Biology 1153 final exam study set

Origin of land plants

All green algae and land plants share a common ancestor over 1 billion years ago, supported by DNA sequence data.

Challenges on land

Plants had to overcome issues like water loss, sun protection, and effective gamete dissemination.

Adaptations to terrestrial life

Plants evolved mechanisms like moving water within, specialized vascular tissues (xylem and phloem), and waxy cuticles for protection.

Haplodiplontic life cycle

All land plants exhibit a life cycle with multicellular haploid and diploid stages, known as alternation of generations.

Bryophytes

Mosses, the closest living descendants of early land plants, lack tracheids but have conducting cells and mycorrhizal associations.

Vascular plants

Have xylem and phloem for water and nutrient transport, enabling height growth and hormone distribution.

Plant cell types

Dermal tissue protects, ground tissue supports and stores, and vascular tissue conducts water and nutrients.

Meristem cell division

Meristems at tips and roots produce new cells, while lateral meristems increase stem/root diameter.

Roots

Anchor plants and absorb water; consist of root cap, cell division, elongation, and maturation zones.

Stems

Support above-ground organs, grow from apical and lateral meristems, and have vascular tissue organization differences in monocots and eudicots.

Leaves

Photosynthetic organs with different morphological groups like microphylls and megaphylls, and eudicot leaves with flattened blades and petioles.

Transport in Plants

Water and minerals enter roots, move through xylem, and exit through stomata due to cohesion, adhesion, and osmosis.

Osmotic concentration

Refers to the concentration of solutes in a solution.

Hypertonic

Describes a solution with a higher solute concentration compared to another solution.

Hypotonic

Describes a solution with a lower solute concentration compared to another solution.

Isotonic

Refers to two solutions having the same concentration of solutes.

Osmosis

The movement of water across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.

Turgid

The swollen state of a plant cell due to high water uptake.

Plasmolysis

The shrinking of a cell due to water loss.

Osmotic pressure

The force required to prevent the flow of water across a semipermeable membrane.

Water potential

The energy status of water in a system, influenced by solute concentration and pressure.

Xylem transport

The movement of water and minerals through the xylem tissue in plants.

Guard cells

Specialized cells that control the opening and closing of stomata.

Stomatal opening

The process by which stomata open due to turgor pressure in guard cells.

Phloem transport

The movement of carbohydrates and other substances through the phloem tissue in plants.

Pressure flow hypothesis

A model explaining the movement of carbohydrates in the phloem from source to sink tissues.

Topsoil

The upper layer of soil where most plant roots are found, containing a mixture of mineral particles, organisms, and humus.

Suberin

Found in cell walls of subterranean plant organs

Physical damage and pathogens

Damage to dermal surface can create entry site for pathogens

Fungal invasion phases

Windblown spore lands, germinates, forms adhesion pad, hyphae grow, differentiate into haustoria

Chemical defenses

Plants employ toxins to kill herbivores or deter grazing behavior

Secondary metabolites

Modified pathways produce chemicals affecting herbivores like alkaloids, tannins, and plant oils

Allelopathic plants

Secrete chemicals to inhibit growth of nearby plants, reducing competition

Ricin poison

Alkaloid from castor bean plant, can be lethal, blocks protein translation

Plant protection by animals

Ants protect acacia trees from harmful herbivores

Plant sensory systems

Response to light, gravity, and hormones like auxin

Photomorphogenesis

Phytochrome involved in light-triggered development, seed germination, and shoot elongation

Phototropism

Directional growth response to light, compensating for plant immobility

Blue light receptors

Phototropin 1 regulates auxin flux in shoots in response to blue light

Gravitropism

Plant response to gravity, shoots exhibit negative gravitropism, roots positive

Amyloplasts

Starch-storing organelles involved in gravity perception in roots

Hormones and sensory systems

Auxin promotes cell growth and influences plant bending towards light

Flowering pathways

Light, temperature, gibberellin, and autonomous pathways regulate flowering in plants

Flower morphology

Calyx, corolla, androecium, and gynoecium make up the structure of flowers

Embryo development

Double fertilization, embryo differentiation, and formation of tissue systems in plants

Germination

Emergence of radicle through seed coat, requires water, oxygen, and metabolic reserves

Patterns of Behavior

Once initiated, behaviors tend to continue to completion even if the initial stimulus is removed.

Neural Mechanisms

Rapid behaviors are controlled by simple neural mechanisms involving a few neurons.

Hormonal Influence

Hormones like testosterone, estrogen, and glucocorticoids influence behaviors such as territorial behavior, courtship, mating, and stress.

Neurotransmitters

Chemicals like serotonin and dopamine influence behaviors.

fMRI

Functional Magnetic Resonance Imaging is used to measure neuron activity.

Behavioral Genetics

Study of how genetics and environmental factors influence behavior.

Vasopressin and Oxytocin

Hormones released during mating that regulate water retention and birth contractions.

Habituation

Decrease in response to repeated stimuli without positive or negative consequences.

Associative Learning

Conditioning where behaviors are learned through associations between stimuli or responses.

Operant Conditioning

Learning through trial and error by associating behaviors with rewards or punishments.

Instincts

Innate behaviors that guide learning and associations.

Imprinting

Forming social attachments or preferences that influence behavior later in life.

Evolutionary Factors

Selection, mutation, and genetic variation influence changes in populations and species.

Species Concepts

Biological species concept defines species as reproductively isolated groups.

Speciation

Allopatric speciation results from geographic isolation, leading to the formation of new species.

Adaptive Radiation

Occurs in new environments with abundant resources and few species, leading to diversification.

Taxonomy

Science of classifying organisms into groups based on shared characteristics.

Monophyletic Group

Group of organisms including a common ancestor and all its descendants.

Root system

anchors the plant and used to absorb water and ions from the soil

shoot system

consists of supporting stems, photosynthetic leaves, and reproductive flowers. Repetitive units consist of internode, node, leaf and axillary bud.

meristems

·      Located at the tips of stems and roots

·      Produce hormones that repress the development of the lateral bud

·      When meristem is interrupted, the plant will no longer be able to grow from that tip.

·      Lateral buds will then be released from the repression

types of plant tissue

dermal, ground, and vascular

dermal plant tissue

·      Forms the epidermis

·      One cell layer thick

·      Forms the outer protective covering of the plant

·      Covered with fatty cutin layer

·      Mostly epidermal cells

·      Also consists of special cells, including guard cells, trichomes, and root hairs.

ground plant tissue types

Parenchyma, Collenchyma, Sclerenchyma

parenchyma

function in storage, photosynthesis and secretion

·      Most common type of plant cell

·      Living protoplasts

·      Most only have primary cell walls

collenchyma

protection and support

·      Provides flexible support for plant organs

·      Allows bending without breaking

·      Living protoplasts

·      Lacks secondary cell walls

sclerenchyma

protection and support

·      Tough thick walls

·      Usually lack living protoplasts at maturity

·      Secondary cell walls often contain lignin

·      Two general types, fibers and sclereids. Both strengthen tissues.

all plants are…

haplodiplontic