1. Biology – Premed 1 Windsor University School of Medicine Dr
Biology – Premed 1 Windsor University School of Medicine Dr. Veipu January 2015

2. Biology: The Science of Life

3. Biology is the science that studies living organisms:
What they are?
How they work?
How they interact?
How they evolve?

4. Response to the environment

5. Living things reproduce their own kind

6. How does a single tiny cell become a Tree?

9. Study of life extends from a global scale of the planet earth to the microscopic scale of cells and molecules
Biosphere –> Ecosystem –> Community Population –> Organisms –> Organs Tissues –> Cells –> Organelles –> Molecules

10. Individual living things are “Organisms”

11. All organisms share basic characteristics from a single-cell to a complex human
Basic features of living organisms are:
1. Highly organized and complex entities formed of one or more cells;
2. Carry out and control numerous chemical processes;
3. Acquire and use energy for metabolism;
4. Respond to changes in environment and maintain a constant internal environment;
5. Grow in size, develop;
6. Produce offspring similar to them;
7. Adapt to environmental changes and gradually evolve into new type of organisms.

12. Diversity of Life

13. Millions of organisms exist on earth --- Plants, animals, bacteria and viruses
Techniques have been developed for identification, naming and grouping of various organisms --- Biological Classification or “Taxonomy”

14. Taxonomy enfolds the following fundamental element:
Nomenclature --- Assigning of names to organisms based on the degree to which they share characteristics
Nomenclature can vary from one discipline to another, therefore a scientific name that is acceptable universally must identify and organism

15. Guidelines for Naming of Organisms:
(i) A scientific name generally has two words in Latin or derived from Latin irrespective of their origin
(ii) First word denotes the genus whereas the second one is for species
(iii) Names are printed in italics or are separately underlined to indicate their Latin origin
(iv) Generic name starts with a capital letter and the specific name with a small letter e.g. mangifera indica
(v) The name of the author is written in abbreviated form after the species name and is printed in Roman e.g. Mangifera indica Linn.
(vi) Each taxonomic group can have only one correct name
(vii) The name should be short, precise and easy to pronounce

16. Carolus Linnaeus (1707-1778), Swedish naturalist, referred to as “Father of Taxonomy”
First to propose an orderly system of classification of organisms
Linnaeus introduced a system of nomenclature of plants and animals known as “Binomial Nomenclature”

17. According to binomial nomenclature, the scientific name of a species consist of 2 parts; first part represents genus to which the species belongs; second part represents the identity of the species to which the individual belongs
E.g. Homo Sapiens
E.g. Pisum sativum ( Pea plants)

18. Taxonomic Hierarchy
To assign an organism an appropriate place in a system framework of classification
Taxonomic groups are arranged in a definite order from Higher to Lower categories

19. Taxonomic Hierarchy
The categories used in the classification of animals and plants:
Kingdom (Highest)
Phylum or Division
Class
Order
Family
Genus
Species (Lowest)
As we go from the lowest rank species towards kingdom the number of similar characteristics decreases

20. Decreasing Specificity
Increasing Specificity

21. SPECIES – Basic unit for understanding taxonomy as well as evolution
Group of individuals with similar morphological characters, which are able to breed among themselves and produce their own kind
KINGDOM – All organisms that share a set of distinguishing common characters
Plants are placed in Plant Kingdom while animals are placed in Animal Kingdom. This is the highest category of classification.
**Higher the category, lesser will be the number of common characteristics of organisms belonging to that category

22. Various other systems of classification were proposed from time to time:
Artificial System -- Classification based on one or a few superficial similarities such as shape or prominent features.
Another example would be categorizing into (i) can fly and (ii) cannot fly
Criteria considered for this type of grouping was simple and easy to follow
Natural System -- Classification based on natural affinities and uses more number of characters rather than a single character for determining the similarities.

23. Phylogenetic System – Based on evolutionary sequence as well as the genetic relationships among the organisms
Based on Darwin’s concept of Natural selection
Development of group of organisms or even an organism from its origin to the present state

24. Five Kingdom Classification
Monera
Protista
Fungi
Plantae
Animalia

25. Criteria for classifying into five kingdoms are complexity of cell structure, body organization, mode of nutrition, life style and the phylogenetic relationships
All multi-cellular, mobile, and heterotrophic organisms were assigned the Kingdom Animalia
Photosynthetic multi-cellular organisms were included in the Kingdom Plantae
Unicellular plants like algae and protozoans were taken out of the plant and animal kingdom and were included in a separate Kingdom Protista
Bacteria and multicellular blue green algae with prokaryotic cells were transferred from plant kingdom to a new kingdom called Monera

26. 1. Kingdom Monera (Prokaryotes)
Single-celled prokaryotic organisms like bacteria and photosynthetic blue green algae, and cyanobacteria
Nucleus and other organelles do not have enclosing membranes
Found in places like deep ocean floor, hot deserts, hot springs, survive in extreme temperatures, acidic/alkaline pH
Survive in anaerobic oxygen free conditions called Eubacteria (also known as “true bacteria”) and Archaebacteria (“ancient bacteria)
Bacteria are single-celled and take many form of shapes, good decomposers and help in recycling of nutrients

28. 2. Kingdom Protista
Both unicellular and multicellular organisms found in aquatic habitats
Algae (photosynthetic activity) and protozoa (e.g. Amoeba, Paramecium)
Membrane bound nucleus and may have cilia or flagella for their movements

30. 3. Kingdom Fungi
Fungi grow on decaying organic matter in moist and warm conditions
Can be single-celled (Yeasts) and also multi-cellular complex filamentous structures (Mycelia)
Reproduce by asexual spores or sexual reproduction

31. 4. Kingdom Plantae
Multi-cellular and photosynthetic forms of green plants
Rigid cellulose cell wall which prevents contraction
Lack locomotion
Photosythesis process by which the green plants synthesize food by utilizing water, minerals, and carbon dioxide with the help of green pigment chlorophyll and solar energy

32. 5. Kingdom Animalia:
Multi-cellular eukaryotes
No cell wall
Depend on plants for their basic requirements of food
Great diversity compared to other kingdoms

33. Microbiology --- Study of microscopic forms of life
Genetics --- Study of inheritance of organisms
Evolution --- Study of living systems as they change through time
Ecology --- Study of the relationships of organisms to their physical environment in which they live and to one another
Histology--- Study of the structural organization of living things at tissue level
Physiology --- Study of the normal functioning of animals and plants during life
Plant physiology --- Study of photosynthesis and transpiration
Cytology --- Study on the structure and composition of cells
Cell Biology --- Study correlating the structure of cells with their function
Molecular Biology --- Study of the composition of the organic and inorganic molecules of the cells and their interactions
Exobiology --- Study of life outside earth and within the solar system
Ethology – Study of animal behavior based on the observation, recording and analysis of how animals function