Transcript Survey of Life

A Survey of Life
In this section we will have a quick
overview of all the different types
of living things on Earth.
Survey of Life
•
•
•
•
•
Viruses and Prions (Chapter 25)
Bacteria (Chapter 24)
Protists (Chapter 26 & 27)
Fungi (Chapter 28)
Plants
– Plant terminology (Chapter 29)
– Plant Evolution (Chapter 30)
– Plant Structure and Function (Chapter 31, 32)
• Animals (Next module)
Are Viruses Alive?
• They cause diseases, they have DNA or
RNA but they don’t have all the properties
of life
• In the strictest sense, that means they are
not living things, but…
– They are classified in species (like organisms)
– They are sometimes treated like living things.
• If you are interested in viruses, you can
find much more in chapter 25.
(viruses would make a great research topic)
Geological Timescale
?
Viruses
Archea
Archaebacteria
Eubacteria
First
Cell
Protists
cyanobacteria chloroplasts
Fungi
Precambrian
Jurassic
Triassic
Permian
Carboniferous
Devonian
Paleozoic
2
65
245
Silurian
Precambrian
Modern animals
543
Cambrian
3600 MillionYears Ago
Animals
Mesozoic
Quaternary
Protozoa
Fungi
Ternary
Protista
Ordovician
Bacteria
Modern plants
Cretaceous
Algae
Plants
Ceno
-zoic
Quick overview of viruses
• Viruses consist of a protein
coat, surrounding a core of
DNA or RNA
• They have no organelles, no
cells, no metabolism of their
own.
• Viruses need to “Hijack” a living
cell in order to reproduce or
carry on any metabolic
process.
Virus Shapes
Some Viral Diseases
•
•
•
•
Smallpox (now extinct)
Chickenpox / Shingles
SARS (severe acute respiratory syndrome)
Influenza
“the flu”, “H1N1” etc.
• Acquired Immune Deficiency Syndrome
“HIV” “AIDS”
• The Common Cold
• Poliomyelitis
“Polio”
• Herpes simplex
“cold-sores”, “herpes simplex”
• Rabies
“distemper” or “hydrophobia”
• Hemorrhagic Fever
“Ebola”
Viruses may also play a contributing role in many conditions ranging from warts to cancer
Prions, another tiny pathogen
• Prions are infectious agents in the form of
misfolded proteins.
• Prions work by causing a chain reaction which
twists the normal nerve cell proteins into a
misfolded shape.
• All prion diseases affect the nervous system.
They are untreatable and eventually fatal.
• Diseases caused by prions
• Mad Cow Disease (bovine spongiform encephalopathy: BSE)
• Scrapie (Mad sheep disease)
• Creutzfeldt–Jakob disease (CJD) in humans
Bacteria
• Bacteria are microscopic, prokaryotic
organisms.
– This means that they have no nucleus or
large organelles, although they DO have
loose DNA strands and some ribosomes.
• Bacteria have cell walls, but they are
composed of different materials than the
cell walls of plants.
• There are two main groups of Bacteria:
Archaebacteria and Eubacteria.
Evolution of Bacteria
Archea
Archaebacteria
First
Cell
cyanobacteria chloroplasts
Bacteria
Precambrian
Mesozoic
Quaternary
Ternary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Paleozoic
2
65
245
Ordovician
Precambrian
543
Cambrian
3600 MillionYears Ago
Eubacteria
Ceno
-zoic
Archaebacteria
• Archaebacteria were first discovered in
extreme environments: swamps, salt
lakes, hotsprings, etc.
• Many of them are anaerobic, they don’t
need, and in fact don’t like, free oxygen.
– This makes them similar to some of the
earliest organisms, that evolved before the
earth had an oxygen atmosphere.
Examples of Archeabacteria:
– Methanogens: live in swamps, sewage, and
intestines. Many are anaerobic (don’t like
oxygen) and produce methane gas.
– Halophiles: live in very salty water, like death
valley and the dead sea.
– Thermoacidophiles: live in very hot water,
like hotsprings and hydrothermal vents.
Eubacteria
• Eubacteria are the more familiar bacteria.
Some are beneficial, but many cause
diseases.
• They were originally classified by their
shape
– Bacillus (pl. bacilli) are rod-shaped
– Coccus* are round (eg. streptococcus,
staphlococcus)
– Spirilum & Spirochetes are spiral shaped
*plural Cocci
• In addition, three prefixes can be used to
describe the way they clump together when they
form colonies
– “diplo-” clump in groups of two
– “strepto-” clump in long strings
– “staphlo-” clump together in random clumps.
