Diversity of Life
BIO 100
Chapter 16
Organization of Life: Organisms are placed into categories based on their evolutionary relationships
8 major catagories:
1. Domain
4. Order
2. Kingdom
5. Family
3. Phylum
6. Genus
4. Class
8. Species
Each order gets increasingly narrow and specific to groups whose common ancestors is increasingly
recently
Each species has a unique 2-part name: Genus & species
Species are Identified by features that reveal:
a.
b.
c.
evolutionary relationships
Anatomy (ex: bone structure)
Molecular similarities (DNA, genotype, genetic traits)
EXAMPLE: the bones of the vertebrate forelimb there are
similarities in the functional anatomy structure
EXAMPLE: the similarities between the pig and chick embryo.
It also appears similar to the human embryo.
Classification of organisms
There are 3 major Domains – this is the largest classification category
1.
2.
3.
Eukarya
Archaea (prokaryotes)
Bacteria (prokaryotes)
** Prokaryotes are single-cell organisms.
The Domain: Archaea
Prokaryotes = the prokaryotes in this category are unicellular organism.
These organisms are simple in structure and have a nucleus with no membrane. They have a complex
metabolic system. They live in aquatic, salty, acidic, or very hot environments or environments that lack
oxygen
Prokaryotes
There are differences that exist among the Prokaryotes. They can live in extreme conditions with variant
temperature:
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Very hot (hot springs) or very cold (Artic)
Exreme high pressures
Below the deep surface of Earth.
Variant pH conditions
Acidic (vinegar) – basic(salty waters) conditions
Domain: Bacteria
These are Unicellular Prokaryotes that lack a membrane bound nucleus.
They are found almost everywhere – in water soil and atmosphere, in the skin, mouth, and intestines
Some cause disease while others are good for the environment
** The Bacteria & Archaea Prokaryotes are similar in appearance under microscope
1. Both are very small, measuring 0.2 to 10 m (micron meters)
2. Both lack organelles: like the nucleus, chloroplasts and mitochondria
3. They differ in structure & biochemical features
4. They differ in plasma membrane composition, ribosome and RNA structures
Domain: Eukarya
The Eukarya domain is subdivided into 4 Kingdoms:
1.
2.
3.
4.
Protista – unicellular or multicellular organisms (protozoans)
Fungi - unicellular or multicellular organisms
Plantae – multicellular
Animalia – multicellular
Eukaryotes either Photosynthesize or absorb/injest food
The Eukarya: Protista
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Most Eukaryotes are single-cell organisms that are either Photosynthetic (photoplankton) or
nonphotosynthetic organisms\
Some are multicellular organisms: Like the seaweed or brown algae
Alveolates: include parasites & predators. Some have flagella and others have celia
The Eukarya: Protista - the Pseudopods include:
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Amoebas (mobile organisms)
Fungi (immobile organisms) that grow rapidly to compensate for the lack of mobility. They
obtain their nutrients from other organisms. They are surrounded by a cell wall (like the plant
cell)
The good, the bad and the ugly side of Fungi:
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Many antibiotics have derive from fungi: like the Penicillins
Yeast ( a fungus) - Makes wine & beer using yeasts
Yeasts makes bread rise
It is Beneficial to the ecology -- by becoming a decomposers of the forest floor
It can produce diseases in humans like:
 Ringworm, athlete’s feet, jock itch
 Candidan albicans: vaginal yeast infections & thrush
Some Protista can produce toxins: like the Aspergillus
The Eukarya: Protista - the Plants
1. Tracheophytes - vascular plants
They have conductive vessels that provide support to the plant. They are seedless plants: like mosses,
horsetails & ferns; and there are seed producing plants that mostly dominate the land
2. Bryophytes – are nonvascular plants
These plants have slow diffusion & distribution of water & nutrients. Examples of these plants include the
liverworts and moss.
3. Gymnosperm – the non-flowering seed plants
4. Angiosperms – flowering seed plants. Flowers attract pollinators. Some plants bare fruits, which
encourage the seed dispersal
The Broad leaves in plants capture more sunlight which increases the production of photosynthesis
The Eukarya: Anemalia
Animal s come in a diversity of forms. They are multicellular & Motile (able to move and migrate). Most of
the animals in this classification lack backbones, however they obtain energy by consuming
other organisms (which is required for cellular respiration)
These species should be able to:
1. Reproduce sexually – there are variable reproductive styles
2. Respond to external stimuli
3. They lack cell walls (which only exist in plant cells)
There are Evolutionary trends among animals.
a.
Invertebrates - lack an endoskeleton of bone or cartilage formation.
All but one animal phylum are invertebrates
b. Vertebrates - have an endoskeleton of bone or cartilage
Sponges & Cnidarians
Sponges: have simple bodies that lack true tissues & organs
Cnidarians: are well armed predators like the Jellyfish, sea anemone, and Hydra
Annelids & Arthropods: Annelids (worms, leeches). These species are:
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Segmentation with repetition of body parts
EIvolved Cephalization (brains) and specialization of body parts
Arthropods – are the most dominant of animals. They have Jointed appendages, specialized for locomotion
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Mollusks (shells)
Chordates
Vertebrates – sea squirt
Invertebretes – bony fish
Evolutionary trends are seen and compared within species. For example the Roundworms –
(Pseudocoelomates).
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It is body is a tube-within-a-tube
I has 2 openings; the mouth and anus
Many forms of these species
o Some are free-living in soil and water, while others are parasitic and live within
a host.
Ascaris - these species move with whip-like motion. Example of these species include intestinal parasites
that are found in many animal species.
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Their eggs enter a host in uncooked vegetables, soil, or feces
The Larvae burrow out of the intestine, and migrate to other organs like the heart, lungs or liver.
Arthropods - Anthropods fall into the Phylum Arthropoda
These are the species with jointed appendages: which allows them to walk, swim, reproduce, eat, and
respond to sensory reception.
The Exoskeleton of Chitin will undergo molting. These have 3 body regions: head, thorax, abdomen. These
organisms have a:
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Well-developed nervous system
Brain and ventral nerve cord
Sense organs - compound eyes, antennae
Arachnids – fall under the Subphylum Chelicerata
These include Spiders, ticks, scorpions, mites
Vertebrates
Birds are classified based on beak and foot types; their Habitat, behavior & how they prey
Reptilia: classified by their ability to produce amniote egg: like the Reptile, turtles, snakes, lizards
Mammals: classified by species that have hair and mammary glands
Vertebrates are Endothermic – having a constant internal temperature; and a placental base.
Examples: Marsupials, mammals, primates