• In this unit we will continue to discuss the characteristics of aquatic animals categorized as vertebrates (animals with backbones) and focus on birds and mammals.

• Summaries = Green• Underlined = Vocabulary

Aquatic Life – Birds & Mammals

http://www.westonfl.org/Images/CityImages/2008/images/aquatic_Bird.jpg

Review of Taxonomy

• Kingdom Animalia• Phylum Chordata

• Subphylum Vertebrata (animals that have backbones)• Superclass Tetropoda (organisms with four limbs)

• Class Aves (Birds)• Class Mammalia (Mammals)

What is a Bird?

• Birds, or Class Aves, are the only group of vertebrates, not including bats, with forelimbs modified into wings for flight.

• Birds, along with mammals, are endotherms and maintain an internal body temperature.

• Ornithology is the study of birds.

http://www.birminghamzoo.com/image_gallery/hi_res/peacock.jpg

Bird - Origins

• Birds evolved approximately 225 million years ago from feathered reptiles.

• Earliest known fossil is Archaeopteryx • considered first “bird”

because of presence of feathers; first fossil was found in 1861

• still had reptilian features such as clawed forelimbs, teeth and a long tail

• Video

http://www.damisela.com/zoo/photo/cq4/archaeopteryx.jpg

Bird - Respiration

• Avian respiratory systems contain extra air sacs, that are connected to lungs, extend throughout their bodies, allowing birds to take in large amounts of air.

• The ability to maintain extra oxygen in the system allows birds to supply their cells with more oxygen during flight and submersion.

Ron Freethy

Video

At Bodega Bay, California, wild pelicans dive into the sea to catch fish. This

one came back to the surface with at least three fish in his mouth. The

pelican was waving his beak to swallow the fish.

Photograph by Roger Lee

Bird - Circulation

• The avian circulatory system contains a 4-chambered heart and a double loop design.

• Oxygen-rich and oxygen-poor blood are separated from each other.

• Birds have a rapid heartbeat and high blood pressure to make circulation very efficient.

http://www.paulnoll.com/Oregon/Birds/Avian-

Circulatory.jpg

Bird - Reproduction

• Reproductive organs in birds are reduced in size except during nesting season.• Males have internal penis • Females only have one ovary instead of two.

• There are oviparous and lay external, hard shelled eggs.

• Internal fertilization, which occurs through cloaca.

• Bird eggs are similar to reptile eggs but have a larger yolk and they must be incubated and kept a constant temperature.

• Birds provide care for their young after they hatch.

http://www.uscg.mil/d5/msafety/rrt/images/eggs_noaa.jpg

Video

“Huddling together in subzero temperatures, these playful emperor penguin chicks face a

fight for survival in their Antarctic home with

temperatures plunging to -76F (-60C) and winds

over 100mph.” The Telegraph

Bird – Digestion & Excretion

• Birds swallow un-chewed food with a toothless beak and store it in the crop were it is later digested or regurgitated to feed their young.

• From crop, food moves to gizzard (muscular organ that usually contains small stones and breaks down food with help of digestive enzymes).

• Intestines absorb nutrients from food.

• Do not have a urinary bladder but excrete automatically.

• Some birds have salt-secreting gland to remove excess salt from bodies.

http://www.infovisual.info/02/img_en/055%20Internal%20anatomy%20of%20a%20bird.jpg

Class Aves

• Class Aves is classified into orders based on body structure and color, beak structure, foot structure, behavior, song, nest structure and placement or distinctive egg color and size. • Wading Birds (Waders) – Associated with coastal

areas and often seek sea life for food

• Diving Birds – Birds that plunge under water to dive for food

• Penguins – aquatic, flightless birds, live almost exclusively in the southern hemisphere

Migration

• Birds often travel long distances to reach warmer locations in winter (migration) to escape poor weather and seek a better food supply.

• They navigate in several ways using landmarks (rivers, mountains, coastlines), the Earth’s magnetic field, and the position of stars.

