Section outline

  •    

    Hello....! Nice to meet you all here and thanks for joining me in this short trip to understand more on animals, particularly, the mammals! 


    There are millions of animal species on Earth. While many animal species were extincted over the geological years, new species are born now and then too, evolve from our existing ancestors. So you might now ask....

     Why there are so many types of animals exists in this world? 

    How do they look like?

    Why do each type of animal evolve into its current form?

    How to differentiate and classify such a big Kingdom Animalia on Earth? 

    These are good questions! I will try my best to answering your questions such as above ones, in addition to explaining and showing you more about animal in this course, named Animal Diversity, offering as a first year course for Biology Program by School of Distance Education, Universiti Sains Malaysia.


  • Phylum Chordata: Class Mammalia

    Suggested Self-learning Activities and Time:

    Asynchronous learning:
    • E-Kuliah (3 hours)
    • Forum/discussion (2 hours)
    • Exercise (2 hours)
    • Preparation for lab practical (2 hours)

    Synchronous learning:
    • Webex live (1 hour)
    • Lab practical (1 hour)

  • Topic's Learning Outcomes

    At the end of this webex topic, students should be able to

    1. explain the common characteristics, adaptation and evolution, surviving issues/ human-animal conflicts of class mammalia.

  • Topic's Introduction

    I am sure all of us are familiar about mammals, some even have some of the mammal species accompany us as pets. Can you list three mammal species that you can come across in your daily life in Self-learning activities? What are the characteristics that make you label them as mammals?

    Mammalia is the last vertebrate class and of all animals we are going to learn in this course. Mammalia can be found live on land and in water, one of the mammalian order even evolves to have the ability to fly. We are going to explore the uniqueness and the diversity of mammalia since their most recent common ancestor, which was the pelycosaurs. These uniqueness included our skin which cover by hair, and is evolve to have various types of glands, and some even with horns and antlers growing on their head. Some other extraordinary features such as the ability to navigate and communicate using ultrasound, ways of baring and raising their youngs in monotremes and marsupials, common mammalians' gestation and lactation periods will also be discussed.

  • Main Learning Materials

    Read the notes and watch the pre-recorded lectures below. Remember to visit Self-learning activities, feel free to join the topical forum, ask questions and participate in each question's discussion with your friends! 

    Remember to revise what you've learn in this topic by trying the questions at Self Evaluation. 

    Last but not least, you can add on the Glossary list for this topic, as another mean of revision.

    Happy exploring and learning!


  • Self-learning Activities

    Hi all,

    After going through the learning materials and our synchronous online lecture, let's explore this topic further! Feel free to participate in the following activities or forums according to each subtopic to explore now!

  • Self-Evaluation


    Whoops......Welcome here! Try the topical quizzes in Quiz section of Coursework for your revision.

    See you there!


  • Additional Learning Materials

    This section is not compulsory, just for your own interests. The Self-learning and Teaching time  (SLT) for this section is not included in the required SLT of this course.

    • resource icon
      File
      The Biodiversity of Penang Hill - Chapter 4 File
      View

      This is a book chapter published after Penang Hill expedition Bioblitz 2017. This is the chapter of the book that focus on the fauna diversity of Penang Hill, outcome of Penang Hill Bioblitz 2017.

    • folder icon
      Folder
      The bat diversity of Peninsular Malaysia Folder
      View

      These are the findings from my studies since year 2008. Feel free to read through if you are curious and interested in bats!

    • url icon
      URL
      Bat survey during Bioblitz Penang Hill 2017 URL
      View

      Watch this video to follow us in our bat survey at the peak of Penang Hill back in 2017 during the Bioblitz 2017 expedition.

    • url icon
      URL
      Malaysia's Last Tigers - Documentary by Rimau Ngo URL
      View

      Watch this latest video to understand the survival challenges facing by our iconic King in our forests - the tigers, and how important it is to maintain a good biodiversity, specifically, fauna diversity, in order to maintain a healthy tiger population. In turns of protecting the tigers, we saved our precious tropical rainforest. 

  • Summary

    This section is purely adopted from our textbook (Hickman, C., Keen, S., Larson, A., Eisenhour, D. & I’Anson, H, (2014). Integrated Principles of Zoology (18th edition). McGraw-Hill Publishing Company), according to our course learning objectives and content.