• So a “staphlobacillus” bacteria would be rodshaped bacteria that join together in random
clumps. A streptococcus would be a round
bacteria that forms long, stringy clumps.
• “strep-throat” is cause by a streptococcus
type of bacteria.
Other Classifications of Bacteria
• Gram Stain reaction:
– Gram-positive bacteria take on the stain
– Gram-negative bacteria don’t
• Cyanobacteria
– Photosynthetic bacteria were once considered
to be algea (former name: blue-green algae)
• Enteric Bacteria
– Live inside digestive tract (eg. E-coli*)
*short for Escheria coli, a naturally occurring bacteria found in our
intestines. Most strains of E-coli are harmless, but a few types are
responsible for food poisoning
Diseases Caused by Bacteria
•
•
•
•
•
•
•
•
•
•
Botulism (rare but serious food poisoning)
Cholera (intestinal disease from bad water)
Dental caries (tooth decay from plaque)
Gonorrhea (an S.T.D.)
Lyme Disease (tick-carried infection)
Rocky Mountain Fever (tick-carried infection)
Salmonella (a common food poisoning)
Strep throat (a throat and respiratory infection)
Tetanus (lock-jaw, a nerve/muscle disease)
Tuberculosis (a lung disease)
Beneficial Bacteria
• Some bacteria are useful for:
– Making dairy products, cheese and yogurt.
– Making vinegar and sauerkraut.
– Helping digest food in our intestines.
– Recycling matter by speeding decay.
– Industrial bacteria have been used in:
• Chemical production
• Mining
• Waste destruction
Petroleum recovery
Cleaning oil spills
Insect control
The Protists
• Kingdom Protista contains:
– single-celled, eukaryotic organisms
– Colonial eukaryotic organisms
– Some multi-cellular eukaryotic organisms, but
only those with minimal tissue differentiation.
• Protists include:
– Protozoa: animal-like protists, mostly single
celled, a few are colonial.
– Algae: plant-like protists, both single-celled and
filamentous (long strings of cells)
– Seaweeds: large, multi-cellular plant-like
organisms with little tissue differentiation.
Geological Timescale
First
Cell
cyanobacteria chloroplasts
Algae
Algae
Seaweeds
Protista
Fungal Protists
Protozoa
Precambrian
Mesozoic
Quaternary
Ternary
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Paleozoic
2
65
245
Ordovician
Precambrian
543
Cambrian
3600 MillionYears Ago
Protozoa
Cretaceous
Bacteria
Ceno
-zoic
Sample Protozoans
• Amoeba: (also spelled ameba)
– A shapeless protozoan with pseudopods
• Paramecium:
– Slipper shaped protozoan with cilia
• Euglena:
– A boat-shaped protozoan with a flagellum
• Volvox:
– A colonial protozoan that looks like a
microscopic soccer ball.
• An amoeba is a
single-celled
organism that
changes shape
constantly.
• It extends
pseudopods to
move.
• It has all the
organelles of
an animal cell,
plus a
contractile
vacuole to help
excrete water
• A paramecium is
a single celled
organism.
• It has tiny hairlike cilia that
beat to help it
move.
• Its motion
pushes food
down its oral
groove into the
gullet
• A paramecium
has a two-part
nucleus. A large
macronucleus
and a smaller
micronucleus.
• A euglena is a
single-celled
organism
• It has a very tough
membrane called a
pellicle.
• It pulls itself
forward using a
flagellum
• Some Euglena
have chloroplasts,
like plants.
• A volvox is a
colonial organism
• It has many cells,
but they are not
connected to make
a proper tissue
• The cells simply
cluster together in
a large, hollow ball,
held together by
strands of
cytoplasm.
Algae
• Algae (singular alga) are small,
photosynthetic protists.
• The best known alga is spirogyra, a pond
scum, but beautiful under a microscope.
• Algae are an important source of oxygen,
but if they grow out of control (or “bloom”)
they will then decay and release toxins
into the water.
Fungal Protists
• A few protists, such as the slime molds,
appear to be related to the fungi.
– Slime molds are strange organisms that
spend part of their lives as single celled
“ameoba”. They then swarm together to form
“network” of slime, that becomes a worm-like
“plasmodium.” The plasmodium crawls along
the ground before sprouting into a colourful
“fungus”
Strange Life of a
Slime Mold
The Seaweeds
Giant protists or simple marine plants?
