1. Kounov, Pavel
Hristova, Aleksandra
10/4
Echinoderm
1. Echinoderm 2. Symmetry
Echinoderm is a phylum of marine The adults have radial symmetry.
animals. The larvae have bilateral symmetry.
In our everyday life we usually call them
“sea stars”.
There are 7000 living species now.
The name comes from Greek and in
means “spiny skin”
3. Anatomy
• Central disk- have nerve rings and
nerve cord on the arms
• Digestive glands- have digestive
juices that help storage of nutrients
• Radial canal- fluid containing, form
the water vascular system
• Madreporite- where the water flow in
or out
4. Ancestors and Place in the Cladogram
Kingdom: Animalia
Subkingdom: Eumetazoa
Superphylum: Deuterostomia
The classes are six :Crinoidea, Ophiuroidea, Asteroidea, Holothuroidea, Echinoidea, Concentricycloidea
The phylum is most close to the Birds (from the list)
All classes of Echinoderm came from Crinoidea
5. Characteristics
The water vascular system is the only derived characteristic of the Echinoderms. This is a network of
fluid canals that are called tube feet. They are used for gas exchange, feeding and locomotion.
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2. Another characteristic of the echinoderms is the decentralized nervous system. The system has
interconnected neurons with no central brain. Usually they have ganglion, which is a tissue of nerve
cells.
The interesting about the echinoderms’ skeleton is that it is composed of ossicles (tiny bones), calcium
carbonate, and several proteins.
6. Regeneration
An interesting fact about the echinoderms is that they are able to regenerate. This is a process in which
damaged or lost body parts re-grow. This is a very important process because sea stars discharge parts
when feeling danger. This process also leads to reproduction.
7. Reproduction
The Echinoderms are able to reproduce sexually and asexually. When mature the eggs and the sperm are
released in the water, so there is fertilization. Three species can reproduce internally(sea cucumbers, sea
stars, and brittle stars).
The asexual reproduction is possible only for the brittle stars and sea stars. When a sea star loses an arm,
it regenerates the arm and the arm regenerates the rest of the body, so the regeneration ends with two
echinoderms.
8. Avoiding Predation:
After many animals such as sharks and crabs eat echinoderms, they needed to do something in order to
save their lives. Some of them release toxins that are delivered by the tube feet, other- discharge sticky
entangling threats. All that may cause injuries when touching.
9. Feeding
The feeding is different for every specie. They usually eat shellfish, particles in the water and other sea
stars. When food particles touch the surface of the crinoids the tube feet push them to the mouth. Sea
cucumbers suck large amount of water and absorb the useful particles. Sea stars lock their arms around
the victim, release gastric juices and digest the animal alive.
10. Sea stars
They have multiple arms and moves
when the tube feet extend, grip and
release. The tube feet also catch clams
and oysters. The sea stars are able to
regenerate and reproduce that way. All
types of echinoderms live everywhere
around the world in the oceans.
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3. 11. Sand dollars
They have no arms. However they have
five rows of tube feet that are used for
locomotion.
They have the form of a flat disk. Sand
dollars catch small organisms with the
tube feet that they can swallow whole.
Their ecological role is to clean the sea
floor from food particles.
12. Feature star
The feature stars crawl using their
flexible arms. They feed by swallowing
big amounts of water and eat the useful
particles, which is also called suspension
eating.
13. Human Interaction
People know about the sea uchins because of the painful injuries they may get when touching them in
the sea. However, they are also used for making sushi. Every year more than 50 000 kg sea uchins and
sea cucumbers are captured in France, Peru, and Japan.
14. Fun Fact
Echinoderms have pigment cells and their beautiful colors are actually caused by the sun.
