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A of life; Origin and Classification of Life Biol 120 Dr Ariyibi
Chapters 1,25 & 26 Register online at www.masteringbio.com Course Title: Organismic Biol 120 Course ID: DRARIYIBI41122 Outline Defining Life - Emergent Properties
Materials and Energy Reproduction and Development Adaptations and Natural Selection Biosphere Organization Human Population Biodiversity
Taxonomy Scientific Method Defining Life All living things are comprised of the same chemical elements and obey the same physical and chemical laws as nonliving objects. A cell is the smallest, most basic unit of life. Tissue, Organs, Organ Systems, Organism Population, Community, Ecosystem, Biosphere
Defining Life Emergent Properties Each level of organization is more complex and has properties beyond the preceding level.
Each new level of organization has emergent properties due to interactions between different parts of the whole.
Materials and Energy Energy is the capacity to do work. Metabolism encompasses all the chemical reactions that occur in a cell. Homeostasis - Maintenance of internal conditions within certain boundaries.
The sun is the ultimate source of energy for nearly all life on the planet. Photosynthesis
Reproduction and Development Asexual Reproduction: Unicellular organisms Sexual Reproduction: In most multicellular organisms, reproduction begins with the union of two gametes from different individuals. Organizational instructions encoded in genes. Composed of DNA
Adaptations Adaptation - Any modification that makes an organism suited to its way of life. Over time, organisms become modified by the process of natural selection. The unity of characteristics between different types of organisms suggests that all living things are descended from a common ancestor. Descent with modification
Biosphere Organization All members of a species within a particular area are known as a population. A collection of interacting populations is known as a community. A collection of communities make up an ecosystem. Ecosystems are characterized by chemical cycling and energy flow, both originating from photosynthesis.
Human Population The human population tends to modify existing ecosystems for its own purpose.
Human beings depend on healthy ecosystems for food, oxygen, medicines, other raw materials, as well as the benefits of various ecosystem processes.
Biodiversity Biodiversity is the total number of species, the variability of their genes, and the ecosystems in which they live. Extinction is the death of a species or larger taxonomic group. Some suggest that preservation of ecosystems is the primary bioethical issue of our time.
Scientific Names Binomial First word represents genus. Second word is specific epithet of a species within the genus. Genus species
Universal Latin-based Process of Science Observation Any phenomenon can be more fully understood by observation.
Hypothesis Use of inductive reasoning to form an explanation for the observed phenomenon.
Process of Science Experiments Use of inductive reasoning to form an appropriate experimental design. Control Group Model (Test group)
Data Observable, objective results of an experiment. The greater the variance in the data, the greater the probability of error.
Conclusion Data must be analyzed in order to reach a conclusion as to whether or not the hypothesis is supported. Findings must be reported in scientific journals so methodology and data are open for inspection and repetition.
Scientific Theory Scientific Theory - Joins together two or more related hypotheses. Supported by a broad range of observations, experiments, and data.
Scientific Principle / Law - Theory, or set of theories, generally accepted by an overwhelming number of scientists.
Law of motion and law of gravity Controlled Study Experimental Variable Factor of the experiment being tested.
(effect of nutrition on growth) Dependent Variable Result that occurs due to the experimental variable. (How nutrition affects growth) Classic Experiment
Hypothesis Prediction Experimental Design Control Group Test Groups
Results Conclusion Outline Primitive Earth Origin of First Cells
Fossils The Precambrian The Paleozoic The Mesozoic The Cenozoic Continental Drift Mass Extinctions The Primitive Earth Primitive atmosphere most likely consisted of water vapor, nitrogen, and carbon dioxide, with small amounts of hydrogen and carbon monoxide. Little or no free oxygen. Originally too hot for anything but water vapor to form. Earth cooled and water vapor condensed to liquid water.
Monomers Evolve Stanley Miller (1953) conducted an experiment to show the first organic molecules could have been produced from primitive atmospheric gases in the presence of strong energy sources. Polymers Evolve Monomers join to form polymers in the presence of enzymes. Protein-First Hypothesis assumes DNA genes came after protein enzymes arose. RNA-First Hypothesis suggests only RNA was needed to progress toward formation of the first cell or cells.
Protocell Evolves Protocells would have been precursors to the first true cells. A protocell is a structure with a lipid-protein membrane that carries on energy metabolism. ex Semipermeable-type boundary may form around droplets. Liposomes form in liquid environments.
Fossils
Fossils are remains and traces of past life. Great majority are found embedded in, or recently eroded from, sedimentary rock. Sediment becomes a stratum. Recognizable layer in stratigraphic sequence. Paleontology is the study of the fossil record.
