EXAM REVIEW

DIVERSITY OF LIVING THINGS

BIODIVERSITY

number and variety of species and ecosystems on Earthhttp://www.youtube.com/watch?v=N5ssjM2Fjuc

LEVELS OF BIODIVERSITY

Genetic Diversity

The sum of all the different forms of genes present in a particular species (eg: variety of genes in grey squirrels)

Allow populations to adapt to changes in environmental conditions and evolve over time

Helps ensure the survival of a species

Human activity that decreases genetic diversity Artificial selection in agricultural crops

Lack biodiversity and are vulnerable to disease

LEVELS OF BIODIVERSITY

Species Diversity Refers to the variety of species and relative

abundance of the species in a given area Allows ecosystems to survive environmental changes

(eg. Drought, plagues, disease)

Each species has a certain set of conditions in which it can survive

Each species contributes to the whole ecosystem

LEVELS OF BIODIVERSITY

Ecosystem Diversity Refers to a diverse range of habitats, the various

organisms that live in the habitats, and the relationships that connect them

Refers to large scale ecosystems as well as small, microscopic ecosystems

All living things in an ecosystem are interconnected; changes to a single part will have some effect on the entire ecosystem and its biodiversity

CARL LINNAEUS

1707-1778 Swedish scientist “father” of taxonomy classified organisms

based on their physical similarities

established the current binary naming system used to name species Binomial nomenclature

Eg: Homo sapiens = humans

Panthera leo = African lion

BINOMIAL NOMENCLATURE formal naming system developed by Linnaeus Each organism is assigned a 2 part scientific name using

Latin words (sometimes Greek) Provides a common language for all scientists

species are named using their genus name followed by their species name Homo sapiens

genus name is capitalized Homo

Species name is not capitalized sapiens

both genus and species names are italicized Homo sapiens

LEVELS OF CLASSIFICATION

7 main levels or taxa (singular taxon)

kingdom – group of phyla that share similar features phylum – group of classes that share similar features class – group of orders that share similar features order – group of families that share similar features family – group of genera that share similar features genus – group of species that share similar features species – group of organisms that can successfully reproduce

Mnemonic: King Philip Came Over For Great Spaghetti

Humans

Kingdom – Animalia

Phylum – Chordata

Class – Mammalia

Order – Primates

Family – Hominidae

Genus – Homo

Species – Homo

sapiens

SIX-KINGDOM CLASSIFICATION SYSTEM

There are 6 kingdoms:

Eubacteria Prokaryotes; eg: bacteria

Archaebacteria Prokaryotes living in harsh habitats; eg: thermophiles

Protista Single or multicellular; some eukaryotes; eg. Algae

Fungi Multicellular, heterotrophs; eg: mushrooms, yeast

Plantae Animalia

THREE DOMAINS

Today, many biologists call the broadest taxon a domain

There are 3 domains: Bacteria – prokaryotic cells Archaea – prokaryotic cells Eukarya – eukaryotic cells

Prokaryotes: no true nucleus, mitochondria or chloroplasts

Eukaryotes: more complexmembrane-bound nucleus and organelles

MODERN CLASSIFICATION

Linnaeus grouped species according to their morphology (structure and function)

Biologist now use several types of evidence to help classify organisms including evolutionary relationships Fossil records, historical geographical range, protein

and DNA similarities, etc. Based on the belief that organisms change over time

Phylogeny is the history of evolution of a species or group of organisms Phylogenetic trees (cladograms) are used to show

these evolutionary relationships

DICHOTOMOUS KEYS

A series of paired statements that lead to the identification of an organisms

Used to help identify an unfamiliar organism

Activity 9.1.1 – Using a Classification Key Page 332- Complete the activity with a partner - Complete all questions; (e) is optional

Homework: p. 334 #1, 2, 5, 6

DICHOTOMOUS KEYS – MORE PRACTICE

Create a dichotomo

us key using the following

footprints.

Taxonomy Review • The 6 kingdoms are divided among 3 domains based

on general cell structure• Bacteria: Eubacteria (prokaryotic cells)• Archaea: Archaebacteria (prokaryotic cells)• Eukarya: Protists, Fungi, Plants, Animals (eukaryotic cells)

• What is the difference between prokaryotic and eukaryotic cells?– Prokaryotic: no true nucleus – Eukaryotic: true, membrane-bound nucleus

Where do viruses fit in the ‘Tree of Life’?• They do not fit in the 6 kingdom system of classification.