• Several types of seaweeds are sometimes
classified as protists, and are often
grouped with the algae.
• Examples include:
– Fucus and sargassum (floating seaweeds)
– Giant kelp (huge, tree-sized seaweed)
– Dulse (a red, edible seaweed)
Breaking up the Protista…
• Some biologists feel that the Kingdom Protista has
become a “dumping ground” for anything that is hard
classify as plant, animal or fungus.
• Several proposals have been made to break this
kingdom up into several smaller kingdoms.
Flagellates
Ameobas & Slime molds
Animals & most Fungi
Forminarians & Radiolarians
Cryptophytes
Plants & most Algae
Why are mushrooms
so popular?
Because they
are fun guys!
Fungi
• Fungi (singular fungus) are nonphotosynthetic, eukaryotic organisms
• Most fungi have cell walls, and other plantlike features– but…
• Fungi cannot produce their own food and
must absorb nutrients as saprophytes
(digesting dead tissue) or as parasites
(digesting living tissue)
Small Fungi
• Most fungi are very small – often single
celled. These include many diseasecausing fungi and parasites.
• Examples
– Rust fungus (a wheat and grain parasite)
– Smut fungus (a corn parasite)
– Athlete’s foot fungus (a human parasite)
– Mold and mildew fungi (decay saprophytes)
– Yeast fungi (saprophytes on sugary foods)
Hyphae (fungus colonies)
• Many fungi, including the
larger ones, produce
colonies composed of
strands called hyphae
(singular hypha)
• A large cluster of hyphae is
called a mycelium.
Underneath a mushroom you
will find the mycelium… the
hyphae from which it grew.
Mushrooms
• What we call a mushroom is actually just
the reproductive part of the mushroom
fungus.
• Most of the mushroom consists of the
underground mycelium (or hyphae)
• The above-ground part of the mushroom
produces spores on “gills” underneath the
mushroom cap.
Useful Fungi
• Many fungi are edible:
– Mushrooms (careful! a few are poison! )
– Morels (sponge mushrooms)
– Truffles (the real kind, not the chocolate ones)
• Many are useful for producing things
– Yeasts make alcohol
– Fungi add flavour to blue cheese
• Some fungi produce antibiotics
– Penicillin was first made from a bread mold.
Plants
• Plants are:
– Multicellular
• With differentiated, specialized tissues and cell walls
– Eukaryotic
• Their cells have true nuclei.
– Autotrophic
• Produce their own food by photosynthesis / chlorophyll
In addition, most plants are sessile (they don’t move
around much) and terrestrial (most grow on land)
They range in size from tiny (less than 1cm) to huge
(over 100m)
Non-vascular
Three Types of Plants
• Non-vascular plants
– Have no special tissues to conduct water.
• Eg. Mosses, liverworts, hornworts
Vascular Plants
• Seedless Vascular Plants
– Have special tissues (called xylem & phloem)
to conduct water, but produce spores instead
of seeds.
• Eg, club mosses, horsetails, whiskferns, ferns
• Vascular Seed Plants
– Have xylem and phloem and also produce
true seeds.
• Eg. Cycads, ginkgoes, conifers, flowering plants
Geological Timescale (Plants)
Algae, seaweed
Mosses, liverworts
Bryophytes
Whiskferns, Club mosses
Vascular Plants
First land plants
Horsetails, Ferns
Seed ferns
Seeds
Cycads, Ginkgos
Gymnosperms
Conifers
monocots
Angiosperms
Paleozoic Era
Mesozoic Era
Quaternary
2
Ternary
65
Cretaceous
144
Jurassic
206
Triassic
Permian
290 245
Carboniferous
Period
363
Devonian
409
Silurian
Ordovician
Period
Cambrian
Period
543 510 MYA 439
dicots
Cenozoic
Era
Nonvascular Plants
• Phylum(Division) Bryophyta (true mosses)
– Mosses are found in many environments
– They are small, not more than 5cm tall.
– They have a leafy “gametophyte” and a stalklike “sporophyte above.
• Phylum(Division) Hepatophyta (liverworts)
– Liverworts are similar to mosses, but are
flatter in form
• Phylum(Division) Anthocerophyta
(hornworts)
– Hornworts are similar to liverworts but have
horn-like projections.
