exam 4

Eukarya

Domain of organisms with complex cells containing a nucleus.

Archaea

Domain of single‑celled prokaryotic organisms.

Bacteria

Single‑celled prokaryotes; can be pathogenic or beneficial.

Phytoplankton

Photosynthetic single‑celled aquatic organisms; primary producers.

Plasmid

Small circular DNA molecule in bacteria, exchanged during conjugation.

Binary fission

Asexual reproduction in bacteria where the cell divides into two identical cells.

Pathogenic

Capable of causing disease.

Antibiotic resistance

Evolution of bacteria that allows them to survive antibiotic treatment.

Heterotrophic (fungi)

Must consume organic material for energy.

Spores

Reproductive units used by fungi for dispersal.

Hyphae

Threadlike structures forming the body of fungi.

Chitin

Structural substance in fungal cell walls and arthropod exoskeletons.

Lichen

Symbiotic relationship between a fungus and photosynthetic algae.

Autotrophic

Produce their own food via photosynthesis.

Xylem

Plant tissue that transports water upward.

Angiosperms

Flowering plants that produce fruit.

Gymnosperms

Seed‑producing plants that do not form flowers or fruits.

Pollen

Male gametophyte that carries sperm for fertilization.

Heterotrophic (animals)

Consume organic material for energy.

Radial symmetry

Body symmetry around a central axis (e.g., jellyfish).

Bilateral symmetry

Body symmetry with distinct left and right sides (e.g., humans).

Polyp/Medusa

Two body forms of cnidarians; polyp is sessile, medusa is free‑swimming.

Coelom

Fluid‑filled body cavity in animals.

Porifera

Sponges; no true tissues, asymmetrical.

Cnidaria

Jellyfish and coral; radial symmetry, stinging cells.

Platyhelminthes

Flatworms; bilateral symmetry, no body cavity.

Annelida

Segmented worms such as earthworms.

Arthropoda

Insects, spiders, crabs; exoskeleton, jointed limbs.

Echinodermata

Sea stars and sea urchins; radial symmetry, spiny skin.

Chordata

Vertebrates like fish, birds, mammals; possess a spinal cord.

Carrying capacity

Maximum population size an environment can sustain.

Trophic level

A feeding position in a food chain (producer, consumer, etc.).

Primary producers

Organisms that convert solar energy to chemical energy (plants, phytoplankton).

Decomposers

Organisms that break down dead material, recycling nutrients.

Energy transfer

Only about 10 % of energy moves from one trophic level to the next.

Symbiosis

Close long‑term interaction between two species, often beneficial.