Biology Exploring Life Biology is the scientific study

Biology: Exploring Life Biology is the scientific study of life

Biological Hierarchy of Organization: Life can exist here http: //www. ux 1. eiu. edu/~cfruf/images/bio 3002/els_le 2. jpg

Hierarchy of Life; Organization levels Molecules are atoms held together by chemical bonds (ex: DNA, protein) Organelles are membrane-bound structures with specific functions for & w/in some cells Cells are the smallest unit of life; separates the environment with a membrane Tissues are layers of cells to perform a specific function Organs are groups of tissues working together to perform a specific function

Hierarchy of Life; Organization levels, cont’d Organ Systems are organs grouped together to perform a function Organism is a living thing within a population Population: the same species living within a specific area Community: many groups of different species within an ecosystem Ecosystem: contains biotic (living) factors & abiotic (nonliving) factors within a specified area/community Biosphere: all ecosystems of the Earth

Hierarchy of Life; Organization levels, cont’d • From most specific to general: Atoms Molecules Organelles Cells Tissues Organ Systems Organism Population Community Ecosystem Biosphere *Blue color denotes living/biotic

Cycle of Nutrients and Energy: http: //www. globalchange. umich. edu/globalchange 1 /current/lectures/kling/ecosystem/zebra 2. gif

Organism Interaction, Matter, and Energy • An Ecosystem contains 3 categories of organisms: – Producers (autotrophic organisms like plants, algae, and some bacteria): perform photosynthesis (absorb H 2 O, CO 2 & sunlight & convert these to sugar and O 2) – Consumers (heterotrophic organisms like animals): organisms that eat plants and other animals. These take in O 2 and release CO 2, while releasing waste into the environment. – Decomposers (heterotrophic organisms like bacteria and fungi) that break down wastes and dead/decomposing organisms, while recycling matter into the environment (which the producers use).

Organism Interaction, Matter, and Energy, Cont’d • Ecosystems have 2 major processes: Recycling chemical nutrients and energy flow. • Recycling chemical nutrients: O 2, CO 2, H 2 O, etc. go from the air and soil to producers to consumers to decomposers and then back to the air and soil. These are recycled! • Energy Flow: solar energy is absorbed by producers & converted to chemical energy thru photosynthesis. – Chemical energy is passed thru many organisms (consumers: primary to secondary, etc) and then finally to decomposers. – At every pass, some energy is LOST as heat. – Energy flows THROUGH the ecosystem (enters as light; exits as heat).

Cells, the structural & functional unit of life • The cell is the basic unit of life, the lowest level of structure at which the properties of life emerge. These correlate structure = function! • The cell: – Regulates its internal environment (homeostasis) – Takes in & uses energy – Responds to its environment – Develops & maintains a complex organism – Reproduces (give rise to new cells)

Cells, the structural & functional unit of life, Cont’d Characteristics of a Cell: • Enclosed in a membrane (which regulates the flow/regulation of materials in and out of the cell) • Contains DNA (genetic material), cytoplasm, ribosomes 2 types of cells: • Prokaryotic Cell (Kingdoms Archaebacteria and Eubacteria): bacteria; small and simple cells • Eukaryotic Cell (All other Kingdoms): plants, animals, protists, and fungi. – Have organelles (functional compartments with specific functions) – Have a nucleus that contains DNA

Prokaryote: Eukaryote: http: //www. ichristianschool. com/biology/images/prokaryote. jpg http: //faculty. uca. edu/~johnc/eukaryote. jpg

Unity of Life • The continuity of life is based on ALL living things have DNA (genetic material). • Genes (inheritable material) are made up of DNA sequences – DNA is 2 chains coiled together to form a double helix (structure) – Nucleotides= building blocks; these contain nitrogenous bases attached: adenine (A), thymine (T), guanine (G), or cytosine (C). • All forms of life contain the same genetic code; the sequences (order) is different. This results in different genes. http: //www. scq. ubc. ca/wp-content/dna. gif

Unity of Life, Cont’d – CHARACTERISTICS OF LIFE: In addition to Genes, all organisms have: • Order (level of organization) • Metabolism (all chemical reactions) • Regulation (a. k. a. homeostasis, or control of the internal environment to sustain life) • Growth (increase in size) • Development (change in form) • Energy processing (ability to use & transform, or transduce, energy) • Response to Environment (both internal & external stimuli) • Reproduction (make more like themselves) • Evolutionary Adaptation (traits that are best suited to the environment that are passed on to the offspring; ie. camouflage, spots, etc)

Diversity of Life – Classification of organisms • A species is the smallest category of organisms (most specific) – share the most common characteristics – can reproduce with each other. • Taxonomy is the branch of Bio which names & classifies organisms according to characteristics and similarities – molecular, genetic, biochemical, morphological, evolutionary phylogenies/histories, etc. This is completed from broadest category to most specific: Domain Kingdom Phylum Class Order Family Genus Species

http: //upload. wikimedia. org/wikipedia/commons/9/96/S cientific_classification. png http: //www. lesley-smitheringale-fine-art. com/wpcontent/uploads/2008/05/atlas-moth-scientific-classification. jpg