Relative Dating of Fossils change Strata their character over great distances. A stratum of the same age tends to contain the same fossil. Helps geologists determine relative dates of the strata despite upheavals.
Absolute Dating of Fossils One absolute dating method relies on radioactive dating techniques. All radioactive isotopes have a particular half-life. Length of time it takes for half of the radioactive isotope to change into another stable element. Compare radioactivity of a fossil to that of a modern sample of organic matter.
The Precambrian First cells came into existence. Prokaryotes ex. Cyanobacteria added oxygen to the atmosphere Eukaryotic Cells Arise
Eukaryotic cell arose about 2 billion years. Nearly always aerobic and contains nucleus as well as other membranous organelles.
Multicellularity arose approximately 1 billion years later. The Paleozoic The Paleozoic era lasted over 300 million years. Contained three major mass extinctions. Disappearance of a large number of species, or a higher taxonomic group, within a relatively small time interval.
Cambrian Animals and plants (mostly aquatic)
High Cambrian diversity may be due to the evolution of outer skeletons. Invasion of Land (Paleozoic era) Plants Seedless vascular plants.
Invertebrates Outer skeleton and jointed appendages of arthropods are adaptive to living on land.
Vertebrates Evolution of fishes began .
The Mesozoic Era Evolution of many plants and animals. Nonflowering seed plants became dominant. Reptiles became abundant Dinosaurs achieved enormous size. First Mammals appear. The Cenozoic Era
Mammals at the end of the Mesozoic era, moved into habitats left vacant by the demise of dinosaurs. Flowering plants already diverse and plentiful. Primate evolution began. Factors That Influence Evolution
Continental Drift Positions of continents and oceans are not fixed. Modern mammalian biological diversity is the result of isolated evolution on separate continents.
Continental Drift Plate Tectonics
Movements of Earths crust which is fragmented into slablike plates that float on a lower hot mantle layer.
Classification of Living Things Outline Taxonomy Binomial System
Species Identification Classification Categories Phylogenetic Trees Tracing Phylogeny
Cladistic Systematics Phenetic Systematics Classification Systems Taxonomy Classification is usually based on understanding of how organisms are related to one another through evolution. Natural system reflects the evolutionary history of an organism. Taxonomy began with Greeks and Romans. Aristotle(Greek)
Binomial System In mid-eighteenth century, Linnaeus developed the binomial system of naming species. First word is genus(Group of related species). Second word specific epithet refers to one species within genus. A species is designated by the full binomial name (Genus species).
Species Identification Definition of Species Biological definition of a species rests on recognition that distinctive characteristics are passed from parent to offspring.
When a species has a wide geographic range, variant types may interbreed where their populations overlap. Hybridization may not be indicative of different species. Ex Crossbreeding
Classification Categories Modern taxonomists use the following classification: Species Genus Family Order Class Phylum Kingdom Domain
Classification Categories In most cases, classification categories can be subdivided into additional categories. Superorder Order Suborder Infraorder
Phylogenetic Trees Systematics is the study of the diversity of organisms at all levels of organization. Classification lists the unique characters of each taxon and is ideally designed to reflect phylogeny. Phylogenetic tree is a diagram that indicates common ancestors and lines of descent.
Phylogenetic Trees A primitive character is present in the common ancestor and in all members of a group. A derived character is one that is found only in a particular line of descent.
Tracing Phylogeny Dating and Anatomic Characteristics 1.Fossil Record Fossil record is incomplete; thus, it is often hard to tell to which group a fossil is related.
2.Homology Character similarity stemming from a common ancestor. Homologous structures are related to each other through common descent.
Tracing Phylogeny 3.Convergent Evolution The acquisition of the same or similar characters in distantly related lines of descent.
4.Parallel Evolution The acquisition of the same or similar characters in two or more related lineages without being present in a common ancestor. Molecular Data
Systematics assumes the more closely species are related, the fewer changes there will be in DNA base-pair sequences. Protein Comparisons RNA and DNA Comparisons Molecular Clocks
Classification Systems Until the middle of the twentieth century, biologists recognized only two kingdoms. Plantae (plants) and Animalia (animals) Protista (protists) were added in the 1880s. Whittaker expanded the classification system to five kingdoms in 1969. Added Fungi and Monera.
Three-Domain System
Domain Bacteria and Domain Archaea contain prokaryotic unicellular organisms that reproduce asexually.
Genetically distinguishable by a difference in rRNA base sequences as well as plasma membrane and cell wall chemistry. Archaea live in extreme environments. Methanogens Halophiles Thermoacidophiles
Three-Domain System Domain Eukarya contains unicellular and multicellular organisms whose cells have a membranebound nucleus. Sexual reproduction common. Contains 4 kingdoms.
Protista, Fungi, Plantae and Animalia.