth rate, because married couple that is facing financial problem tend to delay child bearing for some reason. 
7. Religious and social belief can affecting birth rate, in term of abortion and contraception. 

References:
www.wikipedia.com 

Developmental Biology! The Cycle of Life.

The generalized life cycle in animal is one of the major triumphant  descriptive of embryology and each  animal, whether frog, human being or others has a similar stages of development. The stages of development between fertilization and delivery or hatching are uniformly called 'EMBRYOGENESIS.'





Embryonic has a six fundamental processes and we will mention as follow below:

1. Fertilization: this involves the fusion of the matured male and female sex cells and they are collectively called gametes. once the fertilization occurred, it stimulate the development of the egg into initial new specie and continue to the next stage called cleavage.

2. Cleavage is a continuous rapid mitotic divisions that immediately follow after fertilization and during this cleavage, mass number of zygote cytoplasm is divided into smaller cells called Blastomeres. At the end of cleavage formed the a sphere called blastula.

3. Gastrulation: After the fast rate of mitotic cell division slow down, the blastomeres undergoes a rearrangement of position relatives to one another. And the series of cell rearrangement is called gastrulation and at this stage, the embryo is called gastrula stage which this stage of gastrulation result to three germ layers that interact with each other to form organs of the body.

4. Organogenesis: Once the three germ layers is finally established, the cells interact with one another and rearranged themselves, then they produce tissues and organs; and the process is called organogenesis.

5. In some species, the organism that hatches from the egg is not sexually mature, but rather, the organism need to undergoes metamorphosis to become a sexually mature adult. According to wikipedia, 'Metamorphosis is a biological process by which an animal physically develop after birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation."

6. in many species, the group of cells are put aside to formed the next generation. These mentioned cells are the precursors of the gametes. The germ cells are the collectively of the gametes and their precursor and they are set aside for productive physiology and others cells of the body are somatic cells. The separation of the somatic cells give rise to the individual body and the germ cells contributes to new generation.

References:

www.wikipedia.com
Developmental Biology ninth edition, by Scott F. Gilbert.

Ecology! Soil Profile!

SOIL PROFILE PICTURE BELOW:


  





Soil profile is also know as soil horizon and according to wikipedia definition, " A soil horizon is a layer parallel to the soil surface, whose physical characteristics differ from the layers above and beneath. Each soil type has at least one, usually three or four horizons. Horizons are defined in most cases by obvious physical features, chiefly colour and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. ‘coarser’ or ‘sandier’ than the horizons above and below."

1. The 'O' zone is the organic layer dominated by organic material consisting of un-decomposed or partially  decomposed plant material.
2. The 'A' zone is the topsoil and is largely mineral soil developed from parent material; organic matter leached from above gives this horizon a distinctive dark color.
3. The 'B' zones the subsoil and is accumulation of mineral particles, such as clay and salts leached from topsoil.
4. The 'C' zone is unconsolidated material derived from the original parent material from which the soil developedFinally, the collectively sequences of horizontal layers constitutes a soil profile and this pattern of horizontal layers is visible to see from fresh cut been made along a road bank for a building site.
References:
www.wikipedia.com
Element of Ecology Text Book.

Developmental Biology! Sex determination in Reptile.

                

Temperature dependent sex determination

See also: Temperature-dependent sex determination

Many other sex-determination systems exist. In some species of reptiles, including alligators, some turtles, the tuatara, sex is determined by the temperature at which the egg is incubated during a temperature sensitive period. There are no examples of temperature-dependent sex determination (TSD) in birds (including megapodes, which had formerly been thought to exhibit this phenomenon, but actually exhibit temperature-dependent embryo mortality).^[28] For some species with TSD, sex determination is achieved by hotter temperatures being one sex and cooler temperatures being the other. For others, the extreme temperatures are one sex and the middle temperature is the other. These temperature thresholds are known as Pattern I and Pattern II, respectively. The temperatures required for the specific sexes are known as the female promoting temperature and the male promoting temperature.^[29] When the temperature stays near the threshold during the temperature sensitive period, the sex ratio is varied between the two sexes.^[30] Some species set their temperature standards based on when an enzyme is created. These species that rely upon temperature for their sex determination do not have the SRY gene, but have other genes such as DAX1, DMRT1, and SOX9 that are expressed or not expressed depending on the temperature.^[29] Some species such as the Nile Tilapia, Australian skink lizard, and Australian dragon lizardhave sex determined by chromosomes, but this can later be switched by the temperature of incubation.^[9] These species seem to be in a transitional state of evolution.

