Biodiversity unit 3

Plants Architecture

Understanding the needs of plants including solar energy collection, leaf positioning, and water uptake.

Key components for solar energy collection in plants

Leaves are essential for collection and conversion of solar energy.

Positioning & support of leaves

Performed by stems in plant architecture.

Anchorage & absorption in plants

Roots provide anchorage and absorb water and nutrients.

Transport in plants

Managed by the vascular system.

Leaf Structure

Main components include epidermis, mesophyll, and vascular bundle.

Epidermis contains what components?

Cuticle and guard cells with stomata.

Cuticle definition

A waxy water-proof covering produced by the epidermis to resist desiccation.

Guard Cells role

Open and close stomata to regulate gas exchange.

Stomata function

Small openings for gas exchange, mostly located on the lower surfaces of leaves.

Two aspects of photosynthesis

Light-dependent reactions and light-independent reactions.

Mesophyll function

Photosynthetic layer in leaves; contains parenchyma.

Parenchyma definition

Ground tissue forming the bulk of mesophyll, versatile for metabolic functions.

Palisade layer significance

Where light-dependent reactions occur in dicot plants.

Spongy mesophyll

Lower layer of mesophyll allowing CO2 access through stomata.

Kelvin Cycle purpose

Where carbon fixation occurs, converting inorganic CO2 into sugars.

Vein (vascular bundle) role

Transports materials throughout the leaf, containing xylem and phloem.

Xylem function

Distributes water from roots throughout the plant.

Tracheids characteristics

Thin, hollow, narrow tubes; dead cells with tapered ends.

Vessel Members characteristics

Thick, hollow tubes; dead cells with large holes on the ends.

Phloem function

Distributes photosynthetic products (sugary water) to plant tissues.

Sieve Tube Members description

Hollow, living cells that facilitate sugar transportation.

Companion Cells role

Support sieve tube members and help in sugar production.

Importance of cork cambium

Produces cork, which replaces the epidermis in trees.

Bark composition

Produced from phloem, cork cambium, and cork.

Lenticels definition

Cracks in the bark that facilitate gas exchange.

Secondary Growth process

Increases plant girth through vascular and cork cambium activity.

Wood composition

Produced by xylem, forming annual growth rings.

Heartwood characteristics

Clogged xylem located deeper into the trunk, offering little water transport.

Sapwood function

Newer xylem that allows free flowing water transport.

Effect of girdling plants

Cutting a horizontal band can damage vascular cambium and is fatal.

Cortex description

Yellow layer inside the epidermis, has various functions.

Ground Tissue System inclusions

Includes parenchyma, collenchyma, and sclerenchyma cells.

Collenchyma characteristics

Derived from celery fibers; provides support.

Sclerenchyma role

Hard fibers responsible for structural support.

Pith definition

Middle of the stem, containing nutrients.

Procambium function

Gives rise to vascular cambium; produces xylem and phloem.

Root Structure components

Contains epidermis, cortex, endodermis, stele, and Casparian strips.

Stele description

Central cylinder containing vascular tissues in roots.

Caspian strips function

Prevent unregulated water movement between endodermal cells.

Apoplastic vs Symplastic pathways

Distinct routes of water movement in plant roots.

Root nodules significance

House bacteria that fix nitrogen for the plant.

Mycorrhizae importance

Fungal association with roots assists in nutrient uptake.

Abiotic Fixation process

Involves non-organism methods like lightning to convert nitrogen.

Biotic Fixation process

Utilizes bacteria to convert atmospheric nitrogen into usable forms.

Usable nitrogen forms for plants

Nitrate (NO3), Nitrite (NO2), Ammonia (NH3).

Vegetative Asexual Reproduction modes

Include runners, rhizomes, corms, tubers, and bulbs.

Parthenogenesis definition

Development of an egg without fertilization.

Propagation method

Cutting a piece of a plant to allow it to grow.

Plant Development stages

Germination followed by upward growth (epicotyl) and downward growth (radicle).

