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Brooks Biodiversity Unit 3 Exam
- Plants Architecture: Plant needs i. collection & conversion of solar energy -> leaves ii. positioning & support of leaves -> stems iii. anchorage & absorption -> roots iv. transport -> vascular system
- Leaf Structure: Epidermis, Mesophyll, and Vein (Vascular Bundle)
- Epidermis contains what?: - Cuticle
- Epidermis: outermost cell layer of a plant body cutin: (wax) excreted by epidermis
- Cuticle: Waxy waterproof covering of a plant. Produced by the epidermis and has wax to resist desiccation.
- Guard Cells: Responsible for opening and closing stomata. Works together with stomata to regulate gas
2 / 40 exchange. Prevents movement of water ACROSS surface
- Stomata: Small openings on the underside of a leaf through which oxygen and carbon dioxide can move. Mostly on lower surfaces, sometimes on upper surfaces. Found on both surfaces. Allows for gas exchange.
- 2 aspects of Photosynthesis: light dependent reactions light independent reactions
- Mesophyll contains what?: - Parenchyma
- Dicots have Palisade & Spongy Layers
- Mesophyll: Middle leaf structures photosynthetic layer.
- Parenchyma: Ground tissue that forms the bulk of the mesophyll Can be modified into collenchyma and sclerenchyma Thin and flexible cells Most common and versatile ground tissue Used for metabolic functions and storage of organic products
- Palisade & Spongy layers: Palisade layer: where light dependent reactions occur, near
4 / 40 Spongy mesophyll or spongy parenchyma: soft lower layer. Has access to CO2 through stomata. Kelvin Cycle: where carbon fixation occurs, converting nonorganic CO2 into sugars.
- Vein (Vascular bundle): Transports materials throughout the leaf and contains the xylem and phloem. Separating the VB = damage.
- Stem Structure: Epidermis, Cortex, Collenchyma, Sclerenchyma, Vascular Tissues
- Xylem: (Xylem Up) Distributes water from roots throughout Aimed towards stem Red Tells age of tree Contains: tracheids & vessel members
- Tracheids: Thin, hollow, narrow tube, dead cells with perforated, tapered ends. Vestigial structure First kind of tube made Present in early vascular plants and present in angiosperms and gymnosperms (slow flow)
- Vessel Members: Thick, hollow, wide tube, dead cells with large
5 / 40 holes on end. Clearly visible
- Phloem: (Phloem Down) Distributes the products of photosynthesis (sugary water) to plants tissues. Blue Contains: Sieve tube members (element) & Companion cells
- Sieve Tube Members: hollow, living cells with perforated cells
- Companion Cells: living cells that help keep sieve tube member cells alive. Production of sugars in Kelvin Cycle require transportation done by companion cells into phloem
- Which 4 cell types is most active metabolically when fully functional?: companion cells
- Epidermis in Trees: is replaced by bark or cork. Produced by the cork cambium (tissues that produce other tissues). Cork (dead) = phloem (alive) Cork cambium produces cork. Trees grow wider cause xylem will get clogged
- The cork is produced when?: Secondary phloem
- Composition of Bark: is produced from phloem, cork cambium, or cork.
7 / 40 epidermis Separated by a ring of vascular bundles.
- Ground Tissue System: Includes various cells specialized for functions such as storage, photosynthesis, and support
- Types of Ground Tissue: Parenchyma, Collenchyma, Sclerenchyma
- Collenchyma: celery fibers for support
- Sclerenchyma: hard fibers & nodules responsible for support (ex) rope
- Sclerids: nodules glued together to form shells of nuts.
- Fibers: secretions that reinforce the stem
- Pith: Middle of stem, large because it contains nutrients. Separated by a ring of vascular bundles. Replaced by xylem
- Procambium: Becomes Vascular Cambium Makes xylem inward and phloem outward Grows in rings Gives rise to vascular tissues
8 / 40 Forms advanced tissues
- Monocots: have no cortex
- Germ layers: = stem cells
- Root Structure: i. Epidermis (permeable) with root hairs ii. Cortex iii. Endodermis with Casparian strips iv. Stele v. Apoplastic vs Symplastic pathways
- Stele: Central cylinder with vascular tissues inside.
- Caspian strips: wax, prevents water from growing in between cells
- Used to aid a plant and tell weather in the past: Annual rings
- Apoplastic vs. Symplastic pathway: Water enters through root epidermis and passes in the spaces "between" cortex cells apoplastically until reaching the endodermis. Casparian strips prevent water from passing between endodermal cells. Thus, water is forced through the cell membranes symplastically where it is filtered before reaching the vascular tissues within the stele = osmosis
- Root nodules & Symbiotic bacteria: Bacteria fix nitrogen and are housed in root nodules to supply
10 / 40 Rhizome- underground stem (bermuda grass) Corm- modified stem Tuber- modified underground stem. Gives rise to new growth onion; Potato (however some potatoes are roots) Bulb- modified stem
- Parthenogenesis: development of egg without fertilization
- Propagation: vegetative reproductive. Cut ott a piece of plant ott and it grows.
