1. Kiril Krendov
Siyana Petrova
Teodora Zdravkova
10/2
Fish
A Biodiversity Project
1. Scientific name
“Ichthyoid” – fish-like or hagfish and lampreys, similar to fish but not true fish
Ichthyology = from the Greek ἰχθυ, (ikhthu, fish) and λόγος (logos, reason), the scientific study of fish,
particularly in taxonomy, zoogeography, anatomy, systematics, and ecology. (15)
• Can be cartilaginous (sharks, rays) or bony (other). Hagfish are most primitive.
Derived Characteristics:
- Their skin is covered with scales.
- Their limbs have modified into fins.
- They have gills, instead of lungs.
- Heart is two-chambered
- * Bilateral symmetry
2. Cladogram
a. Evolution: Closely related are the Amphibians.
Domain: Eukarya; Kingdom: Animalia; Phylum: Chordata
b. Human/Fish Ancestor
The common ancestor of humans and fish probably is believed to contain only 12
chromosomes. By studying the genomes of fish and mammals, scientists were able to
determine that it lived in the Paleozoic era (about 450 million years ago). The ray-finned
fishes, which are the majority of fish known today, duplicated their genome shortly after the
separation of the t lineages of mammals and fish. (14)
3. Reproduction
- Ovoparity-- lay undeveloped eggs, external fertilization (90% of bony fish) or
internal fertilization (some sharks and rays)
- Ovoviviparity- internal development (without direct maternal nourishment)
-advanced at birth (most sharks + rays) or larval birth (some scorpeaniforms-rockfish)
- Viviparity - internal development (direct nourishment from mother) fully
advanced at birth
4. Gas, Food/Waste Exchange with Environment
a. Respiration
A large number of fish exchange gases due to the gills positioned in either side of the pharynx
( the head). In the gills, which provide a large surface area for exchanging oxygen and carbon dioxide,
the process of respiration occurs. Through the gills, the blood picks up oxygen from the surrounding
water and distributes it through arteries that lead to all parts of the body. When the oxygen is used in
the body, it goes back to the heart and this path represents a relatively simple closed-circle circulatory
system. (12)
b. Food/Waste Exchange
Jaws allow fish to eat a wide variety of food, including plants and other organisms. The food is
being ingested through the mouth and broken down by digestive enzymes( which catalyze reactions),
then the available nutrients are absorbed. Organs such as the fish liver or the pancreas add digestive
enzymes to the food that travels through the digestive tract. After digestion, the process of excretion
logically follows. Most fish release their food wastes as ammonia. Some of the wastes are diffused
through the gills, blood wastes are filtered by the kidneys. (12)

2. 5. Movement
Even thought the density of water is higher than that of air, fish still can move quickly
and smoothly. The skeleton of fish is one of the most complicated ones; it provides
framework for the movement. The muscles, which are 80% of the body, provide power. The
vertebral column acts as levers that operates the movement.
- The streamlined shape of the fish and a special slime fish excrete from their skin
minimizes the drag.
6. Fish Thermal Strategies
In general, fish are cold blooded. They derive their body heat from their environment and conform
its temperature. As water has a high heat capacity, it is able to easily suck any excess heat out of a fish
and into the environment.
a. Ectothermic: fish derive their heat from the environment
Endothermic- ‘‘within- heating’’
b. Poikilothermic: fish conform to the heat in the environment
Some large, fast-swimming fish are not ectothermic. For instance, the tunas and mackerel
sharks can actually have core body temperatures ten to twenty degrees Celsius higher that the
surrounding water. They are endothermic and derive their body heat from their metabolism, but they
are still ploikiothermic; their body temperature may be higher than the surrounding water, but they still
conform to the temperature of the water, just 10-20 degrees above it. (12)
Why should they bother having an elevated body temperature?
To increase the speed of the fish. The higher the body temperature, the greater the muscular power.
Thirty degrees Celsius is the optimum temperature for muscular speed.
