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
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 nonliving 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
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