Vertebrate Anatomy PHYLUM CHORDATA BUT FIRST TAXONOMY Classification

Vertebrate Anatomy PHYLUM CHORDATA

BUT FIRST…. TAXONOMY Classification of Life • The science of classifying organisms is called: TAXONOMY • This classification system allows us to do 2 things: • 1) Identify organisms • 2) Provide a basis for recognizing natural groupings of living things

Levels of Classification • Carolus Linnaeus (1700’s) developed a system of classification based on an organism’s physical and structural features • The more features an organism has in common the closer the relationship

7 Levels of Classification Dumb Kings Play Chess On Fine Grained Sand Domain Kingdom Phylum Class Order Family Genus Species These are 7 main levels of taxa

Binomial Nomeclature When assigning names to organisms we use binomial nomenclature: A two part latin name used to assign names to organisms commonly known as the scientific name uses genus and species name • Genus is capitalized, both words should be italicized • Humans- Homo sapiens Domestic Dogs- Canus lupus • Domestic Cat- Felis catus •

Ok , Back to Vertebrates Recall: Vertebrates are animals that have backbone (an endoskeleton) Make up 5% of animal diversity Other 95% = Invertebrates Vertebrates a include: fishes, amphibians, reptiles, birds, and mammals

Refresher Questions 1. Which of the following terms describes all animals? A- unicellular and heterotrophic B- multicellular, autotrophic and heterotrophic C- eukaryotic, multicellular and heterotrophic

2. Radial symmetry is… A- the kind where only one plane can divide the body into equivalent parts B- any plane that passes through the center of the object forms two identical mirror images C- all planes passing through central axis (usually vertical) divides the form into two identical mirror images

3. Which kind of symmetry is found in the most advanced animals? A- radial B- bilateral C- spherical D- assymetrical

4. Some animal have body cavities that are not lined by mesoderm. These animals would be called: A- Acoelomate B- Pseudocoelomate C- Coelomate

5. Out of the three germ layers, which of the layers is responsible forming the circulatory, respiratory and urinary systems of an organism? A- ectoderm B- mesoderm C- endoderm D- dermis

Phylum Chordata

What is a chordate? Animals belonging to Phylum Chordata are called chordates. Phylum Chordata has 45000 species. Animals belongind to this phylum include mammals, fishes, amphibians, reptiles & birds All Chordates MUST have four key characteristics. These characteristics need not be present during the entire life cycle Dorsal, Dorsal hollow nerve cord notochord Pharyngeal Tail pouches

Tail A tail that extends beyond the anus. All chordates have this at SOME point of life cycle. The tail can contain bone and muscle and is used in swimming by many aquatic species.

Pharyngeal Slits Paired structures in the throat (pharynx) region Some chordates (fishes and amphibians) slits develop that connect the pharyngeal slits to the outside of the body These slits then develop gills that are used for gas exchange Other chordates, like mammals, pharyngeal slits found only in embryonic stage of development In humans these become eustachian tubes, tonsils, thymus and parathyroids

Notochord Flexible, Runs long supporting rod through the body just below the nerve cord Most chordates have a notochord only when they are embryos Derived from mesoderm and develops into connective tissue Is replaced by vertebral column in adult vertebrates

Dorsal Hollow Nerve Cord Hollow nerve cord runs along the dorsal (back) part of the body Derived from ectoderm and will develop into brain and spinal cord Nerves branch from this cord at regular intervals and connect to internal organs, muscles, and sense organs

Development of the Brain The brain is the control center of the nervous system where all electrical impulses originate and flow from. Intital development of brain starts with the brain stem and cerebellum Brain stem connects the brain to the spinal cord This part is the REPTILIAN BRAIN

Reptilian Brain Control’s body’s vital functions such as: Heart rate Breathing Body temperature Balance Reptilian brain is responsive and reliable but rigid and compulsive in its functioning This part of our brain is in SURVIVAL MODE

