Classifying Nature
(Chapter 6)
Living Things are Alike
• Common Characteristics like:
• Cells
• Tissues
• Organs
Our Study of Life
• How do our bodies work?– Physiology
• What is our place in Nature?– Ecology
• Our Bodies, like Life, are Organized!
ƒ1-2 Chapter 1 4
OH H
CH2OH
Levels ofBiological Organization I
SubatomicSubatomic ElectronElectronNeutronNeutronProtonProton
NitrogenNitrogenCarbonCarbonHydrogenHydrogen OxygenOxygen
DNADNAGlucoseGlucoseWaterWater
NucleusNucleusChloroplastChloroplastMitochondrionMitochondrion
Nerve CellNerve Cell
AtomicAtomic
MolecularMolecular
OrganelleOrganelle
CellularCellular
ƒ1-2 Chapter 1 5
Levels ofBiological Organization II
TissueTissue NervousNervousTissueTissue
BrainBrain
NervousNervousSystemSystem
PronghornPronghornAntelopeAntelope
OrganOrgan
Organ SystemOrgan System
OrganismalOrganismal
ƒ1-2 Chapter 1 6
Levels ofBiological Organization
III
PopulationPopulationHerd of PronghornsHerd of Pronghorns
HawkHawk
WaterWater
Earth’sEarth’ssurfacesurface
CommunityCommunity
EcosystemEcosystem
BiosphereBiosphere
PronghornsPronghorns
HawkHawk GrassGrass
PronghornsPronghornsSnakeSnakeBushesBushes
SoilSoilAirAir
SnakeSnake
How do we fit in?
• Where do we fit in the classification of all organisms?
• What is a classification?
• Why be classified?
• We are in the Kingdom Animalia and are Mammals!
Figure 6,1How do we fit in?
Animalia – development by means of an embryonic stageNo cell walls. Do not undergo photosynthesis
Plantae – contain a cell wall carry out photosynthesisNon-motile life stages.
Fungi - contain cell wallDo NOT photosynthesize
Protista – No cell walls reproduce by spores – motile
Monera – the bacteria: single-cell organisms
There are two major types of cells
1. Prokaryotic
2. Eukaryotic
• The eukaryotic cell is more complex and contains organelles
• The DNA of a eukaryotic cell is contained in the nucleus
Nucleus(contains
DNA) Eukaryotic cell
Prokaryotic cell
DNA(no nucleus)
Organelles
Figure 6.2Biological Evolution• First true cells were prokaryotic.
– Eukaryotic cells evolved later, followed by the other kingdoms.
Biological evolution is a change in life forms that has taken place in the past and will take place in the future.
Adaptation is a characteristic that makes an organism able to survive and reproduce in an environment.
Box 6.2 (1)
Box 6.2 (2)
Components of a Cell
Components of a Cell• Nucleus--contained within a cell by nuclear
envelope. The nucleus contains DNA.• Ribosomes--these structures make protein.• Endoplasmic Reticulum--this is a membrane
network composed RER--rough has ribosomes makes proteins, and SER--smooth makes lipids.
• Golgi Apparatus--modifies proteins involved in secretion.
• Endomembrane system--Composed of nuclear envelope, ER, Golgi, Lysosomes and Vesicles, these organelles all work together to make protein sorting and protein secretion possible.
Mitochondria are not partof the endomembrane
system • Contains its own genetic material
• Has 37 genes
• Directly passed on by your mother
• Does not change
Components of a Cell
• Mitochondria make most of our ATP!• Mitochondria have a double membrane--this
is required for ATP production.• Mitochondria have highly folded inner
membrane called cristae--this is where ATP is made.
• Mitochondria perform cellular respiration--literally cell breathing. Oxygen is used and CO2 is made. ATP is the end result.
• Fermentation occurs when there is no oxygen.
The Mitochondria • Contain their own DNA and
protein-synthesizing machinery
– Ribosomes, transfer RNAs, nucleotides.
– Thought to have evolved from endosymbiotic bacteria.
– Divide by fusion
– The DNA is in the form of circular chromosomes, like bacteria
– DNA replication is independent from DNA replication in the nucleus
The MitochondriaSite of Cellular Respiration
• This process requires oxygen.• Composed of three stages:
– Glycolysis--glucose splitting, occurs in the cell. Glucose is converted to Pyruvate.
– Krebs cycle--Electrons are removed--carriers are charged and CO2 is produced. This occurs in the mitochondrion.
– Electron transport--electrons are transferred to oxygen. This produces H2O and ATP. Occurs in the mito.
Box 6.2 (3)
The Chloroplast• Contain their own DNA and
protein-synthesizing machinery
– Ribosomes, transfer RNAs, nucleotides.
– Thought to have evolved from endosymbiotic bacteria.
– Divide by fusion
– The DNA is in the form of circular chromosomes, like bacteria
– DNA replication is independent from DNA replication in the nucleus
The Chloroplast• Membranes contain chlophyll
and it’s associated proteins
– Site of photosynthesis
• Have inner & outer membranes
• 3rd membrane system– Thylakoids
• Stack of Thylakoids = Granum
• Surrounded by Stroma– Works like mitochondria
• During photosynthesis, ATP from stroma provide the energy for the production of sugar molecules
The Plant Golgi Network
The Plant Cell wall• Cell walls are held together
by the middle Lamella.
• Made up of:
• Cellulose
• Xyloglucan
• Pectin
• Proteins
• Ca ions
• Lignin
• other ions
• Water
The Plant Cell wall• The plant cell wall is a layer of
structural material external to the protoplast, built from polysaccharides and proteins.
• The wall contains components for signaling and communication by symplastic continuity through plasmodesmata and maintains molecular connections with the plasma membrane and cytoskeleton
The Plant Cell wall• The cell wall is the organelle that
ultimately controls the shape of plant cells and consequently of organs and whole organisms.
• It is sometimes naturally strengthened and made considerably more resistant to such abuses as pathogen infection by the release of specific oligosaccharides and enzymes and by overlaying or impregnation with cutin, suberin, waxes or silica
Summary• Classification is based on similarities and
evolutionary history
• Prokaryotic cells – Have no organelles– No nucleus – one single chromosome
• Eukaryotic cells– Many organelles– Large complex genome containing many chromosomes
Summary – and thoughts for the next few weeks
• Biological evolution continues at act today in all species
• Natural selection continues to act today by both differential mortality and differential reproduction
• One frequent result of evolution within species is geographic variation
The end
Any Questions?