Chapter 1 - Tri-City

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Transcript Chapter 1 - Tri-City

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
 Complex levels of organization
 Reproduction
 Genetic “program” or code
 Metabolism
 Life Cycle
Complex Molecular Organization
 Assemble
 Lipids
 Carbohydrates
 Nucleic Acid
 Chemical
composition is same as in nonliving matter, however arrangement is
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
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.
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
Characteristics of a quality genome
Variation to produce traits that span a wide
 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,
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
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.
All living things pass through a life cycle
 Unicellular organisms divide into two
cells (Think mitosis)
 Eukaryotic organisms have complex life
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
 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
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
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,
 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
 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
 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
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
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
 May not explain how all traits formed
Natural selection
Darwin’s most famous theory
 “Survival of the Fittest”
 Traits that are most beneficial are
passed on and spread throughout
 Negates things like bottlenecking or
genetic drift events
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
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
Punnett Squares
 His experiments did not cover
codominance or blended inheritance
 Cell Biology
Microscopes made it possible to see
 Helped fully establish the chromosomal
theory of inheritance
Pg. 19
Questions 11-13
Due tomorrow