No class on June 8 due to Campus Festival

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

June 1, 2012

Contents of today’s lecture

1. Introduction to biology 2. Classifying living things: Taxonomy Five kingdoms Three domains Classification of human beings 3. Survival: Strategies of living things

Terminology

�  Biology: the study of living systems describing the great variety of organisms on Earth

�  Taxonomy: the grouping of living things (organisms) according to similarities in structure and their distinctive characteristics

- Five kingdoms: the broadest classification including 2 groups of single- celled organisms, fungi, plants, and animals - Species: the basic unit of classification, defined to be an interbreeding population �  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

Let us think about living things on Earth

�  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

�  Despite the complexity, living things operate according to the same laws of nature as everything else we have studied

1. introduction

Ways of thinking about living things

Let’s start thinking about living things with an example – an ant . An ant can be studied as �  an individual organism, �  a collection of specialized organs, �  a collection of cells, �  or, we could look deeper inside the cell and its ultimate

constituents – atoms and molecules.

Or, we may be interested in the bigger picture. �  An ant as part of an ant colony, �  An ant colony as part of an ecosystem of living and nonliving things, �  An ecosystem as part of the great global system on the planet.

Each approach complements and is complemented by the others.

1. introduction

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 change 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.

1. introduction

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

1. introduction

What is Life? - The characteristics of life (cont’d)

5) Organisms grow and develop : forms and functions change 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.

1. introduction

Classifying living things

�  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 �  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 �  Main categories from broadest to narrowest are,

kingdom, phylum, class, order, family, genus and species (Kings Play Cards On Fat Green Stools ^_^)

2. Classifying living things

Cataloging Life - Five “kingdoms” �  Kingdoms: the broadest classification

1. Monera: Single-celled organisms without a cell nucleus 2. Protista: Mainly single-celled with a cell nucleus and a few multicellular organisms with simple structure 3. Fungi: absorbing materials from their environments 4. Plants: directly from the Sun through photosynthesis 5. Animals: by eating other organisms

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2. Classifying living things

�  Kingdoms: the broadest classification Single-celled organisms 1. Monera: Single-celled organisms without a cell nucleus 2. Protista: Mainly single-celled with a cell nucleus and a few multicellular organisms with simple structure Multicellular organisms with different kinds of interdependent cells, distinguished primarily by energy obtaining methods 3. Fungi: absorbing materials from their environments 4. Plants: directly from the Sun through photosynthesis 5. Animals: by eating other organisms

2. Classifying living things

Cataloging Life - Five “kingdoms”

�  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

2. Classifying living things

Cataloging Life - Five “kingdoms”

A different division of life -Three “domains” of life

�  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

2. Classifying living things

Simple diagram of 5 kingdoms & 3 domains of life

Life Kingdom Bacteria

Kingdom Archaea

Kingdom Prostista

Kingdom Fungi

Kingdom Plants

Kingdom Animals

Domain Bacteria

Domain Archaea

Domain Eukaryea

Kingdom Monera

2. Classifying living things

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

2. Classifying living things

Different species members in a genus group

�  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.

2. Classifying living things

Implication of Linnaean Classification

�  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 èQ: 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) �  Indeed, each classification group results from real events in the past

when species split off from each other

2. Classifying living things

a common ancestor???

2. Classifying living things

3. Strategies of living things

�  Fungi: a taxonomic kingdom including molds, mushrooms , and yeast, distinct from kingdom plants �  Some are single-celled, but most are multicellular �  Roles of fungi in nature: breaking down dead organic material (most cases), breaking down of rock into soil (lichens) �  Structure of fungi: filaments – thread like stalks – and spore containers on the top of stalks. They absorb material directly. �  Reproductive strategies - By having filaments break off and grow - By producing spores: usually asexual, but also possible by mating two cells in the filaments - Spores can travel long distances through air and water - Lichens, composed of a fungus and a single-celled organism, are often seen as crusty coating on rocks

Strategies of fungi

3. Strategies of living things

�  Plants: Here we define plants only multicellular organisms obtaining energy through photosynthesis and lock it up through chemical reactions in their bodies Two types of plants by the way of reproduction and water circulation �  Simplest plants - Most primitive plants are in the phylum of bryophytes, mosses and liverworts - No roots. Absorb water directly through aboveground structures. - Reproduce both asexually and sexually �  Vascular plants - A phylum of vascular plants - Internal plumbing system consisting of roots, stems, and leaves capable

of carrying fluids from one part to another part of the plant

Strategies of plants

3. Strategies of living things

�  Vascular plants - A phylum of vascular plants - Internal plumbing system consisting of roots, stems, and leaves capable of carrying fluids from one part to another part of the plant è Survive in dry terrestrial environment è Overcome downward pull of gravity - Most primitive ones are ferns: Sperms and eggs generate spores. Main form of plants 300million years ago à Q: Their fates were? - Most common vascular plants are, gymnosperms (produce seeds without flowers) angiosperms (produce seeds with flowers) : Became dominated plant kingdom for last 250 million years.

Seeds (pollen grains) can move long distances via air or by insects

Strategies of plants (cont’d)

3. Strategies of living things

�  Animals: multicellular organisms that must get nourishment by consuming molecules produced by other living things �  A huge variety of species: known over 1.3 millions species �  Respiration of animals is reverse of photosynthesis in plants �  Invertebrates - Most animal species. Without backbones, - Simplest species: between aggregate of cells and true multicellular organisms, such as sponges and corals - Most consist of worms, mollusks, various microscopic organisms - Arthropods (spiders, insects, and crustacea -crabs, lobsters, shrimps) : Hard exoskeleton à ”coat of armor”: shed exoskeletons periodically –molting-

Strategies of animals

CO2 + light + water à O2 + energy (nutrients) : photosynthesis

3. Strategies of living things

�  Vertebrates - With spinal cords in a backbones such as rabbits, birds, frogs, or fish - Weight is supported by internal skeleton and outer coatings are soft - Vertebrate family tree is of transitions from water-dwelling animals to fully landed life Fish (life in water)à Amphibians (a halfway between water and land) à Reptiles (first animal fully adapted to life on land, three-chambered heart and cold-blooded like amphibians (take heat from environment) ) à Birds (thought to be modern descendant of reptiles, four-chambered heart, warm-blooded (constant body temperature)) à Mammals ( females give birth to live young. Exception: platypus (duckbill), living in Australia, lays eggs)

Strategies of animals (cont’d)

Next class is on Molecules of Life: Chapter 15 p. 252 – p. 258 www.sci.hokudai.ac.jp/~epark/ekpark_e.html

No class on June 8 due to Campus Festival