Vocabulary:
• Radial symmetry – The body parts of the animal are arranged around a central axis
• Bilateral symmetry – Those kind of symmetry have animals that have right and left sides (mirror
images)
• Water Vascular system – a network of hydraulic canals branching into extensions called tube feet
• Madreporite – the opening of a sea star’s water vascular system, where the water is pumped out
from
• Invertebrate – Animals that lack a back-bone (vertebrae)
• Ossicles – tiny bones
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4. • Central disk- have nerve rings and nerve cord on the arms
• Digestive glands- have digestive juices that help storage of nutrients
• Radial canal- fluid containing, form the water vascular system
• Ganglion - tissue of nerve cell bodies
• Regeneration - the process in which damaged or lost body part re-grow
Ivo, Lucho, Ira 10/4
Outline
Mollusca
1.History of the Mollusca:
• It is the second largest phylum of the animal kingdom
• They are one of the earliest form of life
• Starting 530 million years ago
(http://www.pearl-guide.com/pearl-producing-mollusks.shtml )
2. Name and Representatives:
• Mollusca is coming from the Latin word “mollis” which means soft (http://www.manandmollusc.net/ )
• Representatives are snails, octopus, squids, mussels, chitons, oysters and other
3. Characteristics
• They have soft body, with no cavity
• The body has double cell layers
• Bilaterally symmetrical (spherical symmetry)
• Has a heart and aorta
• Has a kidney
• Open circularity system
• Reproduction – sexual and unisexual
• Normally they have a “head” and a “foot” region
• They can live in the bottom of the ocean or in the top of the mountains
• They vary in size – from microscopic to giant
(http://www.ucmp.berkeley.edu/taxa/inverts/mollusca/mollusca.php )
4. Family
• Closer related are worms and echinodermata
• Humans are not very related because mollusca do not have vertebrae
(http://www.all-creatures.org/hope/gw/evolutionary_tree_002.gif )
5. Main Representatives of the Phylum
• Octopus
• Snails
• Mussels
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5. 6. Octopus
• Phylum mollusca
• Class cephalopoda
• Order-octopoda
• Octopuses are called “head footed because their tentacles are coming straight from the head, no body
• Interesting fact is that they have blue blood because of hemocyanin. The blood is pumped by 3 hearts, 2 for
oxygen-rich blood to the gills and 1 for the rest of the body
• Masters of camouflage-They have sacks with pigments called chromatophores. They are surrounded by
muscles which allow the octopus to control its color.
• Like their close, relatives the squids, octopuses release ink when they are in danger
• Octopuses may look lazy, but when they find themselves in danger they can boost up to 40 kph. They pump in
water and release it with their funnel with great speed
7. Snails
(http://www.snail-world.com/Life-Cycle-of-a-Snail.html)
• Snails live in various locations – deserts, cool climates, etc
• They eat plants, fruits, vegetables.
• They are considered to be hermaphrodites
8. Mussels
• Live in salt and fresh water
• Have a shell
• Marine mussels have filament that help them to attach to rocks they are called byssus
• They have a muscular foot that helps them dig
(http://en.wikipedia.org/wiki/Mussel )
9. Uses
• Food
• Medicine
10. Fun Facts
• Why did the shellfish go to the gym?
To get stronger mussels.
• "Why did the octopus cross the road?"
"To enslave and kill humanity!" (gallows humor)
(http://www.oum.ox.ac.uk/thezone/funstuff/jokes/fishjoke.htm )
• I take my new friend snail home with me and I get to the front of my house and he say, "That is a big
house. I wouldn't want to carry that on my back."
(http://www.emphasisallmine.com/emphasismine/2007/11/five-snail-joke.html )
VOCABULARY:
1. Mollis- soft ( Latin )
2. Shell- the outer protective membrane of animals, like snails and mussels
3. Muscular foot- in mussels, used for digging
4. Byssus - the things that help the mussel to attach to rocks
5. Chromatophores- sacs with pigments that are used for disguise
6. Hemocyanin- protein in octopus’ blood which makes the color of the blood blue
7. Mantle- highly muscled structure that houses the organs of the octopus
8. Radula - Tongue-like structure covered with tiny teeth which is coming out from the mouth
9. Slug - any of various terrestrial gastropods having an elongated slimy body and no external shell
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6. 10. Gastropod - a class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a
head bearing stalked eyes
Sponges & Cnidarians Delyan Karagerov
10/ 4 Iordan Milenkov
Radoslav Kokinov
1. Definitions:
Cnidarians are a group of aquatic animals that include hydras, corals, jellyfish and sea anemones. The cnidarian body
is very simple and consists of a sac with a digestive compartment, the gastrovascular cavity, which has a single
opening that serves as a mouth and anus at the same time. The body wall consist of a an epidermis (outer layer) and a
gastrodermis (inner layer). Movements are coordinated by a nerve net and since cnidarians lack a brain, sensory
structures, distributed around the body, help it detect and respond to stimuli from all directions.
Sponges are the simplest multi-cellular animals. They come in a variety of colors, shapes and structures. Sponges
don’t have internal organs and lack true tissues.
2. Symmetry:
Cnidarians are radially symmetrical.
Sponges have no deffinite shape, thus - asymmetrical.
3. Cnidarians: Characteristics
- Gastrovascular Cavity – Internal sack for digestion; it has only one opening (called “mouth”) through which
pass both food and waste; round the mouth there are tenticles
- 3 layers: Epidermis; Mesoglea; Gastrodermis;
- Epidermis: outer layer; includes cells that provide movement, cells that create eggs and sperm, and some
unique for the cnidarians cells (cnidocytes) ; nematocysts
4. Sponges: characteristics
- No organs or body systems (they are the simplest multicellular animals)
- The digestion of food happens in the cells only
- Don’t move (filter feeders)
- Can reproduce both sexually and asexually
- Their skeleton is composed of two parts: Sponging and Spicules
5. Possiton in the evolutionary tree and common ancestors
• Cnidaria is a phylum that belongs to the Animalia kingdom. Cnidarians were grouped with Ctenophores in
another phylum called Coelenterata, but the awareness of their differences in time set them as a separate
phyla.
