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Biology. Biology: Exploring Life Biology is the scientific study of life. Biological Hierarchy of Organization:. Life can exist here. http://www.ux1.eiu.edu/~cfruf/images/bio3002/els_le2.jpg. Hierarchy of Life; Organization levels. - PowerPoint PPT Presentation
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http://www.ux1.eiu.edu/~cfruf/images/bio3002/els_le2.jpg
Biological Hierarchy of Organization:
Life can exist here
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 Organs Organ Systems Organism Population Community Ecosystem Biosphere
*Blue color denotes living/biotic
Cycle of Nutrients and Energy:
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/ecosystem/zebra2.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 H2O, CO2 & sunlight & convert these to sugar and O2)
– Consumers (heterotrophic organisms like animals): organisms that eat plants and other animals. These take in O2 and release CO2, 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: O2, CO2, H2O, 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:
http://www.ichristianschool.com/biology/images/prokaryote.jpg
Eukaryote:
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/Scientific_classification.png
http://www.lesley-smitheringale-fine-art.com/wp-content/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_bacteria_e_coli.jpg
Domain Arachaea: Image of
Methanococcus jannaschii
http://www.biology.iupui.edu/biocourses/n100/images/dmethanopyrus.jpg
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Evolution,%20Speciation,%20Taxonomy/specia12.gif
A Micrograph of Euglena (Protist):
http://www.biologyreference.com/images/biol_04_img0381.jpg
Plant: Palm Tree
http://www.untiredwithloving.org/palm_tree_2.jpg
Fungi: Death Cap, Death Angel Mushroom
http://www.gencat.cat/especial/bolets/img/toxics/farinera_borda1.gif
Animal: Bull Shark
http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/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/charles-
darwin/Darwin_age29.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.