7. Class Chondrichthyes (Cartilaginous Fish)
Common Name: Whale Shark
Latin Name: Rhincodon typus
*The largest fish on earth (mouth = 1m- 1.5m, average lengh = 7-8m, biggest = 12-14m, weigth =
15-20 tones) (1,2,3).
Food: Even though the whale shark is the largest fish on Earth, they are known to be filter
feeders(2).It eats by sucking water with all the small animals in it such as: krills, crabs, planktons,
squids(1,2).
Habitat: Whale sharks live in warm seas
such as the tropical parts of the Atlantic,
Indian and the Pacific ocean (1,3) because these
oceans' water temperature on the surface
ranges between 20 and 27 0C (4) .
Reproduction: Whale sharks are viviparous
meaning they give birth to their offspring (3).
They give birth to around 300 small sharks at
the same time, each ranging from 0.55 to 0.6
m long (3,4) .
Life Cycle: Whale Sharks migrate following
its food (seasonal feeding). Usually their life is long as much as 100 years (3).
Locomotion: Known as slow swimmers, whale sharks move their whole body in order to move
through the water (in contrast, most sharks and fish move only their tails) (3).
Ecology: Human impact: whale sharks are easy to catch by fishermen because they swim at the
surface of the water (4) . A highly valued product in Taiwan and China (4)!
8. Class Osteichthyes (Bony Fish)
Common Name: Clown Fish
Latin Name: Amphiprion percula

3. * Unlike the whale shark, the clown fish is a very small animal with length ranging from 5 to 13
cm(6).
Habitat: lives near anemone which is a poisonous plant that lives at the sea bottom and eats fish (6)
. When another fish touches it, the plant omits its poison and kills the fish (6). Also they live in the
parts of the Indian and Pacific Ocean (7).
Food: Its source of food, as well as protection, is the anemone. The clown fish eats dead anemone,
parts of poisoned fish that the anemone does not eat and plankton (6).
Reproduction: Again the anemone plant is used for protection during the period of reproduction.
The male clown fish builds a nest near it which is the place where the numerous eggs are
put(between 100 and 1000) (7) . The eggs turn into small fish after about 4 to 5 days (7) . Clown fish
are known to be hermaphrodites (7).
Locomotion: Clown Fish move via fins. With them they change speed and direction. The clown
fish has 4 types of fins - dorsal and ventral (both used for balance), caudal (used to improve
forward movements), pectoral (used to navigate and change direction) fins (8).
Ecology: Clown fish are not threatened by human activity. It has a close relationship with
anemone plants.
9. Class Agnatha (only two living species now- Fagfish and Lamprey)
Common Name: Hagfish (YES IT IS A FISH)
Latin Name: Myxine glutinosa
* Most primitive fish! It is between 0.4 and 0.6 m long (10). A jawless fish with cartilage skeleton.
Habitat: It lives in depths between 20 and 600 m(10). They prefer muddy sea bottoms(10).
They live primarily in the Atlantic Ocean near the coasts of America and Europe.
Food: They eat dead fish which drop on the bottom of the sea and worms(10).
Reproduction: Hagfish are able to reproduce only after they reach 25 to 28 cm (10). They have
both sexual organs, however, only one them (either the male or female) is fully developed (9) .
They reproduce by eggs- ranging from 19 to 30 for each reproduction (9).
Locomotion: Hagfish have no fins. They move by tails that resemble the sculls of a boat.
Ecology: Hagfish represent no treat for humans. Most hagfish are disgusting and that is why they
are not eaten. Yet there is one species kkomjangeo which is eaten in Korea (11).
10. Human- Fish Interactions
Fish is an important human and animal food source, which is ‘hunted’ in wild fisheries or in
‘farms’. They are also caught and raised by fish keepers and scientists, then exhibited in public
aquaria. Furthermore, fish have had an interesting culture role through the ages, serving as deities,
religious symbols, subjects of art and books. For instance, fish has religious significance in Hindu,
Jain, Buddhist, and Christian traditions (referring to feeding the multitude in the desert).
