Evolution of Nervous System


A marine flatworm


a type of flatworm


a fluke

About 13,000 species of flatwormstapeworms and flukes have nerves cells that located at anterior end of there bodies. Organisms in phylum Platyhelminthes were the first to have true nervous system.


Even though they have developed heads, they do not have real brains.  Two ganglia that run along ventral side of their are masses of nerve cells bodies.

The development of nervous system in those worms allow animals that evolved afterward to  take advantages of their surroundings.  Organisms can react with their environments.  This lead to adaptations to changes in their habitats or ecosystems.  Nerve cells from all parts of their bodies send signals to the brains and back to the parts. Organisms are able to function more with the development. Their organs have to work together to reproduce required response.

For an example, nervous system allow animals to feel plain and uses their muscles to run away.  They breathe faster as their brains need more oxygen. Infilepicker-uVI2i3Te2A8n7578IRlQ_predator_chase copy  a flight or fight situation, their brains will shut down digestive system to send more blood to the muscles and internal organs.  Sensors tell their brains to cool off the bodies when they are over heating  as they run.

Without nervous system, the animals would be dead.  Their bodies would not function the way they should. Being motionless will not help them in any way.  Preys would not be able to run from predators, they will not be able to move or even to  take in oxygen.


The Aquarium Tour and the Kayak Trip

It was last week when my marine science class went to the Shaw Discovery Ocean Centre, our local aquarium to take a good look on what we have been learning.  We also  went on a kayak trip in Brentwood Bay to observe the organisms in our ecosystem, well pretty much to ‘examine’ our environments.

tumblr_mr62ceUEtg1s4bdezo1_500It felt nice to be at the aquarium.  When I was a little girl, I had always enjoyed visiting the aquarium at a university back in Thailand.  I went there so often that my parents made a joke that all creatures there remember me.  Now that I am older, marine organisms became more interesting and beautiful.


original colour

Seeing a Giant Pacific Octopus changing its colour from redish-brown to partually white was so cool.  click here! to see what I saw 🙂 It knows how to open a lid of plastic container.


after it turned white


what a beautiful sea pen!

One of my favorite marine invertebrate must be the sea pens.  They are one of the organisms that decorate the ocean flow when they glow in the dark.

I had a chance to touch starfishes and sea anemones for the first time. The green sea anemones tentacles are surprisingly sticky as their tentacles are fairly small.  Green_Sea_Anemone_by_dgillies

I would love to go back to the aquarium again!



Last marine science feild trip started off pretty scary.  It was the first time I have kayaked.  All of my classmate wanted to go on the single-person kayak, that made me even more alarming. However, one of them was kind enough to go on the double with me.  I used to thought that being in a kayak must be uncomfortable , I was wrong.  Controlling the rudder was not easy.  We hit the same dock for about 3 times.  Despite the difficulties, the whole trip was delightful.  I saw LOTS of white jellies along the big rocks  or shores where the water was shallow.  We were lucky enough to witness a seal swimming around.  On our way back, my kayak was the last to get back….well well.  Everyone was so support and encouraging.  What a lovely bunch of people! haha:D

Adaptations in Marine System

Oceans can be very difficult to live in.  It is important to marine organisms to adapt to changes in their environments.  They have to deal with salinity, water movement and many more problems.


Salinity or the level of salt in seawater various through out the world.  Saltiness of oceans can level from 3% to 4%, or it can increase to40%.  Living things in oceans are adapt to maintain the amount of salt in their bodies at a constant level to keep their metabolisms working properly.  All kind of fish or sea creatures must learn how to regulate salt that they intake in order to survive.  for example, fish eliminate the salt through their gills, seabirds eliminate the salt via the nasal or sneeze out by the birds.  Even though a lot of them take great care to maintain the proper balance of water and salt within their bodies, many marines organisms are still affected by changes in the level of salinity.

Some said level salinity affects the whole ecosystem.

Movement of water come in forms of waves, tides and currents.   Waves caused by wind acting on the surface of the sea can be very destructive; however, they also cleanse organisms and help to increase oxygen availability.

Ocean_Tides some organisms are able to resist drying out during low tide that caused from forces of the moon and the sun interacting.


Currents can move food resources and nutrients from the coastline farther out into the ocean.  The species in the area might migrate to somewhere else. Different characteristics in the population may help some individuals win the competition to survive and reproduce. They also rely on currents to transport their eggs and larvae.

Many marine invertebrates and plants have the ability to cling on to rocks or other substrates so they are not washed away.

afterlight copy

The Ocean Study

biodiversity2Marine scientists are using all kinds of sciences to help them understand and study the ocean world. Learning about marine organisms required biology,  knowing the chemical properties in the ocean involve chemistry and climatology relates to the study of the  climate affecting the water are some examples.   Oceanography covers wide range of topics, from marine organisms to plate tectonics and the geology of the ocean floor.

Both biotic and abiotic factors influence each other.  If one factor in an ecosystem change, perhaps by pollution or natural phenomenon, the whole system can be alter or disrupt.  Health of the oceans are more important than we think.  They cover 71% of the world and  is home for almost all living matters.  The effects of climate changing on ocean animals are more visible everyday.  The increase in average temperature of the atmosphere and the ocean cause from humans’ actions – greenhouse gases – or from the nature itself, such as Earth’s orbit around the Sun, solar activity, and volcanic emissions.image_gallery

One of the most dramatic change in the ocean from climate changing is coral bleaching. Coral reefs can only tolerate a narrow temperature, high temperature water lead to their death. They provide a home for at least 25% of the marine organisms.
However, it is found that Eilat’s corals have better chance of survival than other sites.


Many fish can change sex during their lifetime! Especially rare deep-sea fish, have both male and female sex organs.