A View of Life. Diversity of Life. Defining Life. Chapter 01. Biology NIXON. Chapter 1. Gastricbrooding. frog

Transcription

1 1 Chapter 1 - -Process of Science Diversity of Life Gastricbrooding frog Defining Life

2 2 Defining Life (1) Living things vs. nonliving objects: Comprised of the same chemical elements Obey the same physical and chemical laws So, how do we define life? Several basic characteristics shared by all What makes you different than a rock? Characteristics of Life Organization (Cells) Acquire Materials & Energy (metabolism) Responses to Stimuli (Info) Reproduction Adaptations & Evolution Levels of Biological Organization Uni/Multicellular

3 3 Emergent Properties Biological Organization Emergent Properties: properties that are unique to a level of organization and are due to interactions from previous levels. The whole is more than the sum of its parts! Living Things: Acquire Materials & Energy Energy - the capacity to do work What s the ultimate source of energy???? Metabolism - all the chemical reactions in a cell Homeostasis = the ability to maintain a relatively stable internal environment (regulation) conscious unconscious

4 4 Respond to Stimuli (Info) Living things detect changes in environment Response often involves movement Vulture can detect and find carrion a mile away Tropisms in plants Behavior = how an organism responds to a stimulus Reproduce and Develop Multicellular Organisms: -union of sperm and egg -developmental instructions encoded in genes Evolution: Unifying Concept of Biology

5 5 Evolution Evolution: the change over time of the genetic composition of populations Natural selection: populations of organisms can change over the generations if individuals having certain heritable traits leave more offspring than others (differential reproductive success) Darwin found evidence for NS in Artificial Selection man selectively breeding plants/animals If we can produce such drastic changes in short time by AS, than NS over millions of years. Evolution evidence: The Fossil Record Succession of forms over time Strata of Rock (sedimentary rock) Transitional links Evolution evidence: Biogeography Geographical distribution of species Darwin noticed species on Galapagos resembled species on South American Immigrants more than similar islands

6 6 Evolution evidence: Comparative Anatomy Homologous structures (homology) Similarities in characteristics that results from common ancestry (different functions) Genetic, Developmental, and Structural homology Vestigial structures Fully developed in one group but are reduced in another group. Ex: whale/snake hindlimbs; wings on flightless birds,??humans Pharyngeal pouches, tails as embryos Postanal Tails Evolution evidence: Comparative Embryology Evolution evidence: Biochemical Evidence Darwin??? Similarities in DNA, proteins, genes, and gene products Common genetic code

7 7 Overview of Evolution Evolution is not a directed force! Organisms have differences caused by???? Different traits higher fitness levels Not Progessive Natural Selection doesn t create new traits, just selects those most favorable traits to THAT PARTICULAR ENVIRONMENT. No such thing as higher or lower organism (move away from Aristotle s Scale of Nature) Organize Diversity using Taxonomy: Name and classify living organisms Least inclusive to most inclusive Taxon Categorized by: -morphology -behavior -ecosystem Now: compare genomes Levels of Classification Taxon Human Corn Domain Eukarya Eukarya Kingdom Animalia Plantae Phylum Chordata Anthophyta Class Mammalia Liliopsida Order Primates Commelinales Family Hominidae Poacae Genus Homo Zea Species H. sapiens Z. mays

8 8 The Eukaryotic Kingdoms Scientific Names Binomial nomenclature (two-word names) Universal (avoid common names) Latin-based Genus name is capitalized Species name is lower case Underline if handwritten or italicized if typed Common to abbreviate the genus name Biodiversity: -Abundance of species -Variability of their genes -Different ecosystems in which they live Estimated as high as 15 million (2 million id/named) Extinction is: -death of a species

9 9 Organized process for seeking answers to a problem (question)! 7 Major Steps: 1) Make an observation 2) Identify a problem/question 3) Gather Information/Research 4) Form a hypothesis trial solution/explanation -Reasoning: Inductive (combine isolated facts into larger statement) -Ex. The sun always rises in the east or All organisms are made of cells 5) Experiment to test your hypothesis Reasoning: Deductive -Ex. (premise 1) all organisms are made of cells (premise 2) humans are organisms then humans are composed of cells Set up a controlled experiment that has: 1) Control Group 2) Experimental Group These two groups are identical except for 1 factor! Parts: Independent (experimental) variable Dependent variable (responding)- Constants (controlled variables) parts that are the same within your experimental and control groups Procedure one or more paragraphs 6) Results All data will be here (graphs, charts, etc.) Is the data reliable? Don t analyze data here 2 Types of Data: 7) Draw Conclusions Does it support the hypothesis? Support vs does not support! After collecting data, a scientist may make an inference. Inference=a logical interpretation based on prior knowledge or experience. (Example researcher tests certain parts of a reservoir and infers that all the water is safe to drink). Hypothesis vs. Theory?