• Nowdays, scientists think that cnidarians are very closely related to calcareous sponges.
• Sponges appeared about 600 mya and are the oldest animal phylum extant today
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7. • It is believed that the movement of all animals has started with cnidarians. They are the first animals that
possess a body with a definite form and shape (radial symmetry). They are ancestors to the first animals that
use together nerves and muscles.
6. How do sponges obtain food:
• Filter-feeders /very efficient with large inside volume;+ cells that have a sticky collar and flagella
/Choanocytes/ on the walls.The flagella force water in and out of the sponges’ inside volume, bringing in food
and oxygen and excreting waste. The food particles get caught by the collar cells and are transported within
the sponge by Amebocyte cells
7. How do Sponges Reproduce
Most of the Sponges are hermaphroditic, so thay have to obtain male and female roles which may switch next
time. The ‘male’ sponges releases sperm/gametes/ >> ‘female’ sponge fertilized internally >> larvae is
produced. The larvae floats in the water >> settles down and starts growing. Or by asexual reproduction:
internal/external budding or a piece of the sponge may break off
8. How do Sponges move:
Sponges don’t move. They settle in a place, start growing and are anchored/stuck to a rock or etc. Two types of
sponges: Encrusting sponges- cover rocks like moss does. And free-standing sponges- grow bid in size; large
inner volume; look like big funnels/chimneys
9. How do Cnidarians obtain food:
Most are carnivorous /eat crustaceans ,etc./ waste is excreted through the mouth. Food reaches all the cells through
Diffusion or by mesoglea cells.
Corals – filter water- absorb dissolved nutrients OR depend on endosymbiosis /e.g. algae/
Medusas – uses tentacles/+nematocyts/ + oral arms to catch the pray and paralyze it. Bring it to the mouth /gastro
vascular cavity/ where enzymes are secreted and break down the food. Flagella mix the enzymes and food until it’s
fully digested.
Sea anemones/hydras – Same but don’t catch - wait for pray to pass by.
10. How do Cnidarians Reproduce
Sexually: First a small larva is produced /planula/.It floats for sometime in the water than it settles to the seafloor
and develops into a polyp. It divides into a colony:– medusas are ‘shed off’ and mature – corals and sea anemones
stay as polyps. Asexually: By budding or splitting down the middle
11. How do Cnidarians Move
Corals- stay anchored to a spot without moving
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8. Medusas –swim freely or get dragged by currents or- ‘jet propulsion’: force water out their inside cavity by
contracting muscles
Hydras and sea anemones- mostly stay put and anchored but can detach and glide slowly using their tentacles / if
the conditions require it/
12. Representatives:
a) Hydra – Hydra Vulgaris (12mm)
- Live in most unpolluted sources of fresh water
- Food: They eat small aquatic invertebrates like Daphnia and Cyclops
- Life cycle: When conditions are good reproduce asexually (producing buds, that grow and break away from
its body); In winter – they reproduce sexually
b) Coral- Scleractina (aka Stone Corals)(1-3mm)
- Can be found in clear, shallow tropical waters; it is the main creator of the coral reefs
- Feed on many small organisms such as zooplankton and even some really small fish or vertebras.
- Just like all other corals, it doesn’t move.
- Reproduction – Sexual
c) Sponges - Gelliodes fibrosa(Gray encrusting sponge)(15mm-180mm)
- Live in shallow waters around the Hawaiian islands
- Food: filter water in order to obtain food; digestion is intracellular
- Reproduces both sexually and asexually
- Sessile animal (Don’t move; although some sponges move when they are really young)
13. What are human uses/interactions with Cnidarians:
Some jellyfish are eaten in orient cousin. Most cnidarians are harmless BUT some jellyfish and corals are
extremely toxic to humans- lethal: as “Sea wasp" Chironex fleckeri,which is also extremely hard to see. Also,
Coral riffs create the best beaches.
14. Fun fact
The Great Barrier reef is the biggest single structure made by living organisms. I fact it is the only living thing on
Earth that can be seen from outer space. It is 25 approximately 25 million years old and it is build by billions of coral
polyps.
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9. Fish
Naval life was most probably the first life on earth and the fish have been around for hundreds of millions of years.
