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An Introduction to Zoology

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1 An Introduction to Zoology

2 Zoology is the study of the entire animal kingdom
I. Basics Zoology is the study of the entire animal kingdom zo- {New Latin} = animal; -ology = study of, knowledge B. Zoology is a subset of biology

3 How do you tell if something is living?
C. What is Biology? Biology is the study of life! Living things are called organisms and include bacteria, protists, fungi, plants, & animals How do you tell if something is living? Characteristics of Life

4 1. All organisms are made of cells.
Cells are the smallest living unit of an organism Simplest cells are called Prokaryotes Complex cells are called Eukaryotes

5 2. All living organisms require a food source for energy.
Autotrophs can make their own food (aka producers)

6 Heterotrophs can NOT make their own food (aka consumers)

7 Many chemical reactions are involved in acquiring energy
Metabolism – the sum total of all chemical reactions which build up and tear down complex molecules in order to generate cellular energy

8 3. All living organisms must maintain homeostasis.
Homeostasis – maintaining a stable steady state both internally and externally example: pH, temperature, water balance, adaptations to environment

9 4. All living organisms reproduce.
Organisms reproduce to pass on genetic traits to their offspring, producing new organisms like themselves.

10 Two Types of Reproduction
Sexual Reproduction Involves 2 parents Egg and sperm  zygote (fertilized egg) Zygote contains hereditary information from both parents

11 Asexual Reproduction Involves a single organism
Cell divides by binary fission Offspring IDENTICAL to parent

12 All living organisms grow & develop.
Organisms grow as the result of cell enlargement and cell division Cell division is the formation of two cells from a preexisting cell

13 6. All living organisms contain DNA.
DNA (deoxyribose nucleic acid) contains genetic material passed from one generation to the next.

14 7. All living things respond to stimuli
Ex. light, heat, chemical and mechanical changes Results in adaptations - changes in the structure or functioning of an organism that makes it better suited to its environment

15 Characteristics of Life
All are made of cells All require food and energy All maintain homeostasis All reproduce All grow and develop All contain DNA All respond to stimuli All adapt and evolve over time

16 II. What is an animal? Animals are organisms that are eukaryotic, multicellular, heterotrophic, and lack cell walls Over 95% of all animals are invertebrates, do not have a vertebral column The other 5% are vertebrates

17 III. Components of Zoology
Invertebrate Zoology – is the study of animals without a back bone (vertebral column) 1. most are soft bodied 2. some have an exoskeleton or shell

18 B. Vertebrate Zoology – is the study of animals that have a back bone (vertebral column)
1. higher level of development 2. have internal support system made of bone or cartilage 3. All in the Phylum Chordata

19 Specialties or sub-disciplines of Zoology
1.       Study of one-celled animals –protozoology 2.       Study of mollusks – malacology 3.     Study of insects – entomology 4.       Study of spiders – arachnology 5.      Study of birds – ornithology 6.    Study of reptiles and amphibians – herpetology 7.    Study of fish – ichthyology 8.    Study of mammals – mammalogy

20 Morphology – the study of the shape, form, and structure of animals and their parts.
Comparative Anatomy – study of the similarities and differences in the anatomy of different groups of animals 1. homologous structures 2. analogous structures 3. germ layers – cell layers during development

21 E. Taxonomy – the science of naming and classifying organisms on the basis of their evolutionary closeness to other organisms. 1. Use binomial nomenclature 2. Systamatics – science that describes relationships among organisms 3. Phylogeny or Cladistics which shows evolutionary relationships to other animals

22 There are about 1.5 million named animal species.
These are divided into approximately 34 phyla, based on the complexity of their body. All 34 phyla contain invertebrates, even the phylum Chordata. 94% of all animal species are invertebrates. 82% of all animal species are Arthropods. 3% of all animals are in the phylum Chordata. 0.03% of all animals are mammals.


24 The Commonality of Living Things
A. All are composed of cells (animals are multicellular, heterotrophic organisms) 1. Cell Theory is a basic tenet of biology. The cell theory states that: a) all living things are composed of cells b)  the cell is the fundamental unit of life c)   all cells in our modern atmosphere and conditions must come from pre-existing cells (“omni cellula a cellula” ….Virchow)

25 B. Genetic Unity 1. All organisms contain heredity information in the same molecule, a nucleic acid called DNA 2.  The DNA of living organisms is remarkably similar. The more closely related two organisms are to each other, the more similar is their DNA 3. The DNA: basis for genetic continuity of organisms; is also the source of physical diversity through the process of mutation

26 C. Organisms share a common genetic history – common ancestry
1. Evolution (unifying theory of biology) is the gradual change with in a population of organisms over very long periods of time.

27 2. Evidences for evolution:
a) diversity of living and extinct species b) Fossil record…study of paleontology c) Comparative embryology – the embryonic development of an organism mirrors somewhat its evolutionary history d) Study of DNA and its relatedness between species e) Comparative anatomy




31 e) Molecular biology and the study of proteins in organisms
f) Biogeography – the study of the distribution of plants, animals, and fossils throughout the world (Nearctic, Neotropical, Palearctic, Oriental, Australian, Ethiopian) g) Comparative Anatomy 1) homologous structures – structures that are alike anatomically, but function differently 2) analogous structures – structures that have different developmental and anatomical origins, but function similarly (convergent evolution) 3) vestigial structures – anatomical structures that were useful during some time in the species history, but no longer are functional



34 D. Organisms share same environmental pressures
1.  Organisms must adapt to existing surrounding conditions or face extinction 2.   Ecological problems a)   Pollution of air and water sources b)   Human overpopulation c)   Loss of habitat d)   Global warming issues from human activities e)   Over fishing and over hunting f)   Use of non-renewable fuels (oil, coal, petroleum) g) Decline of rainforests

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