Download Grade 11 University Biology – Unit 1

Grade 11 University Biology – Unit 1
Some Unit Summary Notes
Classifying
 A species is a group of related organisms that can interbreed in nature and successfully produced
fertile offspring.
 There are three species concepts used to classify
 Morphological – based on structure, but “how much is too much” (i.e., How much
difference is needed to define a new species?)
 Biological – based on ability to mate and produce fertile offspring. What happens if
organisms are isolated (e.g., islands) and cannot meet to mate? Are they different?
 Phylogenetic – based on evolutionary history and makes use of DNA …even if organism
is dead
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Bionomial nomenclature – A method to name species
Taxonomy – process of identifying, naming and classifying species. Example below is for Homo
sapiens
Rank
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Taxon
Eukarya
Animalia
Chordata
Mammalia
Primate
Homoinidae
Homo
sapiens
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Three types of evidence are used to classify organisms:
 Anatomical are physical characteristics such as size and shape (e.g., shape of bones of
dinosaurs and birds suggest they are related
 Physiological is the functioning of organisms including the proteins they synthesize (e.g.,
two species may look the same, but if their bodies make different proteins, they are not
related)
 DNA evidence refers to similarities in the genes
Analyzing the relationships among species, you can construct a phylogenetic tree to illustrate the
linkages.
Kingdoms and Domains
 Two cell types classify organisms into three domains: (1) prokaryote (e.g., lacking membranebound nucleus, most are unicellular, no multicellular – rather live in colonies) and (2) eukaryote
(e.g., membrane-bound nucleus, both unicellular and multicellular, larger and more complex than
prokaryote)
Dichotomous Key
 Simple process to choose between only two options (e.g., black hair – Yes or No) to identify
species
Types of Diversity
 Genetic Diversity – Variety of inheritable characteristics within a group including “invisible”
characteristics that an organism carries but does not express
 Species Diversity – Variety and abundance of a species in a given area. This can include
representatives from all six Kingdoms. A measure of a healthy environment is high species
diversity
 Ecosystem Diversity – Variety of ecosystems found on Earth. These can differ in biotic and
abiotic factors, relationships and size. They can be large (e.g., oceans) or very small (e.g., your
mouth, a single plant). This ensures a wide variety of species can live on Earth
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Biodiversity is important for resiliency (e.g., sudden change requires a response. With greater
diversity, some organisms will survive the change. A disease could kill all individuals if they were
the same. With genetic diversity, some may survive and re-establish the population).
Virus and Prions (2.1)
 Viruses are not classified in any Kingdom of living things
 A virus contains genetic material (DNA or RNA) BUT a virus cannot reproduce independently.
Instead, a host is required to make multiple copies of the virus (replication)
 A virus is classified by the shape of its protein covering (capsid)
 A virus enters a host cell. In the lytic cycle, the viral DNA takes over the nucleus and instructs the
host cell to replication the viral particles. When the cell explodes, the viral particles are released
to infect other cells. In a lysogenic cycle, the viral DNA becomes part of the host cell
chromosomes (...at this stage, it forms a provirus). The provirus genetic material is copied as the
host cell undergoes cell division. At some point, the provirus will separate from the host
chromosomes and replicate in a lytic cycle process. As a provirus, the virus can remain dormant
for a long period.
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Prions are pathogenic variants of proteins
They occur naturally in nerve cells, but they cause several degenerative brain diseases
Prokaroytes: Eubacteria and Archaeabacteria (2.2)
 Prokaryotes have two domains: Eubacteria and Archaeabacteria
 Both domains have similar sizes and shapes
being the smallest, simplest living organisms on
Earth. They occur in air, water, soil and on
other organisms.
 The most common shapes are coccus, bacillus
(rod) and spirillium (spirals). Archaea can also
be flat and square
 All species are unicellular BUT they can form
colonies or link to form filaments
 Species in both domains can be aerobic or
anaerobic
 Archaea live in extreme environments (e.g.,
high temperature, high salt concentration).
They are called extremophiles.
 Only Eubacteria cause disease
 Some Eubacteria fix nitrogen, others are
decomposers
 Some Archaea fix atmospheric carbon dioxide, other species live in the intestine of cows
(methanogenic) and release methane gas.
