Download Joy of Science

Joy of Science
Experience the evolution of the
Universe, Earth and Life
•  Review of last class
•  Introduction
•  Contents of today’s lecture
•  Quiz time
Unless otherwise noted, all pictures are taken from wikipedia.org
No class on June 3
due to Campus Festival
Review 1
n  The energy for the movement of tectonic plates comes from
A. the Sun
B. outer space
C. the mantle
D. the crust
Review 1
n  The energy for the movement of tectonic plates comes from
A. the Sun
B. outer space
C. the mantle
D. the crust
Review 2
n  A subduction zone is characteristic of
A. a fault zone
B. a transformed plate boundary
C. a divergent plate boundary
D. a convergent plate boundary
Review 2
n  A subduction zone is characteristic of
A. a fault zone
B. a transformed plate boundary
C. a divergent plate boundary
D. a convergent plate boundary
Review 3
n  The subsurface molten material in the mantle that enters a
volcano is called
A. crustal material
B. fault flow
C. magma
d. lava
Review 3
n  The subsurface molten material in the mantle that enters a
volcano is called
A. crustal material
B. fault flow
C. magma
d. lava
Review 4
n  A hot spot in the Earth’s crust is often associated with
A. an oceanic ridge
B. an oceanic trench
C. a fault line
D. a volcano
Review 4
n  A hot spot in the Earth’s crust is often associated with
A. an oceanic ridge
B. an oceanic trench
C. a fault line
D. a volcano
Strategies of Life
All living things have own strategies to obtain
and distribute energy, and then reproduce it
Today’s Keywords
biology, taxonomy, Linnaean classification,
species, kingdoms, domains, Homo sapiens
Let us think about living things on Earth
n  What makes Earth different from all other places we
know in the solar system (perhaps in the galaxy) is
the existence of varied and abundant life
n  Despite the complexity, living things operate
according to the same laws of nature as everything
else we have studied
Ways of thinking about living things
Let’s start thinking about living things with an example – an ant .
An ant can be studied as
n  an individual organism,
n  a collection of specialized organs,
n  a collection of cells,
n  or, we could look deeper inside the cell and its ultimate constituents –
atoms and molecules.
Or, we may be interested in the bigger picture.
n  An ant as part of an ant colony,
n  An ant colony as part of an ecosystem of living and nonliving things,
n  An ecosystem as part of the great global system on the planet.
Each approach complements and is complemented by the others.
What is Life?
- The characteristics of life
1) All living things maintain a high degree of order and complexity
: simplest living thing is more complex than any object constructed by humans.
2) All living things are part of larger systems of matter and energy
: matter recycles in a given system, while energy flows through it.
3) All life depends on chemical reactions that take place in cells
Cells: highly organized chemical building blocks of life
4) All life requires liquid water
: water is an essential medium in the cells
5) Organisms grow and develop
: forms and functions chage at different stages in their lifetime.
6) Living things regulate their use of energy and respond to their environments:
:ex) animal’s hibernation, lowering body temperature by sweat evaporation
7) All living things share the same genetic code passed from parent to offspring by reproduction
: a genetic code is written in the language of the molecule DNA.
8) All living things are descended from a common ancestor
:many similarities among living things arise from their common ancestry.
n  Let’s have time to read through the textbook
for today’s class subject
Introduction
n  Biology: the study of living systems describing the great variety of organisms
on Earth
n  Taxonomy: the grouping of living things (organisms) according to similarities
in structure and their distinctive characteristics
n  Five kingdoms: the broadest classification including 2 groups of single-
celled organisms, fungi, plants, and animals
n  A species: the basic unit of classification, defined to be an interbreeding
population
n  A given species is specialized in groups from most general to most specific.
