A Survey of Life

A Survey of LifeA Survey of Life

In this section we will have a quick In this section we will have a quick overview of all the different types overview of all the different types

of living things on Earth.of living things on Earth.

Survey of LifeSurvey 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

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Bacteria

Archea Archaebacteria

Precambrian

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Eubacteria

Plants

Animals

Protista Fungi

Protists

Modern plants

Fungi

Modern animals

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Viruses?

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

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Bacteria

Archea Archaebacteria

Precambrian

cyanobacteria

Eubacteria

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chloroplasts

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 rod-shaped 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 Petroleum recovery• Mining Cleaning oil spills• Waste destruction 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

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Bacteria

Precambrian

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Protista

Algae

Fungal Protists

Protozoa

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Seaweeds

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 hair-like 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 SeaweedsGiant 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.

Plants & most Algae

Animals & most Fungi

Ameobas & Slime molds

Flagellates

Forminarians & Radiolarians

Cryptophytes

Why are mushrooms so popular?

Because they are fun guys!

Fungi

• Fungi (singular fungus) are non-photosynthetic, eukaryotic organisms

• Most fungi have cell walls, and other plant-like 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 disease-causing 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)

• Most fungi are very small – often single celled. These include many disease-causing 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 Many fungi, including the larger ones, produce larger ones, produce colonies composed of colonies composed of strands called hyphae strands called hyphae (singular hypha)(singular hypha)

• A large cluster of hyphae is A large cluster of hyphae is called a mycelium. called a mycelium. Underneath a mushroom you Underneath a mushroom you will find the mycelium… the will find the mycelium… the hyphae from which it grew.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)

Three Types of Plants• Non-vascular plants

– Have no special tissues to conduct water.• Eg. Mosses, liverworts, hornworts

• 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

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Bryophytes

Seeds

Vascular Plants

Angiosperms

GymnospermsCycads, Ginkgos

Conifers

monocots

dicots

Whiskferns, Club mosses

Mosses, liverworts

Horsetails, Ferns

Seed ferns

Algae, seaweed

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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 stalk-like

“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

• Phylum Anthophyta: the “flowering” plants.– Class Monocotyledonae: “monocots”– Class Dicotyledonae: the “dicots”

These are often called the “Gymnosperms”

These are often called the “Angiosperms”

Gymnosperms

Cycads Ginkgo Conifers Welwitschia

Ephedra

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.)

• 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• 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

Seed leaves

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)

View Again

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1. D Dicots have network of veins in leaf2. M Monocots have scattered bundles 3. M Monocots have parallel veins4. M Monocots can have 6 (3x2) flower

petals5. D Dicots have a circle of bundles6. D Dicots can have 5 flower petals7. D Dicots have 2 seed leaves8. D Dicots can have 4 flower petals9. M Monocots have a single seed leaf10. D Dicots have 3 pores in their pollen