 All species in both domains reproduce asexually by binary fission. The steps are:
 The singular circular chromosome consists only of double-stranded DNA
 The chromosome duplicates
 The two chromosomes attach to the inside of the cell membrane
 The cell elongates
 As the cell membrane lengthens, the chromosomes separate
 The plasma membrane grows inward and a septum (cell wall) forms
 The original cell separates into two smaller, genetically identical cells
Endosymbiosis
 Two prokaryotic cells formed a symbiotic team --- and over millions of years – became one
organism
 A cynobacteria becomes the chloroplasts, the heterotrophic bacteria becomes the mitochondria
and the spiral shaped bactreria forms the flagella
Eukaryote: Life Cycles and Reproduction (2.3)
Asexual Reproduction
 Budding and fragmentation
 This involves mitosis – cell division in which daughter cells receive the exact
chromosome and genetic makeup as a parent cell (i.e., clones)
Sexual Reproduction
 Gametic Life Cycle
 Animals and some brown algae
 Meiosis – a diploid cell (two copies of each chromosome) produces haploid gametes (one
copy of each chromosome). The gametes fuse during fertilization to produce a diploid
zygote. All cell division after that is mitosis. Only haploid cells are gametes (…egg and
sperm)
 Zygotic Life Cycle
 All fungi, some green algae and many protozoans
 Zygote undergoes meiosis
 The only diploid cell is the zygote. All other cells are haploid
 Sporic Life Cycle
 Plants and many algae
 Mitosis occurs in both diploid and haploid phases – called alternation of generations (i.e.,
spore-producing sporophyte generation and gamete-producing gametophyte generation
Kingdom Protista (2.4)
 All eukaryotes except animals, plants and fungi
 Three groups of unicellular protests: (1) protozoans (aquatic, animal-like heterotrophs that ingest
or absorb food), (2) slime moulds and water moulds (fungus-like, heterotrophs) and (3) diatoms,
dinoflagellates and euglenoids (plant-like, autotrophs)
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Protozoans
 Live in water, soil, and living and dead organisms
 Special vacuole for digesting food and removing waste
 Classified by means of movement
 Carcazoans – produce limb-like extensions of cytoplasm (peusdopod) to
move and engulf food
 Ciliates – short, hair-like cilia to swim. Food (bacteria) are swept into an
oral groove in the body, and a vacuole forms to digest the food
 Flagellates – one or more long flagella to swim
 Sporozoans – no movement. Rather, parasites with a life cycle adapted
to transferring offspring to a new host
Fungus-like
 Like fungus – produce spores
 Like protozoan – glide from place to place and ingest food
 Like plants – cell walls with cellulose
 Different types
 Plasmodial slime moulds – similar to protozoans, but produce spores
 Cellular slime moulds – part of life cycle is independent with mitosis cell
division.
 Water moulds – aquatic – appear as fuzzy, white grow on decaying
matter – grow as mass of threads over plant or animal, digest it, and
then, absorb nutrients from the organism – produced reproductive cells
with flagella
Plant-like
 Unicellular, aquatic, chlorophyll-containing BUT do not have leaves, stems, roots or
water-conducting tissues
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Different types
 Diatoms – body with two halves, cell walls contain silica, yellow-brown
choloroplasts to photosynthesize
 Dinoflagellates – live in oceans, protective coats of cellulose plates,
most have two flagella (one is hidden in a grove), Gonyaulax sp. makes
ride tide
 Euglenoids – plant and animal characteristics, chloroplasts, no cell wall,
swim with flagella, eyespot to find light for photosynthesis, also absorb
nutrients across cell membrane.
Algae (3.1)
 Algae are in the Kingdom Protista
 Like plants, algae are autotrophs and store food energy as starch. Algae and plant DNA
sequences are very similar. Yet, algae lack true stems, roots and leaves. As well, algae
are all aquatic because their zygote and embryo are not covered by protective layers.
 Algae have chlorophyll, but it can be different colours (Why? Pigments mask the green
colour of the chlorophyll). Algae are named by the pigment: brown, red or green.
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Brown Algae
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Structurally diverse from simple filaments to long blades
Large brown algae is commonly called sea weed or kelp
Anchored by holdfasts
Blades have air vescicles that keep the blades near the surface of the
water (...and sun energy)
Red Algae
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Green Algae
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Small and delicate
May have filamentous branches
Red pigment allows them to absorb limited sunlight – Thus, able to live at
deep depths
Build up carbonate layers to form reefs
Cause “red tides”
Range from one cell to multicellular organisms
May live on trunks of trees, but most are aquatic
Closely related to green plants because (1) cell wall contains cellulose,
(2) possess similar chlorophyll and (3) store food as starch
Evolution to Land
 Plants are adapted to living on land.
To survive, many evolutionary
adaptations were required
 Vascular bundle to support a
stem, as well as transport
water and minerals (xylem and
phloem). Xylem contain lignin
which is a support material
 Thick cellulose cells and waxy
cuticle to prevent drying out
 Roots to anchor the plant and
allow for uptake of water and
minerals from the ground
 Leaves to perform
photosynthesis and allow for gas exchange).
 Sporic life cycle (i.e., alternation of generations)
 Enclosed embryo to protect it and use of wind to disperse spores or seeds
Kingdom Plantae (3.2)
 Plants have three categories: (1) non-vascular plants, (2) seedless vascular plants and (3) seedproducing vascular plants. The category is based on (1) presence or absence of vascular tissue
and (2) the type of structure (seed or spore) that disperses the species
 A seed is a plant organ that contains an embryo with a food supply covered by a
protective coat. Fertilization (fusion of female and male cells) takes place before the
seed leaves the parent plant
 A spore is a reproductive cell that forms without fertilization and produces a new
organism. Spores do not have stored food, but they are surrounded by a protective coat.
Fertilization takes place after the spore leaves the plant
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Non-vascular plants: Bryophytes
 Includes liverworts and mosses
 Do not have vascular tissues – Thus, they lack true roots, stems and leaves
 Life cycle is alternation of generations. The adult generation (sporophyte) produces
spores while the spore generation (gametophyte) produces sex cells.