- Plant Development: '... After germination" Upward growth -Epicotyl or Coleoptile -Phototropism Downward growth Radicle or Hypocotyl Gravitropism
- Positively Phototropic: Growth in response to light
- Structures responsible for downward growth: Radicle and Hypocotyl Contain statoliths (little rocks) that can sense movement in bottom of cell, triggering the plant to grow towards the center of the earth (down)
- Positive Gravitropism: grows in the direction of gravity via statolith sensors
- Meristematic Tissues: Plants version of germ cells
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- Apical Meristems: responsible for increase in plant HEIGHT
- Lateral Meristem: responsible for increase in plant DIAMETER (girth)
- Meristems vs. Germ Cells: A meristem is the tissue in most plants containing unditterentiated cells (meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing. A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. Meristems are in plants and germ cells are in humans but in essence are essentially preforming the same function
- Three Primary Meristems: 1. Protoderm = Epidermis
- Ground Meristem = Parenchyma, Collenchyma, Sclerenchyma = unditterentiated or modified to store pith
- Procambium = VB w/ xylem and phloem
- Exchange & Transport: i. Plants obtain gases, nutrients, minerals, & water via internal fluids ii. Gas exchange begins with the stomata; roots, lenticils iii. Internal transport = xylem & phloem
- Fluid movement in xylem: Adhesion: Attraction of 2 of ditterent things; water molecules bind to cell wall
13 / 40 Water loss in the tropics doesn't matter cause its always raining there. Water evaporation = shade
- Fluid movement in Phloem: Mass Flow: An active transport mechanism Source vs. Sink: Source: Sugars produced by the leaves Sink: Sugars produced by the rest of the plant. Gravity can assist in this downward movement, however getting the sugars into the cells of the Phloem requires energy
- Kingdom Animalia: 1. Multicellular
- Heterotrophs
- Lack Cell Walls
- Two Major Groups of Kingdom Animalia: 1. Invertebrates (no backbone) about 15-30 million
- Vertebrates (chordates with backbones and spinal columns) about 50,000. 30,000 of the 50, are fishes There are animal species that haven't been described yet. 3 million have been described.
- Phylum Cortada: vertebrates, fish, amphibians, mammals, birds, reptiles
- Metazoa: transition from an animal-like protists to multicellular (choanoflagellate) Advantages:
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- Large Size
- Increased Mobility
- Stable Internal Environment (Homeostasis)
- Relative independence from environment
- Radial Symmetry: Diploblastic Can be cut in half anywhere along a central axis No head Little movement
- Bilateral Symmetry: Triploblastic Can be divided down a central line but cannot be cut anywhere Cephalization: concentration of sensory structures in the head (ex) orchids, humans
- Asymmetry: No symmetry Sponges
- Ontogeny: = development "Ontogeny recapitulates phylogeny" Significant similarities among true appearance of vertebrate embryos due to evolution.
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- Secondary Compounds: how plants defend themselves from insects, creating medicine.
- Almost all animals are: arthropods -> insects -> beetles Most abundant and diverse
- Embryology: i. Cleavage patterns: early cell divisions ii. Cell fate
- Radial Cleavage: new cells placed directly beside or on top of previous cells; deuterosome feature
- Spiral Cleavage: new cells placed at juncture between previous cells; protostome feature
- Determinate Cell Fate: fate of cells determined early; separated early cells incapable of developing into entire organism; protostome feature determined @ 4 cell stage
- Indeterminate Cell Fate: fate of cells determined relatively late; separated early cells can develop into entire organism; allows for 'twinning' or genetically identical individuals; deuterosome feature (ex) humans
- Developmental Stages: 1. Morula
- Blastula
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- Gastrulation
- Gastrula
- Germ Layers
- Morula: Solid ball of cells First stage of development in animals
- Blastula: Hollow ball of cells Blastocoel is in the center Second stage of development in animals
- Blastocoel: Chamber (body cavity) of hollow area within a blastula
- Blastocoel is replaced by: mesoderm and coelm
- Gastrulation: Pushing in of cells into the blastocoel Third stage of development in animals
- Byproduct of gastrulation: blastopore
- Gastrula: Develops from gastrulation that creates the cell layers Early multicellular embryo, composed of two or more germinal layers of cells from which the various organs later derive Fourth stage of development in animals
19 / 40 Fossils found on sediments of mountains due to plate tectonics even though they lived in water, during Cambian period
- Parazoans: "Poorly defined tissues"
- Phylum Placozoa: the most primitive metazoan (ex) sponges
- Phylum Porifera: Sponges (can be monoecious or dioecious) Sessile- don't move around Filter water through canal system lined by flagellated collar or choanocyte cells Mostly marine Regenerative characteristics Body filled with spores Poorly defined tissues- Parazoan
- Three body plans:: Asconoid: sac like, simple Syconoid: folded Leuconoid: most complex design
- Outer body layers:: Porocytes:tubular cells which make up the pores of a sponge Myocytes: moving and contracting water, functions like muscle
- Middle layers (mesophyll): Spicules: hard skeletal elements (provide support). Either composed of silicon dioxide or calcium carbonate
20 / 40 Spongin: produces spongy composition, soft, makes up body wall Amoebocytes: give rise to all cells in sponges. Can transform themselves into any other cell in the sponge. All cells can revert back to amoebocytes. Collencytes: neuron-like cells
- Inner layer: Choanocytes: or collar cells, creates current that draws water in for filtration
- Asexual Reproduction: Regeneration Budding (like propagation) Gemmules: packed highly spicule cover of amoebocytes. During unfavorable conditions (rain), activates gemmule to soften up to prevent desiccation and release stem cells. After gemmules have been released, sponge dies.
- Sexual Reproduction: Dioecious: mostly all animals Monoecious: aka hermaphrodite. Almost all animals reproduce in the water.
- Class Calcarea: Spicules made of calcium carbonate.
- Class Hexactinellida: "Glass sponges" Contain 6 rayed spicules made of silica (glass)
- Class Demospongiae: Most common and
