Intro to Living Animals Chapter 1 Intro to Living Animals

Properties of Life What is Life? Definition based up properties can be difficult to determine Must look at “life” based on common history of life on Earth.

General properties Unique and complex molecular organization Complex levels of organization Reproduction Genetic “program” or code Metabolism Life Cycle

Complex Molecular Organization Assemble macromolecules Proteins Lipids Carbohydrates Nucleic Acid Chemical composition is same as in non-living matter, however arrangement is unique

Levels of Organization Cells – simplest unit of life Anything below this is not living (ribosome, ER, etc) Tissue – group of cells that perform the same function Organ – group of tissues that perform the same function Organ System – group of organs... Organism – group of organ systems… Life always moves from simple to complex

Organization continued One thing to understand is that certain properties, however, cannot be predicted even with complete knowledge of the components at that level Some properties are influenced by outside source (blood pressure, social interaction) Emergence – the appearance of a new characteristic at a given level Arise from interactions of the components of the system at that level For this reason we must study biology at all levels from cellular processes to population interactions Emergent properties are all products of Evolution – descent with modification.

Reproduction Life does not arise spontaneously ( Miller-Urey experiment), building blocks can…..Hmm?? Goldilocks principle or Anthropic principle? Life has to come from prior life ( book says life arose from non-living matter once) Hmm???? At all levels of the biological hierarchy the pieces are replicated from similar pieces. Genes replicated to produce new genes, animals mate to produce offspring Speciation – process by which a new species evolves. Reproduction is still happening

Reproduction Genetics/Heredity Characteristics of a quality genome Variation to produce traits that span a wide range Scenario 1: A species of shark has no variation in its genome. Its offspring are genetically and physically identical to the parents. How could this be a problem? Think illness, disease, resistance, etc

Genetic code DNA (deoxyribonucleic acid) RNA (ribonucleic acid) Nucleotide arrangements into a double helix (DNA) or a plasmid/ single strand (RNA) Nucleotides: guanine, cytosine, thymine, adenine, uracil Arrangement of nucleotides determines traits and forms a organisms genome The genetic code is similar in all species because much modification throws off protein stability Exception: mitochondria – originally in bacteria, modified to be useful in eukaryotic organisms

Metabolism All living things must maintain nutrients from their environments They break down nutrients to perform chemical process – metabolism Catabolic vs anabolic Metabolism allows for assemblage of proteins, carbs, cellular repair, etc Study of the complexes of these metabolic functions – physiology.

Development All living things pass through a life cycle Unicellular organisms divide into two cells (Think mitosis) Eukaryotic organisms have complex life cycles From (fertilized egg) embryo to infant to juvenile to adult Metamorphosis – butterfly Egg to larvae to pupa to adult

Environmental Interactions All living things interact with their environment Ecology- the study of these interactions Irritability – property of responding to environmental stimuli Most responses are very simple and we do not even realize them

Life Obeys Physical Laws 1st law of Thermodynamics Law of conservation of energy Energy cannot be created, nor destroyed; it can only be converted From a chemistry standpoint however: when a conversion takes place the sum of the reactants only equals the sum of the products when all forms of energy are added up 1kg of “food” does not yield 1kg of “energy” so to say. There are fractional losses in the form of heat, sound, or friction in many cases. 2nd law of Thermodynamics Physical systems tend to move toward entropy (disorder) Ex: Organized molecules of food are broken apart into some form of energy

Zoology as Part of Biology Animalia is one of 6 Kingdoms, along with Eubacter, Archaea, Plantae, Fungi, Protista. Animalia is unique due to the fact all animals are heterotrophic They also lack cell walls and reproduce sexually, for the most part

Principles of Science The Nature of Science What exactly is Science? Zoology is the scientific study of animals, but what makes something scientific? Science is…… Guided by natural laws Is explanatory by reference to natural laws Testable vs observable, known world Its conclusions are tenative and not necessarily final word (Not always 100% true) Falsifiable – can be proven incorrect.

Scientific Method Hypothetical – deductive reasoning It is the way to test things in the sciences Observe Hypothesis Experiment Analyze Conclude

Evolution and Heredity Charles Darwin Predominant theory of evolution Over 140 years old Really is 5 different theories Perpetual change Common descent Multiplication of species Gradualism Natural selection

Perpetual Change Basis of all other theories States that natural world is always changing Organisms undergo change across generations over time Old theory, but was not widely accepted before Darwin

Common Descent States all living things descended from a common ancestor Tree of Life has many branches Separate branches or all one big tree? Studies of genetic material, cell structure, etc supports common descent Phylogeny Basis of animal classification

Multiplication of Species States that evolutionary process creates new species by dividing or transforming older species Very little interbreeding occurs naturally Much debate over the process of speciation

Gradualism States that the large differences in anatomical traits of species arises through a series of many accumulated, smaller, subtle changes Backed up by natural selection Large changes are bad for organisms or species May not explain how all traits formed though

Natural selection Darwin’s most famous theory “Survival of the Fittest” Traits that are most beneficial are passed on and spread throughout populations Negates things like bottlenecking or genetic drift events

Assignment Pg. 19 Questions 5-10

What does all this mean?? Basically Darwin theorized that all species arose from a common ancestor and throughout history environmental pressures, combined with certain traits being favored has caused all the differences in species across the world

Beyond Darwin Darwin’s theory was not just accepted. Constantly reviewed and revised Chromosomal theory of Inheritance Came about after Mendel’s experiments were discovered Neo-Darwinism Modified Darwin’s theories to include the theory of inheritance

Mendelian Genetics Gregor Mendel, Austrian monk, experimented on garden peas Crossed pure-breeding species of peas and recorded results His research was the foundation of modern genetics Dominant/Recessive Trait Expression Formation of Gametes

His experiments did not cover codominance or blended inheritance Punnett Squares His experiments did not cover codominance or blended inheritance Cell Biology Microscopes made it possible to see chromosomes Helped fully establish the chromosomal theory of inheritance

Assignment Pg. 19 Questions 11-13 Due tomorrow