Biology Lecture Slides PDF

Terminologies to Remember (Examples) It is important to become familiar and be able to define new and unfamiliar biological terminologies such as: ❖ Organism ❖ Unicellular ❖ Homeostasis ❖ Multicellular ❖ Prokaryote...

Terminologies to Remember (Examples) It is important to become familiar and be able to define new and unfamiliar biological terminologies such as: ❖ Organism ❖ Unicellular ❖ Homeostasis ❖ Multicellular ❖ Prokaryote ❖ Homeostasis ❖ Eukaryote ❖ Taxonomy ❖ Genome ❖ Domain ❖ Chromosome ❖ Kingdom ❖ DNA ❖ Protein ❖ Gene ❖ Emergent property ❖ Cells ❖ Tissues ❖ Membrane ❖ Organelle ❖ Natural selection 1  What is Biology? Biology is the scientific study of life. (Bio = life; logy = study) Biologists study living things or organisms, big and small. Now that we know what biology means… What is a living thing or organism? 2 What is a Living Organism? 3 Levels of biological organization ❖ Atoms come together to form molecules. ❖ Organelles are functional components of cells e.g. chloroplasts. ❖ The cell is the fundamental unit of structure and function. ❖ Cells come together to form tissues ❖ Tissues come together to form organs ❖ Organs come together to form organs systems ❖ Organs systems come together to form organisms ❖ Organisms collectively form populations, communities, and 4 ecosystems. All Living Things are made of Cells Cells = The smallest unit of structure & function. Simple, no nucleus or organelles 5  Prokaryotes  Oldest, smallest and simplest organisms  Unicellular – (uni “single” + cellular “cell”)  Bacteria (E. coli, Salmonella, Streptococcus etc)  Archaea are different to bacteria and found in extreme environments e.g. Pyrolobus fumarii found in hydrothermal vents at 235F. 6  Eukaryotes Larger, more complex cells that contain membrane-enclosed organelles (“little organs”) and a nucleus with DNA. Plants and animals have eukaryotic cells. Eukaryote cells have common features, but organelles can be specific to types of organism e.g. chloroplasts in plants. 7 Typical plant cell Typical human cell DNA is the genetic material of life Genetic information is inherited by offspring and encode information needed to establish the cells identity and function. Genetic information is encoded in four types of nucleotide: A- Adenine T- Thymine C- Cytosine G- Guanine 4 letter alphabet A always binds with T C always binds with G 8 Gene expression Genes are sequences of DNA that provide instructions for making proteins. Proteins are macromolecules that perform important functions in cells. 9 Cell Diversity Cardiac muscle cells Bacteria cells Nerve cells Plant cells 10  Taxonomic Classification Biological classification categorizes organisms into groups (taxa) based on similar features. American Black Bear 11 The Three Domains of Life 12  Domain- Bacteria Prokaryotic Unicellular Microscopic Other features: 1. Pathogens – cause disease 2. Symbiosis – benefit human hosts (gut bacteria) 3. Bioremediation – break down toxic compounds 4. Food products 5. Breakdown of dead organisms, animal waste & plant litter. 13  Domain- Archaea Prokaryotic Unicellular Microscopic Other features: 1. No known pathogens 2. Many are “extremophiles” (live in environment that are very hot, cold, salty, or etc.) 14  Domain- Eukarya Eukaryotic Unicellular or multicellular Microscopic or macroscopic 4 kingdoms (very diverse) 15  All Life is Related Through Evolution Process of evolution explains the diversity and unity of life. 16  Charles Darwin & Natural Selection “Descent with modification” As species adapt to different environments over time, they accumulate differences from their ancestors through natural selection. A modification has to be beneficial in terms of survival and reproduction to pass on those genes. 17 Darwin’s finches on the Galapagos Islands  Natural selection over long periods of time can give rise to multiple descendent species that are more adapted to a specific environments and food sources. 18 Survival of the Fittest Elephants normally have tusks that are useful & used for digging for water, foraging for food. Normally a small proportion of elephants are tuskless due to a random mutation. Proportion of tuskless elephants increased from 18.5% before the war to 50.9% after the war due to SELECTION PRESSURE due to poaching for ivory. 19