11. Fun facts
• If you keep a goldfish in a dark room, it will eventually turn white.
• A shark can detect one part of blood in 100 million parts of water.
• The most poisonous fish in the world is the Stone fish.
• The largest known fish in the sea is the Whale Shark. It weighs up to 20 tons and grows to a
length of 40 feet.
• In Texas it is illegal to have sex with a fish, in Florida it is illegal to get a fish drunk. (13)

4. Vocabulary List:
1. Finns – modified limbs, used for movement
2. Gills – the things with which fish breathe, instead of with lungs
3. Ectothermic – fish derive their heat from the environment
4. Poikilothermic – fish conform to the heat of the environment
5. Ichthyology – study of fish
6. Viviparous – giving birth to their offspring
7. Anemone – poisonous plant that lives at the sea bottom and eats fish, clown fish lives
near it
8. Bony fish – found in lakes, rivers, seas (Lungfish, Trout, Bass, Salmon, Perch, Parrot
Fish)
9. Cartilaginous fish – large marine animals (sharks)
10. School – group of fish
Work Cited:
1. Klappenbach, Laura. "Whale Shark - Rhincodon typus." About.com. About.com, a part of The New York
Times Company., n.d. Web. 21 Mar 2010. <http://animals.about.com/od/cartilaginousfishes/p/whaleshark.htm>.
2. "Whale shark." Wikipedia, the free encyclopedia. Wikimedia Foundation, Inc., 23 March 2010 . Web. 24 Mar
2010. <http://en.wikipedia.org/wiki/Whale_shark>.
3. "WHALE SHARK." Enchanted Learning.com. EnchantedLearning.com , 2009. Web. 25 Mar 2010.
<http://www.enchantedlearning.com/subjects/sharks/species/Whaleshark.shtml>.
4. Gaut, Alex. "The Whale Shark." Marine Education Society of Australasia. MESA, n.d. Web. 21 Mar 2010.
<http://www.mesa.edu.au/seaweek2005/pdf/infosheet05.pdf>.
5. "Whale Shark Question and Answer." Shark Research Institute. Shark Research Institute, n.d. Web. 25 Mar
2010. <http://www.sharks.org/whale_shark/whalesharks_questions.htm#SIXTEEN>.
6. Same Source like #3 http://www.enchantedlearning.com/subjects/fish/printouts/Clownfishprintout.shtml
7. "An Exploration of the Clownfish." Tree of Life Web Project. Havergal College, 2005. Web. 21 Mar 2010.
<http://tolweb.org/treehouses/?treehouse_id=3390>.
8. Same Source like #2 http://en.wikipedia.org/wiki/Fish_anatomy
9. "Hagfish." Hagfish. Gulf of Main Research Institute, Gulf of Main Research Institute. Web. 21 Mar 2010.
<http://www.gma.org/fogm/myxine_glutinosa.htm>.
10. "Hagfish." Science Encyclopedia. Net Industries and its Licensors , 2010. Web. 21 Mar 2010.
<http://science.jrank.org/pages/3185/Hagfish.html>.
11. Same source like #2 dhttp://en.wikipedia.org/wiki/Hagfish
12. Buchheim, Jason. "FISH, a Quick Course on Ichthyology." Odyssey Expeditions - Tropical Marine Biology
Voyages! Web. 25 Mar. 2010. <http://www.marinebiology.org/fish.htm#How%20Fish%20Breath>.
13. "Useless Fish Trivia and Fun Facts about Fish." Comedy Zone for Jokes, Funny Pictures, Cartoons and Stand
Up Comedians. Web. 25 Mar. 2010. <http://comedy-zone.net/triviazone/animals/page6.htm>.
14. "Our Fish Ancestors." Site Du Genoscope. Web. 25 Mar. 2010.
<http://www.cns.fr/externe/English/Actualites/Presse/201004_1.html>.

5. 15. "Dictionary of Ichthyology." Brian W. Coad - Personal Website. Web. 25 Mar. 2010.
<http://www.briancoad.com/Dictionary/I.htm>