Transcript Exam Review - Diversity of Living Things

EXAM REVIEW
DIVERSITY OF LIVING
THINGS
BIODIVERSITY
number and variety of
species and ecosystems
on Earth

http://www.youtube.com/watch?v=N5ssjM2Fjuc
LEVELS OF BIODIVERSITY
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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

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Binomial nomenclature
Eg: Homo sapiens = humans
 Panthera leo = African lion
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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

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species are named using their genus name
followed by their species name


genus name is capitalized
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Homo
Species name is not capitalized


Homo sapiens
sapiens
both genus and species names are italicized

Homo sapiens
LEVELS OF CLASSIFICATION

7 main levels or taxa (singular taxon)
Humans
Kingdom – Animalia
Phylum – Chordata
Class – Mammalia

kingdom – group of phyla that share similar features
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phylum – group of classes that share similar features

class – group of orders that share similar features

order – group of families that share similar features
Genus – Homo
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family – group of genera that share similar features
Species – Homo sapiens

genus – group of species that share similar features

species – group of organisms that can successfully reproduce
Order – Primates
Family – Hominidae
Mnemonic: King Philip Came Over For Great Spaghetti
SIX-KINGDOM CLASSIFICATION SYSTEM
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There are 6 kingdoms:
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Eubacteria
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Archaebacteria
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Prokaryotes living in harsh habitats; eg: thermophiles
Protista

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Prokaryotes; eg: bacteria
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 complex
membrane-bound nucleus and organelles
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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
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Phylogeny is the history of evolution of a species
or group of organisms
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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
dichotomous
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 occur
https://www.youtube.com/watch?v=wLoslN6d3Ec
http://www.youtube.com/watch?v=Rpj0emEGShQ
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 fission
1. cell grows
2. chromosomes
duplicate
3. cell grows
4. cell divides into two
cells
5. 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 microorganisms 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
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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
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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
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endosymbiosis – relationship in which a singled-celled organisms lives
within another organism
PROTISTS “POTPOURRI OF
THE TREE OF LIFE”
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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
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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
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Euglena
Algae
phytoplankton
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
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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
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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
Have one nucleus per cell
Most are autotrophs
Starch is the main storage molecule
Most have roots
Have cellulose in cell walls
Some reproduce by seed
Fungi
Often have many nucleus per cell
Are heterotrophs
Have few or no storage molecules
Have no roots
Often have chitin in cell walls
None 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, 37
Review Questions:
• Unit 4 Review:
Page 484: #1, 2, 4, 5, 6, 8, 10, 11, 12, 13, 14, 18, 19, 33, 36, 37