E XAM R EVIEW D IVERSITY OF L IVING T HINGS. B IODIVERSITY number and variety of species and...
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Transcript of E XAM R EVIEW D IVERSITY OF L IVING T HINGS. B IODIVERSITY number and variety of species and...
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