The Diversity of

Life

AMPHIBIANS• EVOLEVED FROM LOBE-FINNED

FISHES

• 3 ORDERS

• URODELA (with tail) - Salamanders

• ANURA (without tails) - Frogs/toads

• APODA (without feet) – look like snakes – (Rare – not many examples)

Amphibian Characteristics

• Most undergo metamorphosis (going from aquatic larval stage to terrestrial adult stage)

• No scales

• Combination of gills, lungs, skin breathing

• Most have external fertilization

• Eggs without shell

CLASS REPTILIA

• Dominated the earth from 300 million to 65 million years ago (the Mesozoic era)

• Dinosaur extinction: Asteroid-impact hypothesis

• Major characteristics: Amniotic Egg, watertight skin, exothermic

Reptile Orders• Chelonia: Turtles

• Crocodilia: Crocodiles and alligators

• Squamata: Lizards and snakes

Rattlesnake

Reptile Interesting Facts• Autotomy: ability of some snakes to

detach tail, which continues to move, in order to distract predators

• Pythons and Boa Constrictors have small nubs that are believed to be vestigial legs

• Snakes can swallow objects larger than their head because they have a flexible skull

CLASS AVES

CHARACTERISTICS• FEATHERS• WINGS• RIGID FLIGHT SKELETON• AIR SACS• ENDOTHERMIC (104-106F)• BEAK / NO TEETH• OVIPARITY (Lay amniotic eggs)

ARCHAEOPTERYX

Wing Development• Tree Hypothesis: Flight began with

organisms jumping from trees and gliding

• Net Hypothesis: Wings initially served as nets for capturing insects

• Heat hypothesis: feathers developed as an adaptation in heat regulation

DIGESTIVE SYSTEM

• CROP – enlarged part of esophagus, moistens food

• GIZZARD – Second part of the stomach which crushes food with help of stones the bird intentionally swallows.

ORNITHOLOGISTS

Biologists who study birds

Interesting Bird Facts

• The largest bird is the Ostrich (9 feet tall and weigh over 300 pounds)

• If an average man had a metabolism comparable to that of a hummingbird he would have to eat 285 pounds of hamburger every day to maintain his weight. Hummingbirds can fly backwards

• The bones of a pigeon weigh less than its feathers.

• In 1998, USA hens produced 6.657 billion dozen. The average chicken lays approximately 260 eggs per year

• 10,000 species of birds divided into 29 orders

• New York City has the largest population of peregrine falcons in the world.

• The nest of a bald eagle can be 12 feet deep,10 feet wide and weigh over a ton.

• Although domestic turkeys can not fly, wild ones can fly up to 55 miles an hour but only for short distances

CLASS MAMMALIA• 4,400 DIFFERENT SPECIES

• 20 ORDERS

Characteristics

• Endothermic

• Mammary glands

• 4 chambered heart

• Hair

• Specialized teeth

Endothermy• Regulate own body temperature

• In humans = 98.6F = 37C

• Opposite of exothermic

• Endo= inside / exo = outside

• In past called warm-blooded / cold-blooded

Specialized Teeth• Incisors: Chisel-like, used for

cutting

• Canines: Pointed, used to puncture/tear

• Molars: Flat, used for crushing

Four Chambered Heart

• More efficient• SEPTUM: Wall

that separates left and right side of heart

Mammalian Orders• Monotremata: Lay eggs, only 3 living

examples which includes Platypus and Echidna Anteater

• Marsupials: live birth but young not fully developed; Opossum, Kangaroo

• Rodentia: Largest mammal order (40% of all mammal species)

• Chiroptera: Bats

Platypus

Kangaroo

Class Rodentia• Mice, rats, squirrels, chipmunks, hamsters,

beaver, porcupines, gerbils, etc…

CHIROPTERA

Over 1,000

different

species of

bats

• Carnivora: Dogs, cats, lions, tigers, bears, etc…

• Primates: 235 living species, which includes Homo sapien

• Artiodactyla: Mammals with hooves

• Cetacea and Sirenia: live in ocean; whales, dolphins, and manatees

• Proboscidea: Asian and African Elephants

Carnivora

Cetacea and Sirenia

Interesting Facts• Cows, sheep, goats, giraffes and others

have a four chambered stomach with a RUMEN which contains symbiotic bacteria

• Bats are the only mammals that can fly! The smallest bat weighs less than a penny!

• The Amur tiger is the largest cat in the world. From head to tail, it can grow up to thirteen feet long

• Cheetahs are the fastest land animals on earth.

• Cats can see up to six times better than humans in dim light

• A lion’s roar can be heard up to five miles away!

• There are over 40 species of kangaroos. The smaller kangaroos are called wallabies.

• A male kangaroo is called a boomer, a female kangaroo a flyer, and a baby kangaroo a joey. The name kangaroo came from the Aborigines through a mistake. An early European explorer asked an Aborigine what these strange hopping animals were, and the Aborigine replied kangaroo, meaning "I don't understand." The explorer thought he was naming the animal.

Primates• Large brain• Color Vision• Communication• Opposable thumb • Infant Care• Social organization

Hominids Australopithecus

Homo habilisHomo erectus

Homo sapien

Genus Australopithecus

• First human ancestor to live on the ground and walk on two legs– As evidenced by the Laetoli footprints

• Ape-like jaw

• Small brain

• Short stature

• Found only in South and East Africa

The Australopithecines

• A. anamesis 4 MYA

• A. afarensis 3.2 MYA “Lucy”

• A. africanus 2.5 MYA

• A. robustus 2 MYA

• A. boisei 2 MYA

Homo habilis “The Tool Man”

• Approx. 2.5 MYA

• Brain ½ size of modern human

• First to make and use stone tools and weapons

Homo erectus “The Upright Man”• Direct ancestor of

modern humans

• Widespread in Africa and Asia by 1 MYA

• Evidence of use of shelter and fire

Homo sapiens “The Wise Man”

• Most likely evolved from H. erectus as early as 400,000 years ago

• Greatly increased brain size

• Consisted of 2 groups– Neanderthal– Cro-Magnon/modern H. sapiens

Neanderthals

• Found in Neander Valley in Germany• Fossils found throughout Europe,

Middle East, and Asia from 150,000-30,000 years ago

• Large bodies and brains• Evidenced painting, religion, complex

social structure• “Cave man”

Cro Magnons and Fully Modern Humans

• First early modern H. sapiens appear about 130,000 years ago

• Thinner bones, smaller jaws, higher skull with little or no brow ridge, and larger brains

• Cave art shows complex religion and culture• Lived alongside Neanderthal for several

thousand years, but eventually out-competed them