Study Guide Chapter 1 Biology Exploring Life Biology is the scientific study of life Properties of living things Order the complex organization of living things Regulation of internal conditions the ability to maintain an internal environment consistent with life Energy processing acquiring energy and transforming it to a form useful for the organism Growth and development consistent growth and development controlled by DNA Response to the environment an ability to respond to environmental stimuli Reproduction living things reproduce their own kind Evolutionary adaptation acquisition of traits that best suit the organism to its environment Emergent properties With each step upward in this hierarchy new properties emerge that are not present at the level just below it The Biosphere Consists of all the environments on earth that support life An ecosystem Consists of all the organisms living in a particular area and the nonliving environmental components A community All the living organisms in a particular ecosystem make up a community A population Consists of a localized group of individuals of a species An organism An individual living entity A cell is the basic unit of life the structural and functional unit of life Two types of cells Eukaryotic cells Prokaryotic cells contain membrane enclosed organelles including a DNA containing nucleus Plants animals and fungi are eukaryotic Simpler and smaller than eukaryotic cells Lack a nucleus and other organelles Bacteria are prokaryotic Systems biology models the complex interactions of biological systems ranging from the functioning of the biosphere to the complex molecular machinery of a cell Five kingdoms Monera Protista Fungi Plantae and Animalia Domains Domain Eukarya includes Bacteria the most diverse and widespread prokaryotes Archaea like bacteria are prokaryotic and live in extreme conditions Eukarya are eukaryotes Protists protozoans and algae falling into multiple kingdoms The kingdoms Fungi Plantae and Animalia Inductive reasoning to draw general conclusions from many observations Deductive reasoning to come up with ways to test a hypothesis The goal of technology is to apply scientific knowledge for some specific purpose Chapter 14 Defining Species Speciation the process by which one species splits into two or more species The biological species concept defines a species as a group of populations whose members have the potential to interbreed in nature members of a species are similar because they reproduce with each other produce fertile offspring Reproductive isolation prevents members of different species from mating with each other The morphological species concept classifies organisms based on observable physical traits can be applied to asexual organisms and fossils The ecological species concept defines a species by its ecological niche and focuses on unique adaptations to particular roles in a biological community The phylogenetic species concept Reproductive barriers serve to isolate the gene pools of species and prevent interbreeding defines a species as the smallest group of individuals that shares a common ancestor Prezygotic barriers 1 2 3 4 5 In habitat isolation two species live in the same general area but not in the same kind of place In temporal isolation two species breed at different times seasons times of day years In behavioral isolation there is little or no mate recognition between females and males of different species In mechanical isolation female and male sex organs are not compatible In gametic isolation female and male gametes are not compatible 1 2 3 Postzygotic barriers In reduced hybrid viability most hybrid offspring do not develop fully or do not survive In reduced hybrid fertility hybrid offspring are vigorous but cannot produce viable offspring In hybrid breakdown the first generation hybrids are viable and fertile but the offspring of the hybrids are feeble or sterile Allopatric speciation Populations of the same species are geographically separated Sympatric speciation Occurs when a new species arises within the same geographic area as a parent species Gene flow between populations may be reduced by Habitat differentiation or sexual selection Polyploidy for plants Many plant species have evolved by polyploidy in which cells have more than two complete sets of chromosomes Sympatric speciation can result from polyploidy within a species by self fertilization or between two species by hybridization The evolution of many diverse species from a common ancestor is adaptive radiation Hybrid zones Regions in which members of different species meet and mate to produce at least some hybrid offspring Three possible outcomes for hybrid zones Reinforcement strengthening of reproductive barriers ie natural selection Fusion weakening of reproductive barriers Stability continued formation of hybrid individuals Species can evolve rapidly or slowly The punctuated equilibria model draws on the fossil record where species change most as they arise from an ancestral species and then experience relatively little change for the rest of their existence Other species appear to have evolved more gradually Mechanisms of Macroevolution and Phylogeny and the Tree of Life Chapter 15 Macroevolution The major changes recorded in the history of life over long time spans Continental drift mass extinctions adaptive radiation and changes in developmental genes have all contributed to macroevolution Pangaea Formed by plate movement which brought together the land masses Pangea split into northern and southern landmasses called Laurasia and Gondwana Mass extinctions Occur when large numbers of species become extinct throughout Earth due to global environmental changes Causes of mass extinctions enormous volcanic eruptions claimed 96 of marine animal species and took a tremendous toll on terrestrial life a large asteroid that struck the Earth blocking light and disrupting global climate extinguished more than half of all marine species and eliminated many families of terrestrial plants and animals including most of the dinosaurs Consequences of mass extinctions Mass extinctions affect biological diversity profoundly Mass extinctions are random events and can permanently remove species with advantageous features and change the course of evolution forever The fossil record shows that it takes about 5 10 million years or longer in some cases for the diversity of life to return to previous levels The field of evo devo