Download A View of Life

Biology 1107 - NIXON
Chapter 01
A View of Life
Chapter 1
-A View of Life
-Process of Science
Diversity of Life
• Gastricbrooding
frog
Defining Life
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Biology 1107 - NIXON
Chapter 01
A View of Life
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
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• 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
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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
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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
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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
Evolution evidence: Comparative
Embryology
•Pharyngeal
pouches, ‘tails’
as embryos
•Postanal Tails
Evolution evidence: Biochemical Evidence
Darwin???
•Similarities in DNA, proteins,
genes, and gene products
•Common genetic code
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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
• Species
• Homo
• Zea
• H. sapiens
• Z. mays
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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
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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
7)
Draw Conclusions
Does it support the hypothesis? Support vs does not support!
2 Types of Data:
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?
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