Updated bio 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 plants face on land

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

Colonization of land

Initially, land lacked soil, insects, and land animals, but fungi were present to aid in nutrient availability for plants.

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.

Angiosperms (flowering plants)

Small and dependent gametophyte, Large sporophyte

What plant requires water for sexual reproduction

Bryophytes

Male Gametangia

Antheridia (anther)

Female Gametangia

Archegonia

All plants are…

Haplodiplontic

Bryophytes

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

Seed plants

Seed plants are crucial adaptations providing dormancy, protection, food, and embryo dispersal. (Ex:Conifers, pine trees)

Vascular tissue

Xylem conducts water, while phloem transports nutrients; gymnosperms have sieve cells, and angiosperms have more efficient sieve tube members.

Roots

Roots anchor plants, absorb water and ions, and can be taproots or fibrous; root structure includes the root cap, zones of division, elongation, and maturation.

2 systems that make up the vascular system

Root system and shoot system

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.

Stems

Stems support above-ground organs, undergo growth from apical and lateral meristems, and have vascular tissue organization distinguishing monocots and eudicots.

meristems

located at tips of stems and roots, produce hormones to repress the development of lateral bud

what happens when the meristem is interrupted?

plant will no longer be able to grow from that tip.

what are the 3 types of plant tissues?

dermal, ground, 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.

What are the 3 types of GROUND TISSUE?

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.

Leaves

Leaves are photosynthetic organs with different morphological groups like microphylls and megaphylls; eudicot leaves have flattened blades and may possess stipules.

Transport in plants

Water and minerals enter roots, move through xylem, and exit through stomata due to transpiration; long-distance movement is driven by local changes.

Transport of water

Movement of water in plants facilitated by cohesion and adhesion.

Osmosis

Movement of water at a cellular level.

Osmotic concentration

Different concentrations of solutions - hypertonic, hypotonic, and isotonic.

Osmotic pressure

Force needed to stop osmotic flow in cells.

Hypertonic solution

higher solute concentration

hypotonic solution

lower solute concentration

isotonic solution

when two solutions have the same osmotic concentration, at an equilibrium.

Water potential

Represents the free energy of water and predicts water movement.

Water and Mineral Absorption

Water and minerals enter plants through roots and move through cell layers.

Transport routes through cells

Apoplast, symplast, and transmembrane routes for movement.

Guard cells

Cells that regulate stomatal opening and closing.

Phloem transport

Movement of carbohydrates, hormones, and other substances in plants.

Xylem transport

Movement of water and minerals

Pressure flow hypothesis

Model describing carbohydrate movement in phloem.

Soil

Highly weathered outer layer of the earth's crust containing microorganisms.

Topsoil

Mixture of mineral particles, living organisms, and humus where most roots are found.

Prevention of erosion

Methods like intercropping and conservation tillage to prevent soil erosion.

Plant nutrients

Essential elements like macronutrients and micronutrients for plant growth.

Mycorrhizae

Symbiotic associations with fungi enhancing nutrient uptake in plants.

Carbon dioxide and photosynthesis

Role of CO2 in the Calvin cycle and photorespiration in plants.

Dermal tissue system

The first line of defense in plants, consisting of epidermal cells secreting wax to protect against water loss and attacks.

Physical damage and invaders

Damage to the dermal surface can create entry points for pathogens, allowing invaders like parasitic nematodes to penetrate plant cell walls.

Fungal invasion phases

Windblown spores land on leaves, germinate, form adhesion pads, grow hyphae through cell walls, and differentiate into haustoria.

Chemical defenses

Plants use toxins like alkaloids, tannins, and plant oils to deter herbivores and protect themselves.

Secondary metabolites

Plants modify metabolic pathways to produce chemicals like alkaloids, tannins, and plant oils that affect herbivores negatively.

Allelopathic plants

Plants release chemicals to inhibit seed germination or growth of nearby plants, reducing competition for resources.

Ricin poison

A toxic alkaloid from castor bean plants that can block protein translation by inactivating ribosomes.

Plant-animal interactions

Ants protect acacia trees by attacking herbivores, while parasitoid wasps lay eggs in caterpillars to kill them.

Plant sensory systems

Plants respond to light through pigments like phytochrome, leading to photomorphogenesis and phototropism.