Mammalian Brain Responsible for emotions and feelings in our reality Records memories of behaviour as good or bad Involved in judgements that we make (often unconsciously) which exerts strong influence on our behaviour Parts of the brain involved: hippocampus, amygdala, hypothalamus

Neo-Mammalian Responsible for the development of human language, abstract thought, imagination, creativity, problem solving, consciousness Neo cortex is flexible and has almost infinite learning abilities Has allowed for human cultures to develop Evolution of the brain shows this part increases steadily in primates from the smallest monkeys to the great apes and humans. Part of the brain: cerebral cortex

These three parts of the brain work together. They have established numerous connections through which they influence one another When we are living in permanent state of fear or anger, or HIGH STRESS- our brain is in “struggle for survival” mode. Which part of our brain are we using when surviving?

CONSTANT STATE OF FIGHT OR FLIGHT We don’t need our ”reptilian” brain active ALL DAY LONG Behaviour patterns are: angry, aggressive, obsessive, compulsive, will do anything for sex Reptilian brain is used to manipulate us through marketing /politics Stress triggers reptilian brain: Thinking Unable brain shuts down to reason and process

Chronic stress/or trauma Two different patterns of responding emerge: Overarousal – hyper-vigilance (only looks like ADHD) Underarousal- shut down; numbe (only looks like depression)

What happens to your body systems when you are in a state of stress? What are some things you can do to regulate your stress?

Understanding the stress response ”Fight-or-flight" response because it evolved as a survival mechanism, enabling people and other mammals to react quickly to life-threatening situations. This careful process is helps mammals fight the threat off or flee to safety. Unfortunately, the body can also overreact to stressors that are not life-threatening, such as traffic jams, work pressure, and family difficulties. Chronic activation of this survival mechanism impairs health

THE NERVOUS SYSTEM The primary function of the nervous system is to coordinate and control the various body functions.

Nervous System The brain communicates with the rest of the body through the autonomic nervous system which controls involuntary body functions: Breathing Blood pressure Heartbeat Dilation or constriction of key blood vessels and small airways in the lungs called bronchioles

Rapid Heartbeat Sweating Dilated Pupils Energy. Your fight or flight system affects your glucose levels and uses adrenaline to provide your body with a flood of energy, which causes you to shake. Digestion/Bladder Issues - The fight or flight response slows digestion and weakens your bladder because these systems are not considered as important for your physical resources.

What are the health impacts of chronic stress? High blood pressures Promotes the formation of artery-clogging deposits Causes brain changes that may contribute to anxiety, depression, and addiction. More preliminary research suggests that chronic stress may also contribute to obesity, both through direct mechanisms (causing people to eat more) or indirectly (decreasing sleep and exercise)

Hyperventilation- The fight or flight response can cause you to breathe more quickly to adapt for the fight. This may result in hyperventilation, which is the cause of many other anxiety symptoms such as chest pains, light headedness, difficulty breathing, and more. Tingling/Cold Limbs- Severe anxiety can remove blood from some areas of the body (like the fingers and hands) and move that blood to the heart and other areas that need it. Difficulty Thinking- In the fight or flight response, overthinking can be dangerous. So the mind makes it harder to think to help you act more on instinct.

Techniques to counter chronic stress Relaxation response Physical activity Social support

Chordates Most Chordates are Vertebrates…but not all Invertebrate Chordates: (No backbone) Tunicates & lancelets Vertebrate Chordates (96% of all chordates) Fish Amphibians Reptiles Birds Mammals

Subphylum Urochordata Tunicates: Filter-feeding larval form has all of the chordate characteristics. adult tunicates, or sea squirts, have neither a notochord nor a tail.

Subphylum Cephalochordata Small, fishlike creatures called lancelets that live on the sandy ocean bottom. Adult lancelet has a definite head region that contains a mouth opens into a long pharynx with up to 100 pairs of gill slits water passes through the pharynx, a sticky mucus catches food particles. lancelet then swallows the mucus into the digestive tract Lancelets use the pharynx for gas exchange. Lancelet thin enough to exchange gases through their body surface. Closed circulatory system, but no true heart