• Flocks of birds, or following neighbors, often fly together.

http://www.teara.govt.nz/NR/rdonlyres/47D2A3EE-0C5B-49CD-A86C-5B2689C86931/122295/hero7208.jpg

Bird – Adaptations for Flight

• Birds have feathers adapted for flight.

• Feathers are modified from reptilian scales (longer and fringed), made of keratin to insulate and protect the bird from weather.

• Feathers also provide smooth, low-friction surface.

• Oil from a gland at base of tail is used to smooth and waterproof feathers.

http://sophia.smith.edu/~jmoulton/Hawaii/images/animal%20parrot.jpg

Adaptations for Flight Cont.

• Bird skeletons consist of hollow bones (air reduces overall weight) and is very strong due to a network of cross braces within bone.

• Some bones are fused which reduces need for heavy ligaments.

CARLYN IVERSON / SCIENCE PHOTO LIBRARY

Adaptations for Flight Cont.

• The bird’s pectoral muscle (chest) is 25% of total weight and needed to flap wings during flight.

• Birds have a reduced body weight and are more compact to allow for flight.

Peter Theimann

What is a Mammal?

• A mammal is described as an organism that:• has hair or fur (made of keratin)• nourishes young with milk • and is endothermic and

maintains an internal body temperature.

• Mammals also have layers of fat that help them to keep warm and can have sweat glands to cool off.

• Mammals can be either aquatic or terrestrial for both; their forelimbs are adapted to a specific way of life (climbers, runners, diggers, flyers, swimmers).

http://www.ifwp.net/competition/compet_2006/450/ifwp2006_mammals3.jpg

Mammal - Respiration & Circulation

• All mammals, whether aquatic or terrestrial, breathe with lungs.

• They have efficient lungs, the sperm whale can stay submerged for up to an hour!

• Blowhole = fully aquatic mammals have an additional hole to breath in and out

• Mammals have a double-loop circulatory system with a 4-chambered heart.

http://training.seer.cancer.gov/module_anatomy/images/

illu_heart.jpg

http://www.well.com/user/pk/waterfront/photo-of-the-week/Blowhole.jpg

Video

Mammal - Reproduction

• Mammals are viviparous (live birth) and nutrients pass to the embryo from the mother through a placenta.

• Females have mammary glands to produce milk for their young.

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• Placental Mammals complete embryonic development in mother’s uterus.

Orders of Mammals

http://embryology.med.unsw.edu.au/

Notes/images/

placenta/plMembraneW600.jp

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Mammal – Feeding & Excretion

• The mammalian diet varies and, therefore, specialized teeth according to the diet.

• herbivores – eat plants

• carnivores – eat meat

• omnivores – eat both plants and meat

• blood-eaters – example would be vampire bat

• filter feeders – example is the blue whale with modified teeth called baleen for plankton

http://maxshouse.com/Teeth.jpg

“Made of keratin, like human fingernails

and hair, baleen plates on either

side of a whale’s enormous mouth

act as a huge strainer.”

From National Geographic

http://schools.look4.net.nz/science/biology/marine/fish/fish_files/baleen-whales.jpg

Mammal – Excretion

• Mammals have a complex digestive system using kidneys and intestines to excrete wastes.

http://marinemammalconservancy.org/wp-content/uploads/2010/03/anatomy.jpg

Mammal – Aquatic Groups

• Order Monotremata• Monotremes are different in that they lay eggs

(oviparous) but produce milk excreted from pores on the mother’s abdomen that the young lick milk.

• EX semi-aquatic duck-billed platypus

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• Carnivora – dogs, cats, bears

• Cetaceans – whales, dolphins, porpoises with thick layers of sub-cutaneous fat; are carnivores; cannot survive on land

• Sirenians – manatee, sea cow (aquatic herbivores)

Cont.

Sometimes called a sea cow, the placid manatee lives in shallow coastal waters and rivers. Photograph by Brian J. Skerry

• Pinnipedia – sea lions and walruses (Latin for pinna, “wing or fin” and ped-, “foot”)

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