    • Mammals are endothermic vertebrates whose bodies have hair and who nurse their young with milk.
    • The approximately 5700 species of mammals descend from the synapsid lineage of amniotes that arose during the Carboniferous period of the Paleozoic era. Their evolution is traced from pelycosaurs of the Permian period to therapsids of the late Permian and Triassic periods of the Mesozoic era. One group of therapsids, the cynodonts, gave rise during the Triassic period to mammals.
    • Mammalian evolution was accompanied by the appearance of many important derived characteristics, among these an enlarged brain with greater sensory integration, high metabolic rate, endothermy, heterodont teeth, three middle ear bones, and many changes in the skeleton, including a position of the legs under the trunk (instead of to the side of the trunk). Most of these changes supported a relatively active lifestyle.
    • Mammalian diversification began during the Cretaceous period; by the Eocene epoch of the Cenozoic era, most modern orders had appeared.
    • During the Pleistocene ice ages, many regions had a great diversity of large-bodied mammals (megafauna). Most of these went extinct at the end of the Pleistocene epoch, probably due to a combination of habitat changes and hunting by humans.
    • Living mammals are in three clades: Monotremata (egg-laying mammals), Metatheria (marsupials), and Eutheria (placentals).
    • Mammals are named for the glandular milk-secreting organs of females (rudimentary in males), a unique
      adaptation that, combined with prolonged parental care, buffers infants from demands of foraging for
      themselves and eases the transition to adulthood.
    • Hair, the integumentary outgrowth that covers most mammals, serves variously for mechanical protection, thermal insulation, protective coloration, and waterproofing.
    • Many herbivorous mammals have horns (primarily composed of keratin) or antlers (composed of bone).
    • Mammalian skin is rich in glands: sweat glands that function in evaporative cooling, scent glands used in social interactions, and sebaceous glands that secrete conditioning oil. Mammary glands, for which mammals are named, secrete milk to feed the young.
    • Placental mammals have deciduous teeth that are replaced by permanent teeth (diphyodont dentition). Mammals have diverse (heterodont) dentition, including four kinds of teeth—incisors, canines, premolars, and molars. These are highly modified in different mammals for specialized feeding tasks, or they may be absent.
    • Mammals’ food habits strongly influence their body form and physiology. Insectivorous mammals have pointed teeth for piercing the exoskeletons of insects and the integument of other small invertebrates. Herbivorous mammals have specialized molars and premolars for grinding cellulose and silica-rich plants and have specialized regions of the gut for harboring microorganisms that digest cellulose. Carnivorous mammals have specialized jaw muscles and teeth for killing and removing flesh from their prey, mainly herbivorous mammals. Omnivorous mammals feed on both plant and animal foods and have a variety of tooth types.
    • Some marine, terrestrial, and aerial mammals migrate; migrations of some, such as whales, fur seals, and caribou, are extensive. Migrations usually are made toward climatic conditions favorable for finding food, mating, or rearing young.
    • Mammals with true flight, the bats, are mainly nocturnal and thus avoid direct competition with birds. Most employ ultrasonic echolocation to navigate and to feed in darkness.
    • Monotremes, of the Australian region, are the only mammals that retain the ancestral trait of egg-laying. After hatching, the young are nourished with their mother’s milk. All other mammals (therians) are viviparous.
    • Embryos of marsupials have brief gestation periods, are born underdeveloped, and complete their early growth in the mother’s pouch, nourished by milk.
    • The remaining mammals are eutherians (“placentals”), mammals that develop a sophisticated placental attachment between mother and embryo through which an embryo is nourished for a prolonged period.
    • Mammal populations fluctuate due to both density-dependent and density-independent causes, and some mammals, particularly rodents, may experience extreme cycles of abundance in population density.
    • Humans domesticated dogs about 15,000 years ago. Domestication of additional species as pets, beasts of burden, or livestock occurred later; these species included cattle, horses, goats, cats, and camels, among others.
    • Some mammal species negatively affect humans by devouring our food or serving as vectors for diseases.
    • Humans are primates, a mammalian group that descended from a shrewlike ancestor. The common ancestor of all modern primates was arboreal and had grasping fingers and forward-facing eyes capable of binocular vision.
    • Primates diversified to form two groups: (1) lemurs and lorises; and (2) tarsiers, monkeys, and apes (including humans). Chimpanzees and bonobos together form the sister group of humans.
    • The earliest humans appeared in Africa 7 to 10 million years ago and gave rise to several genera of early humans, including Ardipithecus, Australopithecus, and Paranthropus, which persisted for about 3 million years. These early humans were shorter and smaller-brained than modern humans, but were bipedal.
    • Homo habilis, the first maker of stone tools, appeared about 2.8 million years ago, and coexisted with some
      of the early humans.
    • Homo erectus appeared about 1.9 million years ago and spread throughout Africa, Europe, and Asia. It was
      eventually replaced by Neandertals, Homo neanderthalensis, and modern humans, Homo sapiens.

  • Keywords

    What are the new words that representing this topic that you've pick up from? Just add it here, as a revision and a sharing with your fellow mates.

  • References

    • Hickman, C., Keen, S., Larson, A., Eisenhour, D. & I’Anson, H, (2014). Integrated Principles of Zoology (16th edition). McGraw-Hill Publishing Company.