They occupy a position between living and non-living matter

• Non-living characteristics:– Outside of a living cell, a virus is lifeless chemical and

carries out no life function on its own – they are not made of cells– cannot reproduce on their own

• Living characteristics:– Can reproduce once inside a living cell– Store genetic info – Can adapt to their environment through genetic

mutation

• Virus is the Latin word for poison• Not discovered until 1934 using an early electron microscope• Very small: 5000 influenza viruses fit on the head of a pin

Virus Structure • Nucleic acid core – DNA or RNA• Capsid – protective protein coat

surrounding genetic material; various geometric shapes

Bacteriophages (phages) are viruses that invade bacteria and contain:

• Head – capsid • Tail – sheath, plug and tail fibers

– Used to inject genetic material into the host cell

Viral Replication• Replication – how genetic material is

duplicated before a cell divides

Lytic Cycle

1. Attachment- virus chemically recognizes host cell and attaches- whole virus, or its DNA, enters the cell’s cytoplasm

2. Synthesis - host cell replicates virus components (DNA, protein, etc.)

3. Assembly- new virus particles are assembled

4. Release - new viruses are released from infected cell, host cell dies

Viral Replication – Lytic vs Lysogenic Cycle

Viral Replication – Lytic vs Lysogenic Cycle

• Lytic Cycle– Viral DNA causes destruction of host

DNA– Virus DNA takes over the host cell and

replicates 20-500 new viruses – Viruses are transmitted during the lytic

cycle

• Lysogenic Cycle– Virus does not kill the host cell outright – Virus co-exists by integrating into the

bacterium’s DNA – Virus DNA is replicated along with the

host DNA for many generations – Host cell may be unaware and

unaffected – Damage or stimulus can trigger the lytic

cycle to occurhttp://www.youtube.com/watch?v=Rpj0emEGShQhttps://www.youtube.com/watch?v=wLoslN6d3Ec

Vaccines

• substances that contain weakened forms or parts of a dangerous virus

• do not cause viral diseases

• used by humans to cause immune system to create antibodies that will kill dangerous viruses when exposed to active viruses

http://www.youtube.com/watch?v=abBpWqFV7kw

Uses of Viruses• creating vaccines• delivering drugs to

target cells• gene therapy

– inserting a missing gene into a person’s DNA

– creating genetically modified organisms

Viral Vectors and Gene Therapy

• Gene therapy uses viruses as vectors (carriers) to carry specifically altered DNA into cells

• Scientists must remove the virus DNA, replace it with the desired DNA and allow the virus to mix with and enter desired cells

• Studies have shown that gene technology has a very low risk of causing problems

https://www.youtube.com/watch?v=bLI1Gfb0ynw

Archaebacteria• “Archaea” = Ancient • Believed to be the first species on

Earth• Most are anaerobic – live without

oxygen• Well-suited to extreme

environments– Acidophiles – live at pH <3– Thermophiles – live at very high

temp (>100°C)– Halophiles – live in areas with high salt

Archaea and Eubacteria• All bacteria share a number of

common characteristics:– All prokaryotic– All single-celled– All have a single chromosome– All reproduce asexually through

binary fission• Primary difference between

kingdoms is related to presence or absence of peptidoglycan in cell wall – Present = Eubacteria – Absence = Archaea

Eubacteria – Structure• made of prokaryotic cells that include the following structures:

• Capsule• sticky outer coating that prevents water loss, resists high temperatures and

controls entry to cells (only found in some bacteria)

• Cell wall• made of peptidoglycan

• Cell membrane• DNA

• large single chromosome• plasmid – small loop of DNA

• Ribosomes• Pilli

• cytoskeleton projections • on the outside of cell• allow for conjugation

• Flagellum• cytoskeleton projections on the outside of cell; allow for movement

Eubacteria - Structures• Shapes, size and arrangement are variable• Three common shapes include:

– Coccus = round shape– Bacillus = rod shape– Spirillum = spiral shape

• Common arrangements include:– Spirilla – found singly – Diplo arrangement

• bacteria that exist in pairs– Staphylo arrangement

• bacteria that exist in clumps– Strepto arrangement

• bacteria that exists in chains

What would you call these?

Streptococci – strep throat and pneumonia

Spirillum – cholera and syphilis

Diplobacilli

Streptobacilli – Rat-bite fever

Staphylococci – food poisoning and flesh-eating disease

Eubacteria – Reproduction • reproduce asexually

using binary fission1. cell grows2. chromosomes

duplicate3. cell grows4. cell divides into two

cells5. daughter cells have

the same genetic makeup as the parent cell

Eubacteria – Reproduction

• Eubacteria are able to exchange DNA or acquire new DNA from their environment to increase genetic diversity

• Conjugation– two eubacteria attach using

their pilli– a copy of a plasmid passes

from one eubacteria to another

https://www.youtube.com/watch?v=VU7brO7A36w

Antibiotics• substances that kills or weaken micro-organisms

– natural – produced by bacteria or fungi– synthetic – manufactured by humans

• used in nature by bacteria and fungi to kill other micro-organisms they compete with for resources

