The Chordates - Chapter 30 Key Terms

Chordates - member of the phylum Chordata; animal that has, for at least some stage of its life, a dorsal, hallow nerve cord; a notochord; pharyngeal pouches; and a muscular tail

Notochord - long supporting rod that runs through a chordate's body just below the nerve cord

Pharyngeal pouches - one of a pair of structures in the throat (pharynx) region of a chordate

Vertebrae - animal that has a vertebral column or backbone

Fish  - aquatic vertebrate characterized by paired fins, scales and gills

Cartilage - strong connective tissue that supports the body and is softer and more flexible than bone

Amphibian - vertebrate that, with some exceptions, lives in water as a larva and on land as an adult, breathes with lungs as an adult, and has moist skin that contains mucus glands and lacks scales and claws.

The Chordates - Chapter 30 Assesment

1) c. 2) b 3) c 7) a
11) In most developing vertebrates, the notochord grows into the brain and hardens, turning into the spinal cord or backbone.
25) Two specialized structures that give amphibians movement are legs and fins. An example of legs would be a frog's hind legs that allow them to jump. An example of a fin would be the fins on a salamander that help them move through the water in an S-shaped pattern.
28) The world-wide decline of amphibian populations could be related to two of their prominent characteristics - Their skin is thin and must be kept moist and their eggs have no shell and must be kept moist. Global warming is reducing the amount of water that amphibians can use.

The Chordates - Amphibians

An amphibian is a vertebrate that with some exceptions lives in water as a larva and on land as an adult, breathes with lungs as an adult, has moist skin that contains mucus glands and lacks scales and claws. 

Early amphibians evolved several adaptions that helped them live at least part of their lives out of water. Bones in the limbs and limb girdles of amphibians became stronger, permitting more efficient movement. Lungs and breathing tubes enabled amphibians to breathe air. The sternum or breastbone, formed a bony shield to support and protect internal organs, especially the lungs.

• Feeding - Tadpoles are filter-feeders or herbivores that graze on algae. They turn into carnivores, however when they reach adulthood and their digestive system is completely altered. 
• Respiration - Gas exchange occurs through the skin as well as the gills. Lungs replace gills when the creature reaches adulthood.
• Circulation - The circulation forms a double loop. The first loop carries oxygen-poor blood from the heart to the lungs and skin, and takes oxygen-rich blood from the lungs and skin back to the heart. The second loop transports oxygen rich blood from the heart to the rest of the body and oxygen poor blood from the body back to the heart. 
• Excretion - Amphibians have kidneys that filter wastes from the blood. 
• Reproduction - Many species of amphibians lay their eggs in the water and are fertilized externally. 
• Movement - For the most part, amphibians move much like fish. Frogs and a few others have developed hind legs for jumping. 
• Response - similar brain structure to a fish

Amphibians can be categorized in three groups. Salamanders, frogs/toads, and caecilians. 

Salamanders - Most have four legs. Are carnivores. Live in moist woods and tunnels, under rotting logs and rocks. Some live in water their whole lives. 

Frogs/Toads - They can jump. Frogs and toads lack tails as adults. Frogs typically live in and near water, while toads can survive in dry environments. 

Caecilians - Least known member! Legless creatures. They often live in water or burrow in most soil and feed on small invertebrates such as termites. 

The Chordates - Fishes

Fishes are aquatic vertebrates that are characterized by paired fins, scales and gills.

• Fins are used for movement
• Scales are used for protection
• Gills are for exchanging gases

Fishes were the first vertebrates to evolve. They did not arise directly from tunicates or lancelets, but fishes and nonvertebrate chordates probably did evolve from common invertebrate ancestors. During the course of their evolution, fishes underwent several important changes. 

The evolution of jaws and the evolution of paired fins were important developments during the rise of the fishes! 

The earliest fishes to appear in the fossil record were odd-looking, jaw-less creatures whose bodies were armored with bony plates. 