Some of them were fierce predators, others fed on plankton. On thing is sure, that fish are one of the families that
have evolved and existed long before the first land animal. Fish are predecessors of mammals and some species are
closely related to reptiles. Fish and humans had a similar ancestor 408 to 360 million years ago during the Devonian
period.(1)
Fish are a very large part of the naval life and their multiple classes are all part of the Chordata phylum. Sharks, lung
fish or even the famous sprat are all part of the fish family but belong to different classes such as:
-Chondrichthyes- cartilage fish such as sharks
-Actinopterygii- ray- finned fish
Other classes such as the Dipnoi and Actinista have been extinct.(5)
Fish share similar, very specialized features that allow them to effectively live in the water such as gills, operculum,
swim bladder, and slimy scale skin so that they reduce the friction with the water.
Fish have uniquely adapted to swimming and respirating, as well as eating and reproducing under water.(3)
Reproduction: Fish are oviparous and reproduce by eggs which are discharged with thousands in the water and then
fertilized by male representatives.(3) Although large amounts of these eggs are eaten by other fish or birds, or even
humans, enough survive for the next generation to be born.()
Movement: Fish use the famous S-shaped movement to move around by alternatively contracting muscles on their
backbone.(3) The swim bladder prevents them from sinking or rising.(7)
Respiration: Although the oxygen in water isn’t much, fish are extremely efficient in respiration and not surprisingly,
have the largest and most dangerous predators in their family (fish grow big because of oxygen and food). Using gills
covered with a lid, fish extract oxygen directly into their bloodstream. The curved and folded gills provide a large
area for gas exchange and the oxygen only has to pass a small membrane (3 microns) to enter the bloodstream. Also
the water passes in only one direction. This is why fish extract 80% of the oxygen in the water whereas human only
25% of the oxygen in the air. (4)
REPRESENTATIVES:
There are many different kinds of fish adapted to different water environments but probably the most legendary
sweet water fish that has been known both for its strangeness, yuminess, and dangerousness is the catfish or сом.
Silurus Glanis lives in slow flowing rivers, dams, and lakes. Although usual catfish are no bigger than a foot or two,
there have been legends of extremely big catfish living in lakes around Bulgaria. In fact, the sight of a 2 meter Silurus
Glanis isn’t a rare one. The catfish is part of the Actinopterygii class and the Silurus genus. Its most distinctive feature
is the two mustache-like formations on both sides of its mouth. They are used to detect food and are called barbells.
9

10. Catfish are also bottom feeders because of their shrunk swim bladder and heavy structure. As a part of the ray-
finned fish, catfish have a strong leading spine ray, which when used as a defense mechanism can inflict severe
wounds.(2)
Although an interesting and mysterious fish, the catfish cannot rival the might of the Carcharodon Carcharias or
simply, the great white shark (class Chondrichthyes, Carcharodon genus) . This predator has existed for probably 25
million years and is the perfect naval predator since its process of evolution has ended during the time of its
ancestors. The shark is an active predator and uses few rows of serrated teeth to catch and tear apart its prey. The
biggest great whites have been known to reach 6 meters and weight 2-3 tons but this is a very rare phenomena. The
shark’s greatest weapon isn’t its might jaws that extend when it opens its mouth but its radar. Positioned on the
front of its head, where a nose would be the sharks have a complicated nerve system that responds to vibrations in
the water giving them the ability to see perfectly in water even without using their eyes. They simply need
something to move.(6)
Finally, after such spectacular fish, with a beer or two comes the fish of the year, the sprat. This small fish is part of
the Actinopterygii class and the Sprattus genus. It is a very small sea fish and isn’t special at all but it is a very famous
part of Bulgarian cruisine and is usually consumed with beer on the beach. Sprat feeds on plankton and lives in
shallow waters near shores.(9)
INTERACTION:
Human and fish have long interacted with each other. We have always seen fish as a food source and many cuisines
have fish as a whole part of their food culture (ex. Sushi). Big fish have occasionally fed on humans. These naval
creatures have long influenced many cultures and ancient mythological creatures. Nowadays, humans endanger
many fish species because of our constant oil spills and destruction of coral reefs. Whatever happens, fish have lived
long before our ancestors lived, they might just outlive us.(3)
Vocab: Bilateral symmetry- symmetrical along two perpendicular planes
Operculum-bony flap that protects their fins
Swim bladder- air sac that controls their buoyancy
Gills- structures that allow fish to breath under water
Active fish- fish that are feeding heavily and striking aggressively
Spiny Dorsal Fin- the upper, developed fin on the back of a fish (fin is the thin structure that fish use to move)
Olfactory nerve-part of nervous system of a fish, close the their nostrils
Oviparous- when the egg develops outside the mothers’ s body
Cartilaginous fish- Chondrichthyes (sharks, rays, chimaeras)
Marcheva, Sofia
Teneva, Nadya
10/4
Birds
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11. 1. What is the meaning of the scientific name?
• Aves (latin: birds)
• Class Aves belongs to Domain Eukarya, Kingdom Animalia and Phylum Chordata
2. Does this group have symmetry? What kind?
- Birds have Bilateral Symmetry
- Bilateral Symmetry is a symmetry around one plane; animals with bilateral symmetry have two
symmetrical parts (left and right), which are mirror images of each other.