• used by humans to kill bacteria that cause infection and disease

http://www.youtube.com/watch?v=-iE-JbtxB6w

Antibiotic Resistance

• occurs when a population of bacteria can no longer be killed by an antibiotic

• occurs overtime when antibiotics cannot kill all bacteria in a population

• resistant bacteria continue to divide and make up more of the population

• bacteria population evolve to be unaffected by the antibiotic

EUKARYOTIC EVOLUTION – REVIEW

evidence suggests that eukaryotic cells evolved from prokaryotic cells mitochondria and chloroplasts have two membranes inner membrane is similar in composition to

prokaryotic cells outer membrane is similar in composition to

eukaryotic cells mitochondria and chloroplasts have their own genetic

information genetic information is in the form of a chromosomes

similar to prokaryotic chromosomes mitochondria and chloroplasts reproduce within the

cell using binary fission

EUKARYOTIC EVOLUTION - ENDOSYMBIOSIS

evidence suggests that eukaryotic cells evolved when ancestral eukaryotic cells (with a membrane bound nucleus) engulfed prokaryotic cells and established an endosymbiotic relationship with them endosymbiosis – relationship in which a singled-celled organisms

lives within another organism

PROTISTS “POTPOURRI OF THE TREE OF LIFE”

Protists are essentially any eukaryote that does not fit into plant, animals, or fungus Lack at least one characteristic that would allow them to belong to another

kingdom

It is believed that all other eukaryotes evolved from protists Plant-like: Autotrophic, perform

photosynthesis, some have cell walls

Animal-like: Heterotrophic, motile Fungi-like: heterotrophic, cell walls

made of cellulose (not chitin)

PROTISTS – STRUCTURE made up of eukaryotic cells dramatic range in size from unicellular to multicellular (most unicellular) Lack specialized tissues and organs Most are motile (use cilia, pseudopods (projections), or flagella to move

around) Most found in water Asexual or sexual reproduction Autotrophs, heterotrophs, or

parasites

https://www.youtube.com/watch?v=UOfY26qdbU0

PLANT-LIKE PROTISTS

Autotrophs (can produce own food through photosynthesis)

Contain chlorophyll; photosynthetic Traditionally called algae; today algae refers to any

photosynthetic organism without tissues Many species (ie. Algae, phytoplankton) are important

primary food producers in food chains and supply 67% of the global supply of oxygen through photosynthesis

phytoplanktonAlgae Euglena

ANIMAL-LIKE PROTISTS

Also known as Protozoa All are heterotrophs (cannot make own food) Must move to obtain their food; classified

based on type of locomotion Also classified based on types of organelles, life

cycle, mode of reproduction, nutrition, etc. Live in a diverse range of moist habitats Reproduction is usually asexual – binary

fission

Ameoba Chaos chaos

Giardia lamblia stomach parasite

Paramecium

https://www.youtube.com/watch?v=pvOz4V699gk amoeba eats 2 paramecium

FUNGI-LIKE PROTISTS

Referred to as slime moulds Heterotrophs Prefer cool, shady, moist places and are found

under fallen leaves or rotting logs At some stage of life they resemble animal-like

protists and have flagella; other times they produce spores like fungi do

Do not always remain single-celled – becoming multicellular is considered a big advancement

Diversity of Fungi• Examples: moulds, mildew, yeast,

truffles, and crop rusts• General Characteristics:

– Eukaryotic– Usually multicellular– Cell walls made of chitin– Heterotrophic: Many look like

plants but can’t make their own food– Don’t ingest their food

• They release enzymes into their environment that break large molecules into smaller molecules that they can absorb

Use of Fungi• Important decomposers that

help to cycle carbon and nitrogen

• Return nutrients to soil for use by plants

• Obtain nutrients by feeding on dead organisms

• Other fungi are parasites and obtain nutrients from living organisms causing damage to the host

https://www.youtube.com/watch?v=GvD-8ZfxfOY – how yeast makes bread

Structure of Fungi• Fungus are made of long threads called hyphae• Two main parts of fungus:

– Fruiting body (above ground) – reproductive structure– Mycelium (below ground) – interwoven mat of hyphae

Fungi vs Plants • Similarities:

– eukaryotic cells– Numerous organelles– Have cell walls – Most anchored in soil or other substrate– Reproduction can be asexual, sexual, or both– Stationary

• Differences: Plants Fungi

Have one nucleus per cellMost are autotrophsStarch is the main storage moleculeMost have roots Have cellulose in cell wallsSome reproduce by seed

Often have many nucleus per cellAre heterotrophsHave few or no storage moleculesHave no roots Often have chitin in cell wallsNone reproduce by seed

Plant & Animal Kingdoms

• Refer to Google Docs created on the Chromebooks

Diversity Exam Review Topics:•Biodiversity – human impacts•Classification systems – levels of taxonomy, nomenclature•Viruses •Bacteria •Protists – basic characteristics •Fungi – basic characteristics•Plants – basic characteristics •Animals – basic characteristics •Create a dichotomous key – practice p. 486 #36, 37Review Questions:•Unit 4 Review:Page 484: #1, 2, 4, 5, 6, 8, 10, 11, 12, 13, 14, 18, 19, 33, 36, 37