Life Cycle of a Moss
• Most of the life of a moss is spent as the
gametophyte, the leafy, haploid bottom
third of the plant shown in the diagram.
• The gametophyte eventually produces
gametes (the moss equivalent of egg &
sperm) that fertilize each other at the
top.
• The fertilized gametes produce the
diploid sporophyte, a stalk that rises
above the moss, and releases spores
• The spores germinate and produce new
gametophytes.
Vascular Plants
Vascular
plants have
special
tissues in
their stems
to conduct
water and
nutrients.
The Seedless Vascular Plants
• Phylum (Division) Psilotophyta
– The “whiskferns”, a primitive, rare and
economically unimportant group
• Phylum (Division) Lycophyta
– The “club mosses”, are larger and tougher
than true mosses. Used as christmas
decorations. Their spores are valuable.
• Phylum (Division) Sphenophyta
– The “horsetails”, a primitive but widespread
group.
• Phylum (Division) Pterophyta
– The ferns, a widespread and ecologically
important group of plants.
A Whiskfern
• Whiskferns are the
descendants of one of the
most ancient vascular
plants.
Club Mosses
• Also called “ground
pine” and “ground
cedar”, several species
of club moss (Genus
Lycopodium) are found
in Canada.
• They are sometimes
used for making
Christmas decorations
• Special effects
technicians use their
highly flammable spores
for fire and explosion
effects
Horsetails
• In the time of the
dinosaurs,
horsetails were
common and grew
the size of trees.
• Now, they are far
less common, and
most are less than
30cm high.
Ferns
• Ferns are widespread.
• Young ferns are
sometimes called
“fiddleheads”
Life Cycle of a Fern
• What we see
of a fern is
only part of
its life cycle
• A completely
different part
is found on
the ground
below the
frond.
The Vascular Seed Plants
• Phylum Cycadophyta: the cycads
• Phylum Ginkgophyta: Ginkgo biloba
• Phylum Coniferophyta: Conifers Pines, spruces,
balsams, cedars, sequoias and other fir trees
• Phylum Gnetophyta: Ephedra and Welwitschia
These are often called the “Gymnosperms”
• Phylum Anthophyta: the “flowering” plants.
– Class Monocotyledonae: “monocots”
– Class Dicotyledonae: the “dicots”
These are often called the “Angiosperms”
Gymnosperms
Ephedra
Cycads
Ginkgo
Conifers
Welwitschia
Gymnosperms
• Gymnosperm means “naked seed”, there
is no ripened ovary or fruit around the
seeds
• The four phyla of gymnosperms produce
their seeds in a “cone” or “strobilus”, NOT
inside a flower that can become a fruit.
Cycad strobilus
Welwitschia strobilus
Pine cone
Angiosperms
• The angiosperms or “flowering plants” are the
most successful group of plants on earth*
• They produce well developed seeds with a
proper seed coat and stored food.
• Angiosperms include all the plants with brightly
coloured flowers, but also include many plants
with dull or hidden flowers, such as:
– Grasses and grains (corn, wheat, barley etc.)
– Most deciduous trees (maples, birches, poplars etc.)
*based on how widespread they are and how many climates they have adapted to.
Types of Angiosperm
Seed leaves
• Monocots
–
–
–
–
Have one “seed-leaf” or cotyledon
Vascular tissue is scattered through stem
Flower petals usually in multiples of 3
Leaves usually have parallel veins
• Dicots
–
–
–
–
Have two “seed-leaves” or cotyledons
Vascular tissue is in rings
Flower petals usually in multiples of 4 or 5
Leaves have a network of veins
Monocot
Dicot
Of course, if a
flower has 12
or 15 petals,
you can’t tell if
it’s a monocot
or dicot
without
checking other
features!
Monocot Dicot Game
• Write the numbers 1 to 10 on a paper
• As the pictures appear, write M or D for
monocot or dicot.
• You will have about 2 seconds per picture.
Monocot or Dicot Game
(click mouse to start)
6
1
2
4
3
8
7
10
9
5
View Again
Answers
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
D
M
M
M
D
D
D
D
M
D
Dicots have network of veins in leaf
Monocots have scattered bundles
Monocots have parallel veins
Monocots can have 6 (3x2) flower petals
Dicots have a circle of bundles
Dicots can have 5 flower petals
Dicots have 2 seed leaves
Dicots can have 4 flower petals
Monocots have a single seed leaf
Dicots have 3 pores in their pollen