Class Notes on Birds and Mammals

Birds (Class Aves)

• Approximately 9,000 to 10,000 species.
• Many species are in decline due to habitat loss and feral cats, which are significant predators of birds (especially in places like Australia).
• Success factors for birds:
  • Flight
  • Endothermy (warm-bloodedness)
  • Shelled amniotic eggs
  • Efficient respiratory system
  • Four-chamber heart (closed circulatory system)
  • Intelligence (some birds, like New Caledonian crows, are remarkably intelligent, even outperforming chimpanzees and babies in certain tests).

Bird Origins

• Evolved from theropod dinosaurs.
• Archaeopteryx is a famous theropod fossil considered a potential ancestor of modern birds.

Bird Characteristics

• Endothermic.
• Bipedal (walk on two legs).
• Oviparous (lay eggs).
• Closed circulatory system with a four-chamber heart.
• Beaks without teeth.
• Highly efficient respiratory system, allowing for lung aeration during both inhalation and exhalation.

Efficient Respiratory System

• Birds aerate their lungs during both inhalation and exhalation.
• Combined with light but strong bones, this allows for long-distance flight.

Bird Flight Example

• Alaskan Bartailed Godwit flies nonstop from Alaska to New Zealand, a journey of 11,000 miles.

Red Flowers and Bird Pollination

• Flowers with red colors may be pollinated by birds because birds see red like humans do.

Excretory and Digestive Systems

• No urinary bladder.
• Produce uric acid as a waste product of protein breakdown (less toxic than urea, which mammals produce).
• Uric acid does not need to be diluted with water.
• Have a cloaca, an opening for waste removal, gamete release, and egg laying.

Digestive System

• Crop: a storage pouch for food.
• Gizzard: a stomach containing stones to grind food (since birds lack teeth).

Bird of Prey

• Birds of prey swallow their prey whole.
• They regurgitate indigestible parts (bones, feathers, fur) as pellets.
• Pellets can be analyzed to determine the bird's diet and health for bird identification.

Bird Flight Formation

• Birds fly in a V-shaped formation to reduce drag for birds behind the leader.
• Birds take turns being at the front to distribute the energy expenditure.

Poisonous Bird

• Pitohui bird, found in New Guinea, has poisonous feathers.

Vultures and Methane Leaks

• Vultures are attracted to the smell of sulfur added to methane (due to the rotten meat smell).
• Engineers can locate methane leaks by observing where vultures congregate.

Mammals (Class Mammalia)

• Approximately 5,000 species known, with the potential for more undiscovered species.
• Vertebrates that produce milk via mammary glands.
• Generally have fur or hair.
• Larger brain-to-body ratio compared to other vertebrates.
• Specialized teeth (incisors, canines, molars) for different functions.
• Endothermic (warm-blooded).
• Most mammals (99%) are viviparous (give live birth).

Mammal Groups

• Monotremes: Mammals that lay eggs (e.g., echidna and platypus).
• Marsupials: Mammals with a pouch (marsupium) where the premature fetus completes development by attaching to a nipple (e.g., kangaroos).
• Placental Mammals (Eutherians): Mammals with a placenta that connects the fetus to the mother, providing nourishment and waste removal (e.g., humans).

Primates (Order Primates)

• Includes lemurs, tarsiers, monkeys, and apes (including humans).
• Characteristics:
  • Pentadactyl hands (five digits).
  • Opposable thumbs.
  • Large brain-to-body size ratio.
  • Short jaws.
  • Omnivorous diet.
  • Binocular vision (eyes face forward).
  • Parental care of young.
  • Social behavior.

Primate Groups

• Prosimians: Most ancient primates, including lemurs, lorises, and tarsiers.
• New World Monkeys: Found in the Americas (Central and South America).
• Old World Monkeys: Found in Asia, Africa, and parts of Europe.

Prosimians

• Found in Madagascar, Comoro Islands, and Southeast Asia.
• Nocturnal.
• Lack prehensile tails.
• Have claws instead of nails.
• Limited binocular vision and typically lack color vision.
• Smaller brain-to-body ratio compared to other primates.
• Bicornuate uterus (uterus with two horns).

New World Monkeys

• Found in the Americas.
• Possess prehensile tails.
• Typically no sexual dimorphism (males and females look similar).
• Nostrils face sideways.
• Most do not have clear color vision (except for females).
• Arboreal (live in trees).

Old World Monkeys

• Found in Asia, Africa, parts of Europe.
• Lack prehensile tails.
• Show sexual dimorphism.
• Have color vision.
• Nostrils face downward.

Hominids (Family Hominidae)

• Includes "great apes": orangutans, chimpanzees, gorillas, and humans.
• Evolved from Old World monkeys about 25 million years ago.
• Paleoanthropology: Study of human origins.
• Hominids: Human-like species believed to have evolved from ancestors called Australopithecus.
• Two genera:
  • Australopith.
  • Homo.

Australopith

• Earliest known hominid fossils.
• Possess traits between ape-like and human-like characteristics.
• May have evolved about 3-7 million years ago.
• Famous fossil: "Lucy" (Australopithecus).

Homo

• Homo Habilis:
  • The earliest member of the genus Homo.
  • Habilis means "tool-using man."
  • Found stone tools.
• Homo Erectus/Homo Ergaster:
  • Considered the same species.
  • First fully bipedal hominid with a relatively large brain.
  • First hominid believed to have left Africa.
• Homo Neanderthalensis:
  • Lived in Europe, Near East, Middle East.
  • Extinct.
  • May have interbred with Homo sapiens.
  • Outcompeted by Homo sapiens.
• Homo Sapiens:
  • Earliest evidence dates back 60,000 to 200,000 years ago.
  • Ancestors of modern Asians and Europeans.

Genetic similarity

• Homo sapiens are 99.9% genetically identical.
• Humans are more genetically similar to each other than chimpanzees are to other chimpanzees.
• Africans have more genetic diversity compared to non-Africans because Homo sapiens evolved in Africa.

Genetic Differences

• 85% of the 0.1% difference are differences that have nothing to do with race or ethnicity, meaning that these are different that any two Thai or any two Koreans can be different from one another.

Examples of Genetic Similarity

• Genetic ancestry and physical appearance may not align. For example, Ethiopians are genetically more similar to Armenians than to Barents people, even though people often stereotype Ethiopians as Africa and therefore will put them to William (an African) as being more close together.

Unique traits of homo sapiens

• Upright posture and bipedal motion.
• Larger brains compared to other primates.
• Language capabilities.
• Tool use.
• Shortened jaws.

Baboons language connection

• Studying the gelada baboons to see if perhaps this could be where the origin of of communication of talking occur.

Example Questions Included

• What are the general terms and diagnostic of manuals?
• Which of these mammals give birth to a premature fetus?
• Which group of primates processes the following: prismatic vision, no prehensile tails, sexual dimorphism, and nostrils facing downward?