It is unknown how exactly temperature sex determination evolved.^[31] It could have evolved through certain sexes being more suited to certain areas that fit the temperature requirements. For example, a warmer area could be more suitable for nesting, so more females are produced to increase the amount that nest next season. However, at this stage it's mostly hypotheses.

Other sex determination systems

While temperature dependent sex determination is relatively common, there are many other environmental systems. Some species, such as some snails, practice sex change: adults start out male, then become female. In tropical clown fish, the dominant individual in a group becomes female while the other ones are male, and bluehead wrasses (Thalassoma bifasciatum) are the reverse. In the marine worm (Bonellia viridis), larvae become males if they make physical contact with a female, and females if they end up on the bare sea floor. This is triggered by the presence of a chemical produced by the females, bonellin. Some species, however, have no sex-determination system. Hermaphrodites include the common earthworm and certain species of snails. A few species of fish, reptiles, and insects reproduce by parthenogenesis and are female altogether. There are some reptiles, such as the boa constrictor and komodo dragon that can reproduce sexually and asexually, depending if a mate is available.^[32] In the case of the boa constrictor, it can create both male and female offspring parthenogenetically.

In some arthropods, sex is determined by infection, as when bacteria of the genus Wolbachia alter their sexuality; some species consist entirely of ZZ individuals, with sex determined by the presence ofWolbachia.^[33]

Other unusual systems (this section is still being researched):

References:

www.wikipedia.com

Ecology! Environmental factors to human health.

According to the Environmental Protection Agency, cancer, cardiovascular disease, respiratory disease, infectious disease, and birth defects are all associated with exposure to environmental contaminants, and all occur in epidemic proportions in the U.S.
There are currently 85,000 chemicals on the market in this country – 20,000 more than were available in the 1970s – and only a few hundred have been tested for their safety. Lowering the levels of chemicals in our environment has the potential to lower rates of death and disease, and literally make us feel better.

According to the government agency (EPA), mentioned all these associated with environmental factors that prone health negatives to human being around the globe as followed below:

In the 42 years since Earth Day was founded, more attention has been brought to the dangers of pollution and global warming, to the importance of recycling, and the “green” lifestyle I’ve championed for decades. But a lot of other changes have occurred, many of them negative, most of them toxic, and nearly all of them preventable.
On Earth Day 2012, let’s consider some of these trends, how they have affected our health, and aim to make them obsolete.
Food derived from genetically modified organisms (GMOs) pervades the U.S. market because they resist pests and increase crop yields. These foods have had specific changes introduced to their DNA by engineering techniques, and include soybeans, corn, canola, rice, dairy, and more.
Such ingredients are hidden in nearly all processed foods, and can cause health concerns like allergies, antibiotic resistance, and liver problems. GMO foods can be avoided by purchasing 100 percent organic items, shopping locally, buying whole foods or growing your own food.
Babies are being born pre-polluted, meaning industrial chemicals have been found in umbilical cord blood – 200 on average, according to a 2009 report by the Environmental Working Group. In 2010, the President’s Cancer Panel at the National Cancer Institute noted that health officials still lack critical knowledge about the health impact of chemicals on fetuses and children.
The oceans now contain “dead zones,” which are parts of the sea floor along the coasts of major continents that have very low concentrations of oxygen. As a result, few organisms can survive there. According to NASA’s Goddard Earth Sciences Data and Information Services Center, the apparent cause of dead zones is fertilizer, which runs off fields, into streams, and eventually the ocean. Additionally, the North Pacific Ocean contains something called The Great Pacific Garbage Patch, two large masses of trash that scientists estimate is twice the size of Texas, and hazardous to marine life, fishing, and tourism. Recycling and proper trash disposal has never been more imperative!
The U.S. is replete with factory farms, which confine thousands of animals in awful, dirty circumstances and pump them full of antibiotics, all in the name of food production. Such farms generate huge amounts of manure containing deadly pathogens, antibiotics, drug-resistant bacteria, hormones, heavy metals, ammonia, and hydrogen sulfide that can seriously impact human health, as David Kirby details in his book Animal Factory. The activities on factory farms create massive amounts of pollution that harms the people living nearby, according to the Humane Society of the United States, not to mention what the meat from overfed, diseased animals can do to your body.