The Devonian Period, which is often called the Age of fishes. Fish underwent a major evolution at this point. Jaw-less fishes emerged at this points. Unlike their ancestors, they had very little armor. 

The evolution of jaws in early fishes accompanied the evolution of paired pectoral and pelvic fins.  The fins were attached to structures of cartilage or bone that supported the fin. Paired fins gave fish greater movement and jaws gave them a wider diet. 

Although the early jawed fishes soon disappeared they left beyond two groups that continue to evolve and survive today. One group - the ancestors of modern sharks and rays - evolved a skeleton made of strong, resilient cartilage. The other group evolved skeletons made of true bone. A sub-group of bony fishes called lobe-finned fishes have fleshy fins from which the limbs of chordates would later evolve. 

Adaptions to aquatic life include various modes of feeding, specialized structures for gas exchange, and paired fins for locomotion. 

• Feeding- every type of feeding from herbivores, carnivores and omnivores 
• Respiration - Most fishes exchange gases using gills located on either side of the pharynx. The gills are made up of feathery threadlike structures called filaments. Each one contains a network of fine capillaries that provides a large surface area for the exchange of oxygen and carbon dioxide. Fishes that exchange gases using gills do so by pulling oxygen-rich water in through their mouths, pumping it over their gill filaments, and then pushing oxygen-poor water out through the openings in the sides of the pharynx. 
• Circulation - Fishes have closed circulatory systems with a heart that pumps blood around the body in a single loop from the heart to the gills from the gills to the rest of the body, from the gills to the rest of the body and back to the heart. 
• Excretion - Like many other animals, most fishes rid themselves of nitrogenous wastes in the form of ammonia. Some wastes diffuse through the gills into the surrounding water. Others are removed by kidneys, which are excretory organs that filter wastes from the blood. 
• Response - Most fishes have highly developed sense organs. Almost all fishes that are active in daylight have well-developed eyes and color vision that is as good as the average human. They have extraordinary senses of taste and smell an can detect motion although they cannot hear very well. 
• Movement - Most fishes move by alternating contracting paired sets of muscles on either side of the backbone. This creates a series of S-shaped curves that propels the fish through the water. 
• Reproduction - The eggs of fishes are fertilized either externally or internally, depending on the species. Those that hatch outside of the mother are called oviparous. Those who are "born alive" are called viviparous. 

When you consider their basic internal structure, all living fishes can be classified into three groups, jaw-less fish, cartilaginous fishes and bony fishes. 

Jaw-less fishes - They have no true teeth or jaws. Skeletons are made of fibers and cartilage and they lack vertebrae. They keep their notochord as adults. They are two types - lampreys and hagfishes. 

Cartilaginous Fish- This group contains sharks and their relatives. 

Bony Fishes- These fishes are made of hard, calcified tissue called bone. Almost all of them are ray-finned. 

Some fishes spend most of their lives in the ocean but breed in fresh water. They are called anadromous. Others live in fresh water but migrate to salt water to breed. These fishes are called catadromous. 

The Chordates - An Introduction

Fish, Amphibians, reptiles, birds and mammals are all very different but are all members of the phylum Chordata.
Members of the phylum Chordata are called chordates. To be classified as a chordate and animals hash to have four key characteristics.
A chordate is an animal that has or had for some stage of life, a dorsal, hallow nerve cord; a notochord; pharyngeal pouches and a tail that extends beyond the anus.
The hollow nerve cord runs along the dorsal (back) part of the body. Nerves branch from this cord at regular intervals and connect to the internal organs, muscles, and sense organs.
The notochord is a long supporting rod that runs through the body just below the nerve cord. Most chordates have a notochord only when they are embryos
Pharyngeal pouches - These are paired structures in the throat (pharynx) region. In some chordates - such as fish and amphibians - slits develop that connect the pharyngeal pouches to the outside of the body. These slits may then develop into gills that are used for gas exchange.

At some point in their lives, all chordates have a tail that extends beyond the anus. The tail can contain bone and muscle and is used in swimming by many aquatic species.