à phylum à class à order à family à genus à
n  (Linnaean) Classification of Humans
:Animalia à Phylum:Chordata à Class:Mammalia
à Order:Primates à Family:Hominidae à Genus:Homo à
:sapiens
Introduction
n  Biology: the study of living systems describing the great variety of organisms
on Earth
n  Taxonomy: the grouping of living things (organisms) according to similarities
in structure and their distinctive characteristics
n  Five kingdoms: the broadest classification including 2 groups of single-
celled organisms, fungi, plants, and animals
n  A species: the basic unit of classification, defined to be an interbreeding
population
n  A given species is specialized in groups from most general to most specific.
kingdom à phylum à class à order à family à genus à species
n  (Linnaean) Classification of Humans
Kingdom:Animalia à Phylum:Chordata à Class:Mammalia
à Order:Primates à Family:Hominidae à Genus:Homo à Species:sapiens
Cataloging Life
– classifying living things
n  Taxonomy: the scientific process of classifying things and arranging
them into groups
à Classification provides not only a ways of describing our world
but also frameworks to fit new objects and phenomena into them
n  Linnaean classification (by Carolus Linnaeus or Carl von Linné)
: the most successful systematic classification scheme to group all
living things according to their similar characters or differences
à Linnean classification is not only describing species but also
placing them into a hierarchy: a sequence of categories
n  Main categories from broadest to narrowest are,
kingdom, phylum, class, order, family, genus and species
Cataloging Life
– five kingdoms
n  Kingdoms: the broadest classification
Single-celled organisms
1. Monera: Single-celled organisms without a cell nucleus
Ex) bacteria, blue-green bacteria (cyanobacteria)
2. Protista: Mainly single-celled with a cell nucleus and a few multicellular
organisms with simple structure
Ex) amoeba, euglena, some algae
Multicellular organisms with different kinds of interdependent cells,
distinguished primarily by energy obtaining methods
3. Fungi: absorbing materials from their environments
Ex)mushroom, mold, yeast, shelf/bracket fungus
4. Plants: directly from the Sun through photosynthesis
Ex) muticellular algae, mosses, flowering plants, trees
5. Animals: by eating other organisms
Ex) sponge, jellyfish, insect, fish, frog, bird,…, man
A Different Division of Life
- three domains of life
n  From the study of molecular genetics, a dramatically new division of life was
proposed into three distinct domains of life.
1. Single-celled life without nucleus
(all organisms in the Monera kingdom)
* domain Bacteria
* domain Archaea
2. All the other living things: all life based on cells with nuclei
(kingdoms of protista, fungi, plants, and animals)
* domain Eucaryea
è Implies all life in kingdoms of protista, fungi, plants, and animals
are chemically and genetically similar to each other
Simple diagram of 5 kingdoms & 3 domains of life
life
Domain Bacteria
Domain Archaea
Domain Eukaryea
Kingdom Bacteria
Kingdom Archaea
Kingdom Monera
Kingdom Prostista
Kingdom Fungi
Kingdom Plants
Kingdom Animals
Classifying Human Beings
A member of the kingdom of Animals動物界
Phylum chordates脊索動物門: thickened set of nervous down their back
Subphylum vertebrates脊椎動物亜門: backbones
Class mammals哺乳綱: hair, constant body temperature, nursing young
Order primates霊長目: grasping fingers, eyes at front of head, large brain
Family hominidヒト科: primates who walk erect
Genus Homoヒト属: modern humans and closely related with them. All
other species are extinct except Homo sapiens.
Species H. sapiensサピエンス種: only One human species
Race is classification of humans
Different species members in a genus group
n  Example of two different species from a common genus
Polar bear (Ursus maritimus)
Grizzly bear (Ursus horribilis)
* A species is defined to be an interbreeding population, however
hybrids between two different species are occasionally, even in the
wild, possible.
* The hybrids between a polar bear and a grizzly bear are called
pizzly (or prizzly) bear and grolar bear.
Implication of Linnaean Classification
n  Implication from the fact that living things can be grouped in
successive layers so that a kind of family tree can be formed
è all living things perhaps descended from the same primordial
ancestor
èQ: what makes the amount of similarities or difference between
two organisms? A: the amount of time and rate of change
because the two share a common ancestor.
(The chapter of Evolutions of Life)
n  Indeed, each classification group results from real events in the
past when species split off from each other
a common ancestor?
Next class is about,
n  Molecules of Life: p. 252 – p. 258
www.sci.hokudai.ac.jp/~epark/ekpark_e.html