2. How does this phylum fit into the evolutionary tree (cladogram)? Which other group (from your list) is most
closely related? How long ago did humans share a common ancestor with this group?
- Birds (Aves) are a class of Dinosauria. They have a Most Recent Common Ancestor with Reptiles – clade
Sauria 251 MYA; its early members were probably small lizard- like creatures.
- Their Most Recent Ancestor with Humans is probably around 350 MYA when the animals with amniotic
egg appeared.
3. Shared derived characteristics
- Feathers – used for flight; have variety of shapes and forms depending on their purpose
- Endothermic and four chambered heart – helps for a prolonged flight
- Large brains and expanded skulls
- Furcula (wishbone)
- Pneumatic skeleton – air sacs in bones, and bill
4. How do birds reproduce?
- Most male birds do not have external sex organs, but they do have testes, where sperm is produced.
Some such as the turkey have, but they are hidden inside the body until copulation. They are not used for
urination.
- Female birds have two ovaries, although only the left one functions
- During copulation, the female moves its tail to the side. The male moves the opening of his cloaca
to the female’s cloaca -cloacal kiss.
- The sperm is stored in the female’s cloaca from a week to a year depending on the species. Then eggs
produced by the female become fertilized by the male’s sperm.
- The eggs continue their development in the nest.
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12. 5. How do birds move?
http://www.biology-resources.com/images/bird-wing-structure-big.jpg
- Basically two types of flight – gliding flight and flapping flight
- Gliding – used by larger birds; flapping – used by smaller birds
- Many derived characteristics helping the bird to be lighter (already mentioned- furcula, pneumatic
skeleton)
- Wings – the most important characteristic; wings shaped like an aerofoil
- Because of its shape when air passes over the wing the pressure there becomes smaller (because the
same amount of air exerts pressure over bigger area), the opposite effect is experienced below the
wing.
- The shape and size of the wings changes depending on the habitat of the bird, and the flights that
they make (aspect ratio).
6. What type of nervous system is present in birds?
- Central nervous system – brain, spinal chord and nerves
- Nerves consist of neurons
- There are two types of neurons-sensory – triggered by sense organs and motor-transmit messages
from brain to muscles
- Autonomic nervous system – control essential action – heartbeat, breathing, and digestion.
- Very well developed areas for hearing and sight, but not so developed olfactory lobes
-
7. Indian Peafowl (Pavo cristatus)
• range: from eastern Pakistan to India and then south from the Himalayas to Sri Lanka
• domesticated 2000 years ago and exported to many countries due to its beauty
• female bird – peahen, male bird – peacock
• Peafowls and pheasants - family Phasianidae
• Blue Peafowl and Green Peafowl (lives in Southeast Asia) can interbreed although their natural habitat
ranges do not cross
• natural habitat: dry open forest; tropical forest; riparian areas
• don’t fly long distances
• eat young cobras (valued by Indians), insects, small reptiles, seeds, plant seedlings and fruit
• drawn to gardens, where they cause problems
• peahens are more attracted to peacocks with more spots on their feathers
• Males - specific courtship dance; whoever dances the best wins the attention of the females
• Attractive peacocks make harems with no more than 5 peahens
• Nest - 3 to 5 brown eggs that hatch in 1 month
• Females incubate the eggs and take care of the children (peachicks)
• Small peafowls are able to feed from birth and reach maturity at 2-3 years of age
• Very adaptive bird (adapts to cooler climate)
8. American Flamingo (Phoenicopterus ruber)
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13. • Distribution: coastal areas of the Caribbean incl. the Bahamas, Cuba, and the Yucatan peninsula; also
southern United States, the Middle East, Africa, and northern South America
• Habitat: Saline lakes, coastal lagoons and other shallow salt water territories
• Food: Crustaceans, mollusks, insects, algae and diatoms with carotenoid pigments
• Live in large flocks
• Group migration to breeding cites
• Filter feeding: their long neck allows them to put their bill into the water and collect both water and food;
then their tongue pushes out the water and only the food is left in the bill
• Monogamous
• Build a nest which must be high enough to keep the eggs and the chicks above floodwaters and to protect
them from predators
• Both the male and the female flamingo incubate the egg, which hatches in 27-31 days
• Reach maturity at 3-6 years of age
• Live about 50 years
• Resting: stand on one leg with their head under their wing – preserves body temperature
• Large population decline caused by a habitat loss and hunting
9. Ostrich (Struthio camelus)
• Flightless bird, largest living bird in the whole world
• Eat: shoots, leaves, flowers, seeds; can go without drinking
water several days
• Habitat: flat areas in Africa where the rainfall is less
• Ostriches live about 40 years
• During the dry season, they nest; the female lays no more than
12 eggs for 6 weeks
• Only 15% of chicks live more than 1 year because of the many
predators, such as the hyena and the jackal
• Great vision and strong legs that enable them to run at 31
miles per hour 10
• Ostriches are farmed all over the world
• Its feathers are used for feather dusters and its skin for
leather
• Meat - sold around the world
• In some African countries people race on the backs of ostriches
10. Interaction between Humans and Birds
• Some birds – agricultural pests
• Human activities cause extinction of birds
• Birds transmit diseases, some of which can infect humans
• Poultry – biggest source of animal protein for humans
• Hunting for obtaining meat or feathers
• Guano – source of Phosphorus and Nitrogen
• Pets
• Messenger pigeons – used till WWII
• Sports – pigeon racing
Vocabulary Words
1. Amniotic Egg - egg produced by birds, reptiles, and egg-laying mammals; the embryo develops inside a
membrane that is either calcium based or leathery.
