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Chapter 1

BIOLOGY 1M03 Chapter Notes - Chapter 1: Cell Membrane, Zygote, Ribosomal Rna

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Jon Stone

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Chapter One- Biology and the Tree of Life
Organisms are ‘alive’
The cell theory involves the idea that all the organisms comprise class
and that all cells derive from pre-existing cells
The theory of evolution by natural selection involves the idea that
species change through time because individuals with particular
heritable traits survive and produce more ospring than do other
A phylogenetic tree is a diagram that may be interpreted as
representing inferred evolutionary relationships among species.
Phylogenies (= ‘tribe sources’) can be established by analyzing
similarities (and dierences) in traits. Species that share distinctive
traits are situated in topological proximity on phylogenetic trees.
Biologists ask questions, generate hypotheses to answer them, and
design experiments or make observations that test the predictions
made by competing hypotheses.
1.1 What does it mean to say that something is alive?
Organisms obtain, comprise of cells, process information, replicate,
evolve as a population
Scienti*c theories comprise of- patterns observed in the natural world
and mechanisms or processes identi*ed that produce the patterns
1.2 The Cell Theory
1660’s Robert Hooke and Anton were *rst people to observe cells
Cell- highly organized compartment bounded by a plasma membrane
that contains concentrated chemicals in an aqueous solution
The complete cell theory states that all organism are made of cells
and all cells come from preexisting cells
oAll cells are descended from a progenitor cells- the zygote
oZygotes are derived from other cells (mainly sperm and eggs)
Hypothesis- proposal
Prediction- something that can be measured and must be correct of
hypothesis is valid
Louis Pasteur- designed an experiment that cells arise from cells and
not by spontaneous generation
Since all cells come from pre-existing cells, all organisms are related
by common ancestry, even multi-cellular organisms
Origin of Life
Idea is that cell-based life emerged from ‘matter’ (i.e., molecules) from
meteors and delivered to earth by meteorites
1.3 The Theory of Evolution by Natural Selection
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