Most Chordates are vertebrates. More than 99% of them are in the subphylum Vertebrata and are called vertebrates. A vertebrate is a chordate that has a strong supporting structure called a backbone. IN vertebrates, the dorsal, (hollow nerve cord) is called the spinal cord. The front end is in the brain. It IS the backbone and replaces the notochord in most developing vertebrates and is made of small individual segments called vertebra.

However, there are SOME nonvertebrate chordates. The two groups of nonvertebrate chordates are tunicates and lancelets. Both are soft-bodies marine organisms. They have a hollow nerve cord, a notochord, pharyngeal pouches, and a tail.
Tunicates are filter-feeding organisms that look a bit like tubes. Lancelets are small and fish-like creatures that live on the sandy ocean bottom.

Orange Cupcake Project

        
 27 million people worldwide are victims of the monstrosity we know as human slavery, or trafficking. This is a tragedy against mankind. Men, women and children are held against their will and forced to work in uncomfortable conditions and often physically and sexually assaulted. They are stripped of their identities and treated worse than animals. Often food is withheld from them. How do people become victims of human slavery? Parents sell their children, people become indebted and are forced to become slaves, others are tricked, sometimes, it happens because of war, and other times people are kidnapped or have their lives threatened. There are a variety of causes to this great crime against humanity. No matter the cause, the victim in the incident would need to be rescued and healed from this traumatic event. Slavery is NEVER okay. This is because God created every one of his children equally and wonderfully. Any human who thinks they are more important or superior to another one of God's children is terribly mistaken and committing the sin of pride. Slavery has no place in this world. Unfortunately, people all over the globe are terribly confused about this. As a Christian, it is my job to spread God's truth. That's why I have to do this. My goal is to raise $3,333.33. I plan on doing this by selling cupcakes and orange clothing/accessory products. Why orange? Orange is the color of freedom. It's a color of possibility and determination. It's not the prettiest color, but it IS an honest color. It's stubborn and it doesn't give up. I plan on making headbands, t-shirts and bandannas that are orange and have the word "FREEDOM" in caps stenciled across the front. I'll give all the profits to charitable organizations dedicated to ending slavery. Updates will follow!

Social Security

IM CUTE. DONT STEAL FROM ME. 

Social Security News Flash: If things keep running like they are, the Social Security fund will either be gone away with or depleted. Pick one. It needs to be fixed and FAST! 

In order to fix it, three things need to happen -

• Increase Revenue going into the Social Security Fund
• Decrease Benefits
• Keep the money CONTROLLED and going ONLY to the seniors and disabled people who NEED it. As in, it's not the goverment's checkbook. KEEP YOUR HANDS OFF MY SOCIAL SECURITY MONEY, LOSERS!

Obviously, some Congress people, for whatever reason, see issues with these simple steps. It's elementary, you morons. 

Who's gonna be effected if we don't fix Social Security? Cute little kids like the ones in the above picture! Anyone who isn't gonna be retired by 2020. People who are gonna be paying INTO the failing system, yet not getting anything out of it. 

Why do we have social security problems? Two reasons

• The Baby Boomers - Right after WWII ended, lots of soliders came home to their otherwise non-pregnant wives. You put the pieces together.
• Abortion - Because the darn baby boomers legalized abortion, the population has a huge lump in it and not very many kids are being born anymore. This means less people to pay into the system. This is really tough, because we have a HUGE lump of people to support. How is Gen Y supposed to take care of the Boomers, the BIGGEST age group when they majority of them were killed in the womb? ARGH! It's just not cool

The "decade" when the Boomers were the most impressionable was the 60s. GREAT. Jusssst great. The sixties were the "irresponsible and DANGEROUS" years. All we need is a bunch of crazy seniors who had a ton of abortions. Yup, that's ALL we need. 

They dug a nice great pit, but they are all gonna die before they actually fall into it. We have to patch it up quick or we'll all die!