Photoperiodic pathway

Plants use day length to regulate flowering, with long day, short day, and day-neutral plants flowering based on light exposure.

Flowering pathways

Plants have genetic pathways like the light-dependent, temperature-dependent, gibberellin-dependent, and autonomous pathways that regulate flowering.

Flower structure

Flowers consist of calyx, corolla, androecium, and gynoecium, with trends in floral specialization related to pollination mechanisms.

Embryo development

Double fertilization leads to zygote and endosperm formation, with apical meristems giving rise to tissue systems in the embryo.

Critical developmental events

Angiosperms undergo key events like endosperm development, seed coat differentiation, and fruit formation during embryogenesis.

Germination

The process of radicle emergence through the seed coat, triggered by water imbibition and requiring oxygen for metabolic processes.

Fixed Action Pattern

A sequence of innate behaviors that is unchangeable and usually carried to completion once initiated.

Innate Behavior

Behaviors that are genetically programmed rather than learned.

Innate Release Mechanism

The perception of a key stimulus that triggers a specific motor program.

Hormones

Chemical messengers that influence behaviors and physiological processes.

Classical Conditioning

A type of associative learning where a neutral stimulus becomes associated with a meaningful stimulus to elicit a specific response.

Operant Conditioning

Learning through reinforcement or punishment of behaviors.

Ecological Niche

The role and position of an organism within its environment.

Competitive Exclusion

The elimination of one species by another due to competition for the same limited resources.

Keystone Species

A species that has a disproportionately large effect on its environment relative to its abundance.

Ecosystem

A community of organisms interacting with each other and their physical environment.

First law of thermodynamics

energy is neither created nor destroyed, however it changes from one form to another

second law of thermodynamics

whenever organisms use chemical-bond or light energy, some is converted to heat (entropy)

Basic water cycle

liquid water from earths surface evaporates into the atmosphere, water in the atmosphere is a gas, cools and falls to surface as precipitation

what are key elements of the environment?

temperature, water, sunlight, soil

Incoming and Outgoing Energy

Earth operates as an open system for energy, with the sun being the primary energy source. The balance between incoming and outgoing radiant energy is crucial for maintaining global temperatures.

Greenhouse Effect

Refers to the accumulation of heat on Earth due to certain gases trapping heat in the atmosphere, potentially leading to climate change.

Trophic Levels

Different levels in an ecosystem where organisms obtain their energy.

Autotrophs

self feeders, synthesizes organic compounds from inorganic precursors

photoautotrophs

uses light as an energy source

chemoautotrophs

uses energy from inorganic oxidation reactions

heterotrophs

CANNOT synthesize organic compounds from inorganic precursors (animals, protists that eat plants or other animals)

Productivity

The rate at which organisms in a trophic level produce new organic matter, including primary productivity by producers and respiration.

GPP

Gross Primary Productivity (GPP) is the total rate at which primary producers synthesize organic matter

NPP

Net Primary Productivity (NPP) is GPP minus the energy used for respiration.

Fate of Ingested Energy

Describes how energy is transferred between trophic levels, with a decrease in chemical-bond energy as it moves up the food chain.

Limits on Top Carnivores

The decline in energy transfer limits the number of top carnivores an ecosystem can support, with only a small fraction of energy passing through trophic levels.

Biosphere

Encompasses all living communities on Earth and is influenced by factors like solar radiation, atmospheric circulation, and oceanic patterns.

Solar Energy

Energy received from the sun, affecting global patterns of life on Earth and leading to variations in temperature and circulation.

Biomes

Different ecological regions like rainforests, deserts, and grasslands, determined by factors such as temperature and precipitation, influencing the distribution of life forms.

What are the 8 “main” biomes?

Tundra, Taiga, Temperate grassland, Tropical rainforest, Temperate deciduous forest, Temperate evergreen forest, Savanna, Desert.

Freshwater Habitats

Environments like lakes and ponds with unique characteristics such as oxygen levels, thermal stratification, and nutrient content, impacting the organisms living in them.

Photic Zone

area where light penetrates and photosynthesis is possible.

Littoral zone

shallows at the edge of lakes

Aphotic (benthic) zone

below light penetration level

Thermal Stratification

warm water is less dense than cold water and tends to float on top.

What term is used to best describe the cut off of oxygen supply to bottom waters

Thermal stratification

Epilimnion

warm, toxic, light