References:
http://voices.rodale.com/the-top-environmental-factors-affecting-your-health/2012/04/23/

Posted by Akinola on October 12, 2012.

Elements of Ecology! Factor affecting Climatic change.

What is climate? Climate is the long term average pattern of weather and may be local, regional, or global.

Factors affecting climatic change:

Distance from the sea (Continentality)

The sea affects the climate of a place. Coastal areas are cooler and wetter than inland areas. Clouds form when warm air from inland areas meets cool air from the sea.  The centre of continents are subject to a large range of temperatures.  In the summer, temperatures can be very hot and dry as moisture from the sea evaporates before it reaches the centre of the land mass.

Ocean currents

Ocean currents can increase or reduce temperatures. The diagram below shows the ocean currents of the world. The main ocean current that affects the UK is the Gulf Stream.

Click the map to see a larger version

The Gulf Stream is a warm ocean current in the North Atlantic flowing from the Gulf of Mexico, northeast along the U.S coast, and from there to the British Isles.

The Gulf of Mexico has higher air temperatures than Britain as it is closer to the equator.  This means that the air coming from the Gulf of Mexico to Britain is also warm.  However, the air is also quite moist as it travels over the Atlantic ocean.  This is one reason why Britain often receives wet weather.

The Gulf Stream keeps the west coast of Europe free from ice in the winter and, in the summer, warmer than other places of a similar latitude.

Direction of prevailing winds

Winds that blow from the sea often bring rain to the coast and dry weather to inland areas.  Winds that blow to Britain from warm inland areas such as Africa will be warm and dry.  Winds that blow to Britain from inland areas such as central Europe will be cold and dry in winter. Britain's prevailing (i.e. most frequently experienced) winds come from a south westerly direction over the Atlantic.  These winds are cool in the summer, mild in the winter and tend to bring wet weather.

The shape of the land ('relief')

Climate can be affected by mountains. Mountains receive more rainfall than low lying areas because as air is forced over the higher ground it cools, causing moist air to condense and fall out as rainfall.

The higher the place is above sea level the colder it will be.  This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. That is why you may see snow on the top of mountains all year round.

Distance from the equator

The distance from the equator affects the climate of a place. At the poles, energy from the sun reaches the Earth's surface at lower angles and passes through a thicker layer of atmosphere than at the equator. This means the climate is cooler further from the Equator. The poles also experience the greatest difference between summer and winter day lengths: in the summer there is a period when the sun does not set at the poles; conversely the poles also experience a period of total darkness during winter. In contrast, daylength varies little at the equator.

El Niño

El Niño, which affects wind and rainfall patterns, has been blamed for droughts and floods in countries around the Pacific Rim.  El Niño refers to the irregular warming of surface water in the Pacific.  The warmer water pumps energy and moisture into the atmosphere, altering global wind and rainfall patterns. The phenomenon has caused tornadoes in Florida, smog in Indonesia, and forest fires in Brazil.

El Niño is Spanish for 'the Boy Child' because it comes about the time of the celebration of the birth of the Christ Child. The cold counterpart to El Niño is known as La Niña, Spanish for 'the girl child', and it also brings with it weather extremes.

Human influence

The factors above affect the climate naturally.  However, we cannot forget the influence of humans on our climate.  Early on in human history our effect on the climate would have been quite small.  However, as populations increased and trees were cut down in large numbers, so our influence on the climate increased.  Trees take in carbon dioxide and produce oxygen.  A reduction in trees will therefore have increased the amount of carbon dioxide in the atmosphere.

The Industrial Revolution, starting at the end of the 19th Century, has had a huge effect on climate.  The invention of the motor engine and the increased burning of fossil fuels have increased the amount of carbon dioxide (a greenhouse gas - more on that later) in the atmosphere.  The number of trees being cut down has also increased, reducing the amount of carbon dioxide that is taken up by forests.

References:

All these information was extracted from the website below:

http://www.ecn.ac.uk/what-we-do/education/tutorials-weather-climate/tutorial-welcome/climate/factors-affecting-climate

Developmental Biology! Gametogenesis!

What is Gametogenesis? According to Wikipedia, ' is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.' 

Image of gametogenesis in male and female on left side.

References: 
wikipedia.com