There are 3 Domains: Domain Bacteria or Eubacteria, Domain Archaea, Domain Eukarya • Domain Bacteria or Eubacteria (have peptidoglycan in their cell walls) • Domain Archaea (live in extreme environments, like hot or salty places, or anaerobic environments) – BOTH Bacteria and Archaea are prokaryotic, are bacteria, are unicellular & microscopic, and are found in Kingdoms Archaebacteria and Eubacteria. • Domain Eukarya – Include all eukaryotic organisms (have organelles & a nucleus). – Include protists (Kingdom Protista). These are uni or multicellular. Ex. Include algae and protozoans – Include plants (Kingdom Plantae), which have a rigid cell wall and perform photosynthesis. – Include animals (Kingdom Animalia) which lack a cell wall and must consume food – Include fungi (Kingdom Fungi) which are yeast, mushrooms and molds that decompose dead organisms. – Protista, Plantae, and Fungi are generally separated by their modes of nutrition.

Domain Bacteria: Electron Micrograph of E. Coli http: //www. foxnews. com/images/250204/0_61_bac teria_e_coli. jpg Domain Arachaea: Image of Methanococcus jannaschii http: //www. biology. iupui. edu/biocourses/ n 100/images/dmethanopyrus. jpg

A Micrograph of Euglena (Protist): http: //faculty. clintoncc. suny. edu/faculty/Michael. Gregory/ files/Bio%20102%20 lectures/Evolution, %20 Speciation, %20 Taxonomy/specia 12. gif Plant: Palm Tree http: //www. untiredwithlovin g. org/palm_tree_2. jpg Fungi: Death Cap, Death Angel Mushroom http: //www. gencat. cat/especial/bolets/i mg/toxics/farinera_borda 1. gif http: //www. biologyreference. com/ images/biol_04_img 0381. jpg Animal: Bull Shark http: //animals. nationalgeographic. com/static files/NGS/Shared/Static. Files/animals/image s/primary/bull-shark. jpg

Evolution Explains the Unity & Diversity of Life • Darwin wrote On the Origin of Species by Means of Natural Selection which supported the idea of evolution = species alive today are descendants of ancestral species (a. k. a. ‘descent with modification’). • This means descent from a common ancestor. This supports the unity of life. • Darwin’s idea supported the diversity of life (modification as species diverged). http: //www. goodschist. com/wp-content/gallery/charlesdarwin/Darwin_age 29. JPG

Darwin recognized that variations existed within organisms. – These enhance their ability to survive AND reproduce (this is the essence of evolution by means of natural selection). • These successful adaptations are the result of evolution, the process of change over time which has transformed life on Earth.

Evolution Explains the Unity & Diversity of Life, Cont’d • Darwin proposed that evolution occurred through Natural Selection (NS): – Recognized (observed) that w/in a population, variations exist AND in many cases more organisms were produced than could survive (to produce their own offspring); this was an overproduction of offspring. – From these observations, he suggested that the individuals who were likely to survive AND reproduce were best suited to the environment; they inherited the best traits and would pass these traits on to their offspring. – Overtime, the best suited (or favorable) traits would accumulate within a population. This could eventually lead to a new species.

Evolution Explains the Unity & Diversity of Life, Cont’d • The environment ‘selects’ for individuals w/certain traits meaning there is an unequal reproductive success. This is Natural Selection (NS). • The product of NS = evolutionary adaptation, or the accumulation of favorable traits in a population over time. • NS is an editing process that works on heritable variations which are exposed to environmental factors that favor reproductive success. • Major alteration of a species could occur from many small changes w/in a population. Darwin proposed that a new species could arise due to these gradual changes over long periods of time.

Scientific Method – terms that have different meanings in Science versus mainstream use: • Science means “to know. ” “Science can neither prove nor disprove the existence of a God or supernatural power- for such questions are outside the bounds of science. ” • A hypothesis is a possible (plausible) explanation based on observation (that can be tested). Mainstream use : an “educated guess” Theories in science: • A theory is a hypothesis that has been tested repeatedly and is generally regarded as true. Examples: Theory of Evolution, Theory of Relativity, Atomic Theory, Cell Theory. Mainstream use: just an “idea”

The Evolution Connection Evolution is the CORE theme in biology. • There are many differences (and similarities) in DNA among individuals, populations, and species; this reflects evolutionary change. • Through the Human Genome Project (HGP), scientists have been able to ID & construct the DNA base sequences of many species. – allows comparative & functional genomics (the ability to identify common genes, search for new medical treatments, and more using DNA technology). • DNA differences in humans is used in forensics: this is DNA fingerprinting or DNA profiling and is used to convict or exonerate, determine paternity, or identify remains.

Evolutionary knowledge can help scientists in the understanding: • Vaccinations • HIV drugs • virus evolution • the development of antibiotic-resistant bacteria & pesticide-resistant crops • how to help endangered species