The Basic Organization of Living Forms

ESC 556 Environmental Biology

Week 2

Fundamentals of LifeCharacteristics of Life

Living matter vs. Inanimate matterCellular organisationNutritionGrowthRespirationResponsivenessMovementExcretionReproduction

Catabolism vs. Anabolism

The Flame of LifeAnalogies

RespireNutritionReproduceExcreteGrowsMovesResponsivenessOrganized

DifferencesDNA/RNAAnabolic Metabolism

The CellSmallest Unit of Life

prokaryotic vs. eukaryotic cellsMembrane bound nucleusOrganelles

Size differencesSurface Area / Volume Ratio

Prokaryotes vs. Eukaryotes

Differences:

Eukaryotes have a nucleus and membrane bound organelles

Genetic material transfer

Cell MembraneSeparate the cell from its environment

Lipid bilayer w/ proteins

Attachment

Movement of water & other bulk items

Transport of molecules & ions

Reception of chemical messages

Passive transportDiffusion, Osmosis, Facilitative diffusion

Active transport (pumps)

EndocytosisPhagocytosis, pinocytosis

Endocytosis

Plant Cell WallsCellulose

Hemicelluloses

Pectin

Lignin

Organic materialHighest in high latititudes

Plant Cell Wall

Energy TransformationsGrowth, maintenance and replication

1st & 2nd Laws of Thermodynamic

Photosynthesis

Enzymes

ATP (Adenine triphosphate)

Photosynthesis & Respiration3 Bya: Capture photons and synthesize organic molecules

2 – 1.5 Bya: Release Oxygen

Respiration

Formula:

6CO2 +12H2O + Light 6O2 + C6H12O6 + 6H2O

Chlorophyll

Chloroplast

Inefficient

Photosynthesis

Enzymes

Materials of Life97 % N, O, C, H

90 & H and O Water

MacromoleculesCarbohydratesLipidsProteinsNucleic Acids

Water ¾ of the earth’s surface

2/3 of all organisms

Three formsPolar molecule

Universal solvent

Adhesion – transport systems

Stable against temperature changes – high heat of vaporization

Most dense @ 4oC

CarbohydratesSmall molecules to long polymers

Energy storage

Sugars (CH2O)n

Short termMonosaccharidesIsomers

Long TermDisaccharides & PolysaccharidesPolysaccharide Glucose

CarbohydratesStructural Elements

Polysaccharide cellulosePolysaccharide chitinCellulases

LipidsNon-polar

Many different kinds

FatsStorage of energy

PhospholipidsCell membranePolar + non-polar groups : Lipid bilayer

Terpenes

Steroids

ProteinsVarious functions

Fibres, enzymes, hormones, transport, ion-binding, toxins

Chain of amino acid subunits (polypeptide)

20 amino acids

Nucleic AcidsInformation storage

Deoxyribonucleic acid (DNA) & Ribonucleic acid (RNA)

DNAReplicate itselfPass on hereditary materialNucleotides

DNA structure

Sugar-phosphate backbone

Four bases

Nucleic AcidsDNA structure

Nucleic Acids/DNA

Nucleic AcidsRNA

Read the DNA & produce proteins

StructureRiboseUracil instead of thymine

From DNA - Proteins

Genetic Code

The Diversity of LifeAt least 10 million species

1.5 million described

Levels of OrganizationIndividual

Unitary vs. Modular

PopulationDefined area

CommunityPhysical feature of the habitat or dominant species

Ecosystem Interaction between communities & their environmentMaterial recycling

Species conceptSpecies

Morphological species conceptidentical by morphological (anatomical) criteria

Biological species conceptgroups of potentially or actually interbreeding natural

populations that are reproductively isolated from other such groups

Isolating mechanismsHabitat, seasonal, behavioral, mechanical, gamete, hybrid

failureProblems with fossil & asexual speciesHybrid problem

Evolutionary/Phylogenetic species conceptAll those individuals that share a common evolutionary history

Phylogenetic relationships

Evolutionary/Phylogenetic species

Classification & the Binomial System

Linnaeus

Felis catus

Ranks

Ranks / Taxonomic Hierarchy

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Eukarya

Animalia

Chordata

Mammalia

Carnivora

Felidae

Felis

catus

Three DomainsBacteria

Archaea

Eukarya

prokaryotes

eukaryotes

Bacteria vs. ArchaeaPeptidoglycan layer

Six KingdomsEubacteria

Archaeabacteria

Animalia

Plantae

Fungi

Protista

prokaryotes

eukaryotes

Six KingdomsEubacteria

Archaeabacteria

Animalia

Plantae

Fungi

Protista

Bacteria

Archaea

Eukarya

ProtistsMulticellularity evolved multiple times

independently

Animalia Blastula

Multicellular heterotrophs

Tripoblasty Ectoderm Endoterm Mesoderm

Movement

Tube-within-tube

Complex nervous systems

PlantaePhotosynthesis

Cell wall

Sessile

350,000 species

Land plants

Land Plants

Nonvascular

Vascular

Gymnosperms

Angiosperms

FungiHeterotrophs

Absorb their food

Cell walls

Spores

Decomposition

Evolution of Kingdoms