Life 103 Exam 1

Phylogeny

The study of the evolutionary history and relationships among species.

Phylogenetic Trees

Diagrams that show the inferred evolutionary relationships among various biological species based on similarities and differences in genetic characteristics.

Endosymbiotic Theory

The theory that certain organelles in eukaryotic cells originated as free-living prokaryotes that were engulfed by ancestral eukaryotic cells.

Prokaryotic Cells

Single-celled organisms that lack a nucleus and membrane-bound organelles.

Chemoautotroph

A microorganism that uses chemical energy to convert carbon dioxide into organic compounds.

Photoautotroph

An organism that makes its own carbon from light energy.

Chemoheterotroph

An organism that obtains carbon from other living things.

Photoheterotroph

An organism that obtains energy from light but acquires carbon from organic sources.

Horizontal Gene Transfer

The incorporation of genetic material from one organism to another without reproduction occurring via transformation, transduction, or conjugation.

Eukaryotic Supergroups

Four groups characterized by distinctive features: Excavata, SAR, Archaeplastida, and Unikonts.

Protist Importance

Protists play vital roles in ecosystems as primary producers, decomposers, and integral parts of the food chain.

Chitin

A long-chain polymer that is a primary component of fungal cell walls.

Cellulose

A carbohydrate that is a primary component of plant cell walls.

Haploid

A cell that contains one complete set of chromosomes.

Diploid

A cell that contains two complete sets of chromosomes.

Sporopollenin

A biopolymer that protects the zygote from desiccation in land plants.

Apical Meristems

Regions of fast mitosis for growth at root and shoot tips in plants.

Gymnosperms

A group of seed-producing plants characterized by the presence of seeds that are not enclosed in an ovary.

Spores

Unicellular reproductive units that develop into an organism under specific conditions.

Seeds

Reproductive structures that contain an embryo encased in a protective coat.

Xylem

The vascular tissue in plants that transports water and dissolved minerals from roots to leaves.

Phloem

The vascular tissue in plants that transports nutrients produced by photosynthesis from leaves to roots.

Excavata

Excavated groove

Stramenopiles:hairy flagella

Alveolates:membrane bound sacs

Rhizarians:amoebas

SAR Clade

Archaeplastida

Red and green algae

Unikonts

Animals and fungi

Alternation of Generations

Two haploid gametes fuse to form a diploid zygote, which develops into a sporophyte through multiple rounds of mitosis. The sporophyte produces haploid spores through meiosis, which then develop into gametophytes. The gametophytes produce gametes, and the cycle repeats

Gametophyte

The haploid phase of the alternation of generations that develops from spores and produces gametes (sperm and eggs) through mitosis.

Sporophyte

The diploid phase of the alternation of generations that develops from the fertilization of gametes and produces spores through meiosis.

Fertilization

Occurs when gametes from the gametophyte phase unite, leading to the formation of a diploid zygote, which develops into the sporophyte.

Bryophytes

Non-vascular land plants that include mosses, liverworts, and hornworts, typically characterized by a dominant gametophyte phase in their life cycle.

Adaptations of Bryophytes

A waxy cuticle to prevent desiccation, rhizoids for anchorage, and the ability to reproduce via spores.

Gametangia

Specialized structures in bryophytes where gametes are produced; include antheridia (male) and archegonia (female).

Stomata

Small openings on the surface of leaves that allow gas exchange while minimizing water loss.

Dominant Fungi Phase

Haploid gametophyte

Dominant bryophyte and gymnosperm phase

diploid sporophyte