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14. 2. Endotherm – warm-blood
3. Furcula (wishbone)- bone by the fusion of the two clavicles; strengthens the skeleton; helps flight
4. Copulation – act of sexual intercourse
5. Cloaca - posterior opening that serves as the only such opening for the intestinal, reproductive, and urinary
tracts of certain animal species
6. Neurons- cells that transmit micro-electrical pulse
7. Bill- The horny part of the jaws of a bird; a beak
8. Guano – seabird feces
9. Poultry – domesticated birds for meat and eggs
10. tail coverts - feathers that cover the base of the tail feathers
11. trains – peafowl’s beautiful feathers on its tail
12. saline – salty
13. riparian – coastal
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15. MAMMALS
1. What is the meaning of the scientific name for this clade(s)?
• From Late Latin: mammalis, meaning “of the breast”
• Term in Bulgarian: “БОЗАЙНИЦИ”
2. Does this group have symmetry? If so, what kind?
Mammals tend to have bilateral symmetry. This means that these species have two symmetric sides - a left and a
right half. They also have a dorsal, which means the top of the mammal, side, ventral(bottom), anterior(front) and
posterior(back) side. Mammals tend to have their nervous system concentrated to their anterior end such as the
brain(“CR”).
3. How does this phylum fit into the evolutionary tree (cladogram)? Which other group (from your list) is most
closely related? How long ago did humans share a common ancestor with this group?
• They appeared on the Earth relatively recent, compared to other organisms – 265 MYA
• They are most closely related to Reptiles, because are the two parts in which the group “Amniotic egg” is
divided.
• Humans are part of this group. Humans are mammals, but the human as we know it nowadays (the first known
example is Homo habilis) appeared 2,5 million years ago.
4. Explain derived characteristics that are unique to that clade. What distinguishes these organisms from other
groups?
• Mammary glands – function in producing milk for nourishing the offspring, since milk is a substance rich in fats,
sugars, proteins, minerals, and vitamins; serve as the primary source of nourish for young mammals, and they
are can obtain nutrition in this way even before they are physically able to digest other type of food
• Hair – composed of the protein keratin; functions in: insulation (heat regulation, since mammals are warm-
blooded); protection (in addition to the skin); camouflage (protective coloration, which allows some mammals to
blend into their environment in order to avoid being seen by predators, which may attack them, or prey, which
they are going to attack so that they obtain food); sensory function (detects information from senses; for
example, a cat can use its whiskers to sense the presence of nearby objects even withouth seeing or touching
them)
• Three middle ear bones – consists of three bones: malleus, incus, and stapes (in early reptiles, malleus and incus
were bones from the jaw but evolution occurred; today reptiles’ the stape still comprises the ear); function in
transmitting sound vibrations and allowing animals to hear
• Differentiated teeth (Heterodont teeth) – vary in size and shape; adapted for chewing many kinds of foods;
mammals’ teeth are specialized; e.g. for cutting and shearing – incisors (резци) and canine teeth (кучешки
зъби); for grinding and crushing – premolars (предкътници) and molars (кътници)
5. How do they reproduce?
The first mammals, the monotremes used to lay eggs. Once the offspring got out of the egg, were fed on milk.
Nowadays, most of the mammals in the world are placental mammals. This means that the embryo that develops
inside the mother-carrier, is connected to the mother’s blood supply, allowing it to receive nutrients and to
eliminate waste(“Placenta”). This allows the fetus to grow in size considerably. On the other hand, in all other
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16. vertebrates, the embryo is separated by the mother and the egg is developing on its own and thereafter no nutrients
can enter the egg. So the only nutrients that the egg can use are the initial ones. This leads to extremely small in size
offspring. Placental mammals are born more developed than non-placental mammals. This is so because with the
presence of the placenta, the embryo can stay longer inside the mother-carrier receiving nutrients and sending away
waste through the mother. This allows the embryo to grow larger, which makes this type of animals more successful.