Seedless vascular plants
 Ferns
 Have vascular tissue. Xylem transports water and minerals, as well as supports the plant
against the pull of gravity. Phloem transports organic nutrients.
 Ferns produce spores, but like seed-bearing plants, ferns have leaves, stems and roots.
 In the life cycle, the sporophyte is larger and longer lived.
 The sporophyte and the gametophyte are both photosynthetic and capable of survival
and growth independently
Seed vascular plants: Gymnosperms and Angiosperms
 A seed contains a plant embryo and stored food. Within the seed are all the parts needed
to produce a new plant. Seeds contain the next sporophyte generation.
 Two types of spores develop inside the body of the sporophyte: (1) a pollen grain
(reduced gametophyte) produces non-flagellated sperm and (2) the female gametophyte
(located in the ovule) produces the egg
 Gymnosperms
 Conifers
 Developed vascular tissue extending from root, through stem to needle-like
leaves
 Produce uncovered seeds
 Angiosperms
 Flowering plants
 Produce seeds covered by fruits
 Petals of flowers attract pollinators
 Ovary develops into fruit to aid seed dispersal
 Sexual reproduction occurs in the flower
 Monocots (one cotyledon) or dicot (two cotyledons). Cotyledon = seed leaf
inside the seed
Kingdom Fungi (3.3)
 Except yeast, fungi are multicellular eukaryotes that are heterotrophic by absorption (i.e., excrete
digestive enzymes into environment and absorb nutrient molecules through their cell membrane)
 Basic structure is threadlike filaments called hyphae that develop into spores. Hyphae elongate
at their tips and branch to form a filamentous network called mycelium
 Lack chloroplasts
 Cell wall is chitin
 Produce windblown spores during both asexual and sexual reproduction
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Four major Phyla types determined by (1) reproductive strategy and (2) structure of fruiting body
 Chytrids – single-celled, primitive fungi
 Male and female gametes fuse to
make a resting spore
 Asexual reproduction is the
cytoplasm cleaves in a
sporangium to produce motile
zoospores
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Ascomycota - Sac Fungi
 Largest fungal group
 Sexual reproduction produces ascospores within asci (inside fruiting body)
 Asexual produces spores
 Yeasts are unicellular sac fungi that reproduce asexually by budding or mitosis
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Zygospore Fungi
 Sexual reproduction has a zygospore form prior
to mitosis
 Asexual reproduction involves spores forming
within sporangia (see illustration)
Club Fungi (Basidiomycota)
 Sexual reproduction
 Hyphae from two types fuse. Resulting
mycelium has two nuclei and may form
fruiting bodies of mass of hyphae called
basidia. The fruiting body releases spores
called basidiospores (see illustration left)
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Fungi Imperfecti
 Unknown mode of sexual reproduction
 Always reproduce asexually by producing spores
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Lichen
 Symbiotic relationship between fungus and cynobacteria or green algae.
 May be parasitic relationship
Kingdom Animalia (3.4)
 Evolved from Protista
 Over 30 animal Phyla
 All eukaryotes
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Homo sapiens are members of the Chordata Phylum – animals with a notechord (...a flexible, rod
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shaped body found in embryos, and in vertebrates, it becomes the main element of the vertebral column).
Most Chordata have vertebrates and an internal skeleton of bone or cartilage
Heterotrophs
Mobile by means of muscle fibres
Multicellular with specialized cells that form tissues and organs
Live cycle in which adult is a diploid
Reproduce sexually and produce an embryo that undergoes stages of development
Classification of animals is based on the following anatomical features
Anatomical Feature
Variation between Groups
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Cells not organized into tissues
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Cells organized into tissues
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Tissues organized into organs
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Organs organized into system
Number of Body
Layers
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Two cell layers – ectoderm (outside) and endoderm (inside)
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Three cell layers – ectoderm, endoderm and mesoderm
Symmetry
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Asymmetrical – Body shape is irregular
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Radial – Any longitudinal cut through the midpoint yields equal halves
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Bilateral – Only one longitudinal cut through the midpoint yields equal halves
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Sac Plan – Mouth used for intake of nutrient molecules and exit of waste
molecules
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Tube-within-a-Tube Plan – Separate openings (mouth and anus) for food intake
and waste exit
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Acoelomate – Have no coelom (fluid-filled cavity lined with mesoderm that runs
length of the body, absorbs shock, allows organs to exist unattached to body)
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Pseudocoelomate – Have false coelom, coelom incompletely lined with
mesoderm
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Coelomate – Have true coelom
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In protostomes the first (protos) embryonic openings become the mouth (stoma)
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In deuterostomes, the first opening becomes related to the anus and the second
(deuteron) opening becomes the mouth
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No segmentation (no repeating parts)
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Segmentation – Series of repeating parts from anterior to posterior
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Sessile – Adults are not able to move around but animal is motile at some point in
its life
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Motile – Able to more spontaneously and actively
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Asexual
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Sexual
Level of Organization
Body Plan
Body Cavities
Embryonic openings
Segmentation
Movement
Reproduction