Transcript Survey of Life

Survey of Life
Classification
• Taxonomy is a branch of
science that attempts to
organize the many
diverse forms of life
• Linnaean system is most
widely used
• Carolus Linnaeus
1707-1778
How to Remember This
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Dumb (Domain)
Kings (Kingdom)
Play (Phylum)
Chess (Class)
On (Order)
Fine (Family)
Green (Genus)
Sand (Species)
What is a species?
• A group of living organisms consisting of
similar individuals capable of exchanging
genes or interbreeding to produce FERTILE
OFFSPRING
• Genus species
• Homo sapiens, Gorilla gorilla
No
Nucleus
No
Nucleus
Have
Nucleus
The Prokaryotes
• Prokaryotes include the bacteria and archaea.
– Bacteria were discovered in the 17th century by
Leeuwenhoek
– He thought bacteria were generated
spontaneously from inanimate matter
- Around 1850, Pasteur
devised an experiment
showing bacteria present
in air contaminate media,
thus proving the Germ
Hypothesis
Bacteria and Archaea
• Kingdom Bacteria
– Prokaryotic: no organelles
– Often disease causing
• Archaea
– Prokaryotic
– Extremophiles
• Live in weird habitats like hot
springs and super cold
environments
Doman 1: Bacteria
• Prokaryotes (no nucleus)
– DNA concentrated in an area called the nucleoid
– Has nucleolus (where ribosomes are made)
• No membrane-bound organelles
– just ribosomes
• Has cell wall made of peptidoglycan
Prokaryotic Nutrition
• Bacteria differ in their need for, and tolerance of,
oxygen (O2).
– Obligate anaerobes are unable to grow in the presence
of O2; ex. botulism, gas gangrene, and tetanus
– Facultative anaerobes are able to grow in either the
presence or absence of gaseous O2.
– Aerobic organisms (Obligate aerobes) - including
animals and most prokaryotes) require a constant
supply of O2 to carry out cellular respiration.
How Bacteria Obtain Energy
• Every type of nutrition, except for ingestion of
whole food, is found in bacteria.
– Autotrophs – manufacture their own organic
compounds
• Photoautotrophs
• Chemoautotrophs
– Heterotrophs – must obtain their energy by
consuming organic substances produced by
autotrophs.
• Parasites
• Saprophytes (Saprobes)
• Decomposers
Reproduction in Prokaryotes
The Archaea (extremophiles)
• Relationship to Domain
Bacteria and Domain Eukarya
– Archaea are prokaryotes with
molecular characteristics that
distinguish them from bacteria
and eukaryotes.
– Because archaea and some
bacteria are both found in
extreme environments (hot
springs, thermal vents, salt
basins), they may have
diverged from a common
ancestor.
The Archaea
• Types of Archaea
– Methanogens live under anaerobic
environments (e.g., marshes) where they
produce methane.
– Halophiles require high salt concentrations
(e.g., Great Salt Lake).
– Thermoacidophiles live under hot, acidic
environments (e.g., geysers).
6 Kingdoms
Evolution of Protists: Endosymbiosis
Protists are the first eukaryotes. They were formed by prokaryotes “coming
together” and forming a symbiotic relationship.
Proof for endosymbiosis
1. Chloroplasts and mitochondria are the ONLY
organelles in a cell that have their own, circular
DNA
2. Chloroplasts and mitochondria are the ONLY
organelles that have two outer membranes
3. Chloroplasts and mitochondria are the ONLY
organelles that divide by binary fission
Kindom Protista
• Diverse group of
eukaryotic organisms
• Most protists are
unicellular.
• Protist groups are
predominately
organized by feeding
method plus other
unique characteristics.
Kingdom Plantae
• Multicellular eukaryotes with
at least a tissue level of
organization
• Cell wall
• Autotrophic by
photosynthesis; use
chlorophyll a & b
• Store food reserves as starch
• Terrestrial (evolved on land).
Kingdom Fungi
• Multicellular eukaryotes
• Feed as heterotrophs by
absorption
(Saprotrophic)
• Decomposers
(detritovores)
• Body called mycelium
made up of hyphae
• Sexually reproduce via
spores (resist drying
out)
Kingdom Animalia
• All multicellular
• Heterotrophic nutrition by
ingestion
• Diploid adult
• Reproduction is usually
sexual
• Embryonic development
often used to
taxonomically classify
animal groups