Once the baby is born, usually one of the parents takes care of it, until it is ready to take care of itself. The
fertilization of the egg takes place high in the fallopian tubes(leading from the ovaries to the uterus(where the baby
develops)). In these tubes, the first cell division starts as it goes down to the uterus. This eggs transforms into a ball
like structure that is separated into an outer layer of cells and inner cell mass. The outer layer is called chorion and
the inner cell mass- zygote. Once the egg had reached the uterus, the placenta grows from complex materials. There
are more than 5 different forms of placenta in the different species of mammals. They differ in the thickness of the
placenta and other factors(“Reproduction”).
6. How are gases, food/wastes exchanged with the environment (respiration/circulation)?
Mammals can not live without oxygen, because it is needed for metabolism in their cells.
In the process of breathing, they inhale oxygen from the air with their lungs, and then exhale carbon dioxide. As of
plants, they use the exhaled carbon dioxide in order to photosynthesize, and then they release oxygen. That is how
an exchange of gases happens between mammals and the environment.
Waste includes: byproducts of digestion, which are discarded by the body. In the environment, these byproducts are
decomposed by microorganisms and nutrients are released in the soil. These nutrients are needed by plants.
7. How does the organism maintain control (nervous system)?
Mammals have the most complex nervous system; consists of the central nervous system (CNS – includes the brain
and the spinal cord) and the peripheral nervous system (PNS – nerves and ganglia, clusters of nerve cells); nervous
tissue is made up of two main types of cells: neurons (carry impulses around the body) & neuroglia (also known as
glial cells; maintain proper biochemical levels for the neurons)
Functions:
- sense and responses to stimuli
- responsible for generation of information (thoughts, emotions, forming and storing memories)
- PNS: collecting sensory stimuli and transporting it to CNS; transporting messages that control the body’s
response
- CNS: generating information
- neocortex – only mammals possess it; functions in sensory perception, generation of motor commands,
spatial reasoning, conscious thought, and language
8. Representative organisms.
http://www.aronsha.com/PhotoDetail-new.cfm?image=GJB00X05-Ring-tailed- Lemer.jpg&cat=wildlife
Ring-tailed lemur (Lemur catta):
• Habitat: deciduous forests (made up of trees that lose their leaves every year), dry
scrub, highland humid forests, and gallery forests, which are forests along
riverbanks; in general, the ring-tailed lemur inhabits dry woodland districts that have
a seven to eight month dry season
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17. • Range: found only on southern and southwestern Madagascar, an east African island
• What they eat: they are classified as herbivores; they eat mostly leaves (especially leaves of tamarind tree), fruits
(berries), and flowers; however, from time to time, lemurs eat bird eggs, insects, and small mammals; as a
source of water, they lick dew from leaves
• Locomotion: the lemur moves quadrupedally (on its four limbs); walks or runs on the ground as well as on the
tops of branches; its tail stands up for balance
• Ecological role/ niche: significant ecological role in Madagascar; make an extensive use of the ground; have the
ability to adapt to different environments; range further than any other lemur species into the interior of
Madagascar; threatened with extinction because of deforestation, etc.
• Life cycle changes: weaning (stop feeding offspring with mother’s milk) takes about 6 months; childhood - for the
first weeks, young are carried in their mothers’ mouths or on their mothers’ belly, then they start riding on their
mothers’ backs; reach sexual maturity at about 15 months (1 year & 3 months); gestation period (pregnancy)
lasts for 132-134 days (about 4.5 months); give birth to 1 or 2 babies; birth season – late summer/early fall; life
span – up to 27 years (in captivity, not in the wild)
• Other characteristics: grooming claw – used for personal grooming of the fur; opposable thumb; enjoy
sunbathing in the morning before feeding: “worshipping the sun” in Lotus position (Yoga)
Koala(Phascolarctos cinereus): http://www.stanford.edu/~jay/koalas/Koala450j.jpg
• Habitat: In the quite few eucalyptus forests of Eastern Australia. Very typical for
these forests are the large variation in geology, climate, land form of vegetation.
So in general koalas like the eucalypt forests because of their diversity of
species and the presence of eucalypt itself which is a major food source for
them(“Parks”).
• Range: From northern Queensland to southern Australia(“Habitat”).
• Food: What do the eat? They live almost only on eucalypt leaves. Koalas have
adapted to the surrounding environment, since the eucalypt leaves are extremely
low in protein and contain substances that are poisonous to most other animals.
In the different environments, koalas prefer different types of eucalypt such
as: Tasmanian blue gum (Eucalyptus globulus - pictured), Gippsland manna gum (Eucalyptus pryoriana), manna
gum (Eucalyptus viminalis), and swamp gum (Eucalyptus ovata) (“Friends”). Also there have been some koalas
observed eating tea tree, wattle(плет), and some pines. Koalas rarely drink water, they consume their necessary
dose by rain drops on the surface of the leaves and from the leaves themselves.