Positively Phototropic growth

Growth in response to light, directing stem upward.

Statoliths function

Sensing movement in plant growth, aiding gravitropism.

Meristematic Tissues role

Contain undifferentiated cells for ongoing plant growth.

Apical Meristems function

Responsible for increase in plant height.

Lateral Meristem significance

Contributes to plant diameter growth.

Three Primary Meristems

Includes protoderm, ground meristem, and procambium.

Exchange & Transport in plants

Gases, nutrients, and water are obtained through internal fluid systems.

Gas exchange initiation

Starts with stomata, roots, and lenticils.

Fluid movement in xylem mechanics

Combines adhesion, cohesion, evaporation, and transpiration pull.

Transpiration Pull definition

Main force that helps move water up in plants.

Drawback of Transpiration Pull

Requires significant water loss, critical in dry conditions.

Fluid movement in Phloem description

Mass flow transports sugars from source to sink.

Kingdom Animalia classification

Organisms that are multicellular, heterotrophs, and lack cell walls.

Two Major Groups of Kingdom Animalia

Invertebrates (no backbone) and vertebrates (with backbone).

Phylum Chordata examples

Includes vertebrates like fish, amphibians, mammals, and reptiles.

Metazoa definition

Transition from single-celled protists to multicellular animals.

Advantages of multicellularity

Larger size, increased mobility, stable internal environments.

Radial Symmetry characteristics

Can be divided regularly along a central axis; lack head.

Bilateral Symmetry characteristics

Divided down a central line; features head with sensory structures.

Asymmetry definition

Lack of symmetry, as seen in sponges.

Ontogeny recapitulates phylogeny meaning

Significant evolutionary similarities observed in vertebrate embryos.

Exoskeleton advantages

Provides structure and protection but limits growth.

Largest animal on the planet

Blue whale, recognized for its massive size.

Largest organism on the planet

Humungous fungus.

Significant organism in terrestrial transition

Reptiles with shell-covered eggs.

Species diversity hot spots

Tropical rain forests and coral reefs.

Creatures with closed circulatory system

Flatworms are the first recognized with this system.

Secondary Compounds function in plants

Defend against insects and are used medicinally.

Embryology definition

Study of early developmental patterns in organisms.

Radial Cleavage pattern

Cells arranged beside or on top of previous ones; deuterosome feature.

Spiral Cleavage pattern

Cells placed at junctions of previous cells; protostome feature.

Determinate Cell Fate definition

Early determination of cell fate in protostomes.

Indeterminate Cell Fate definition

Late determination of cell fate, allowing for twinning.

Developmental Stages in embryology

Includes morula, blastula, gastrulation, gastrula, germ layers.

Blastula definition

Hollow ball of cells formed after morula in development.

Gastrulation significance

Process of cell pushing inward to form layers.

Germ Layers roles in development

Layers that give rise to different organs in multicellular organisms.

Blastopore function

Opening connecting body cavity to the outside; can form mouth or anus.

Schizocoely vs Enterocoely

Two ways to develop body cavities in protostomes and deuterostomes.

Pseudocoelom definition

Partially lined body cavity, considered a false coelom.

Protostome vs Deuterostome distinction

Blastopore becomes mouth first in protostomes, or anus in deuterostomes.

Extinct vs Extant meaning

Extinct are no longer existing, extant still exist.

Phylum Porifera characteristics

Includes sponges; often have poorly defined tissues.

Three body plans of sponges

Asconoid, syconoid, leuconoid.

Amoebocytes function in sponges

Can transform into any sponge cell type.

Gemmules role in asexual reproduction

Dormant structures released during unfavorable conditions.

Dioecious vs Monoecious definition

Dioecious has male and female individuals; monoecious has both reproductive parts.

Classifications of Cnidaria

Includes Hydrozoa, Scyphozoa, and Anthozoa.

Hydrozoans characteristics

Can be polypoid or medusoid; contain polymorphic forms.

Class Scyphozoa characteristics

Mainly medusoid; includes jellyfish.