Comprehensive Plant Biology and Evolution: Key Concepts and Ecosystem Roles

Life is characterized by:

order, evolutionary adaptation, regulation, metabolism, growth and development, response to the environment, and reproduction.

Plants are:

living, photosynthetic, stationary organisms within the Eukarya domain.

Eukarya domain:

organisms with complex, eukaryotic cells that have internal organization.

Plants are unique:

multicellular terrestrial organisms with specialized organs.

Four major groups of plants:

bryophytes, lycophytes, ferns, and seed plants.

Bryophytes: (mosses

liverworts, hornworts)

Bryophytes:

nonvascular plants that lack true roots and leaves and require water for reproduction.

Lycophytes and ferns:

seedless vascular plants.

Key adaptations of vascular plants:

vascular tissue, well-developed roots, and leaves.

Seed plants (gymnosperms and angiosperms):

the most successful group of plants; they use pollen and seeds for reproduction and are independent of water. Plants are called:, autotrophs (self-feeders) and primary producers.

Plants are the base of the food chain because:

they use sunlight to create their own food through photosynthesis, providing energy for all other organisms (heterotrophs).

The equation for photosynthesis is:

6CO2 +6H2O+light→C6H12O6+6O2

Evolution is:

the biological process of genetic change over time, also known as descent with inherited modification.

Genetic variation:

differences in genes or DNA segments among individuals in a population.

Alleles:

alternate versions of a gene.

Evidence for evolution includes:

the fossil record and artificial selection.

Oxygen Revolution:

occurred about 2 billion years ago, initiated by cyanobacteria performing photosynthesis and drastically changing the Earth's atmosphere. Natural Selection:, a directed force that favors advantageous, heritable traits, causing them to accumulate in a population over time.

Mutation:

the ultimate random source of new alleles and the raw material for other evolutionary forces.

Gene Flow:

the movement of individuals and their genetic material between populations, which reduces genetic differences.

Genetic Drift:

the random loss of alleles in a population, particularly in small populations.

Bryophytes are:

nonvascular and lack true roots and leaves.

Seedless vascular plants are:

vascular and have true roots and leaves.

Both bryophytes and seedless vascular plants:

are seedless and require water for reproduction.

Gymnosperms:

"naked seed" plants that bear seeds in cones, e.g., conifers.

Angiosperms:

"seed vessel" plants that bear seeds within flowers and fruits, e.g., most fruits, vegetables, and grains.

Both gymnosperms and angiosperms:

are seed plants and use pollen for reproduction.

Angiosperm evolutionary adaptations:

flowers for attracting pollinators and fruits for protecting and dispersing seeds. Four major groups of primary metabolites:, carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates:

made of carbon, hydrogen, and oxygen.

Proteins:

made of carbon, hydrogen, oxygen, and nitrogen.

Nucleic Acids (DNA/RNA):

made of carbon, hydrogen, oxygen, nitrogen, and phosphorus.

Three major tissue systems:

dermal, vascular, and ground tissue.

Dermal tissue:

the outer protective covering of the plant.

Vascular tissue:

composed of xylem and phloem.

Xylem:

transports water and minerals from the roots upwards.

Phloem:

transports sugars from a source to a sink.

Ground tissue:

fills the space between dermal and vascular tissues, functioning in storage, photosynthesis, and support.

The root system:

absorbs water and nutrients, anchors the plant, and stores food.

The shoot system:

consists of stems and leaves.

Leaves:

the primary sites of photosynthesis.

Transpiration:

the passive process where water evaporates from leaves, creating tension that pulls water up the xylem from the roots.

Translocation:

the active process where sugars are moved through the phloem from a source (e.g., leaf) to a sink (e.g., root or fruit). Energy flows through an ecosystem:, from the sun to producers, then to consumers, with some energy lost as heat at each trophic level.

Chemicals cycle through an ecosystem:

recycled by decomposers.

Decomposers:

organisms (e.g., fungi and bacteria) that break down dead organic matter and release nutrients back into the ecosystem.

Plants' role in the carbon cycle:

fix atmospheric CO2 into carbon-based compounds through photosynthesis.

Human impact on the carbon cycle:

burning fossil fuels adds excess carbon to the atmosphere.

Ecosystem services of plants:

help mitigate climate change by forming a soil carbon sink and cooling the planet through transpiration.