• Locomotion: Koalas have a very low metabolic rate and therefore they spend 16 to 18 hours a day motionless.
Most of it they spend sleeping. They walk by both their hands and legs. They have powerful claws that help them
climb trees and fight other koalas for food.
• Life cycle: Female koalas reach maturity at age of 2-3 years. Their gestation is 35 days. A baby koala is hairless,
blind and earless. It is only an inch long when new born. The offspring remain hidden in the mother’s pouch for
six months where they feed on milk. They grow in size and develop organs during this time. When the baby gets
out of the pouch, it will stay with the mother, riding on her back for another six months and eating both eucalypt
leaves and mother’s milk.
• Human interactions: Very cute animal but gets easily irritated
Leopard (Panthera pardus):
http://www.cites.org/gallery/species/mammal/leopard2.html
• Habitat: grasslands, woodlands and riverside forests; animals
have been studied in open savannah habitats; generally
considered nocturnal animals (e.g. being active during the
night); they can also be diurnal and crepuscular, as rainforest
leopards are; they are exceptionally adaptable
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18. • Range: found mostly in central Africa, can be also found in south Asia (India/ South China).; they are missing in
North and South America.
• What they eat: classified as carnivores; they are stalkers, they wait hidden somewhere, and then suddenly attack
and kill very fast; most likely to hunt between sunset and sunrise; their diet includes: ungulates and monkeys,
but also reptiles, bird, and fish; in Africa, leopard’s most commonly killed prey are the antelopes, especially
impalas
• Locomotion: they move quadrupedally, run very fast, and have the ability to climb trees even with a prey in its
jaws.
• Ecological role/ niche: they must compete with other animals for food and place to live; larger predators like
tigers and lions can take their prey or kill its infants; so it is better to hunt in different arias from them, which
means it uses different animals as its food.
• Life cycle changes: they can mate all year round; the estrous cycle lasts 46 days and the female usually is in heat
for 7 days; gestation - 100 days; the little leopards are in a litter of 2-4, but only 1-2 are able to survive their first
year (big infant mortality); the female will search for a hidden, quiet place, because it needs to take care of the
cubs in the beginning; they open their eyes 10 days after they are born, but they stay with their mother from
18-24 months, before leaving them and start hunting and living only by themselves.
• Other characteristics: stealth predators; the only known big cat that can take its pray up to a three, and
sometimes the prey is times heavier than; variant of coloration:
• Red/orange in the savannah;
• Pale cream and yellow brown in the desert;
• Golden in the rainforest;
• Melanistic (black) in the high mountains.
9. What are human uses/interactions with organisms in this group? (We eat them, they make us sick, etc.)
Humans are actually mammals. However, various human-mammal interactions exist, including the following:
• We eat other mammals…but sometimes they eat us
• We obtain food produced from mammals (e.g. milk from cows)
• We make clothes of mammals’ fur, etc.
10. Fun fact & trivia.
Do you know…
To which animal group most of the characters in The Lion King belong?
– Mammals, of course. Simba is a lion; Timon is a meerkat; Pumbaa is a warthog; Rafiki is a mandrill…the list is
REALLY long
Fun Facts about Mammals:
• Male lions prefer to rest while females are doing most of the hunting.
• Just like humans, dogs and cats can be either right or left-handed (or should we say ‘pawed’)
• A ring-tailed lemur’s tail is longer than its body
Glossary:
1. Occipital condyles – undersurface facets of the occipital bone in vertebrates
2. Synapsids – group of amniotes, to which mammals belong
3. Monotremes – like all mammals, monotremes have hair and produce milk, but they lack nipples
4. Marsupials – Opossums, kangaroos, and koalas
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19. 5. Placenta – structure in which nutrients diffuse into the embryo from the mother’s blood
6. Opposable thumb – a thumb which makes primates different from other animals, they can touch the ventral
surface of the tip of all four fingers with the ventral surface of the thumb of the same hand
7. Neocortex – brain region that is unique to mammals.
8. Bronchus – is a passage of airway in the respiratory tract that conducts air into the lungs
9. Alveolus – an anatomical structure that has the form of a hollow cavity in lungs
10. Warm-blooded – maintaining a nearly constant body temperature, usually higher than and independent of
the environment
11. Malleus, incus, and stapes – the three bones that comprise the middle ear of mammals
12. Fetus – developing mammal after the embryonic stage and before birth
13. Uterus – a female reproductive organ, within which the fetus develops during gestation
14. Wean – to stop feeding offspring with mother’s milk
15. Gestation – the process of carrying offspring in the womb during pregnancy
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