Exploring Phylogeny and Diversity of Life Forms

LUCA

Last Universal Common Ancestor. The shared ancestor that multiple organisms diverged from; approximately 3.5-3.8 billion years old (likely a bacteria)

Endosymbiosis

Organisms living inside one another

Haploid

One set of chromosomes (n)

Diploid

Two sets of chromosomes (2n)

Gametes

Sex cells (haploid)

Gametophyte

Gamete-producing structure, EX: ovaries and testicles

Meiosis

Cell division process which yields haploid gametes

Mitosis

Cell division process which yields identical diploid cells

Fertilization

Gametes unite (sperm and egg) gives rise to a zygote (2n/diploid), which divides through mitosis to give rise to a multicellular diploid (2n) form

Endospores

Dormant, tough, non-reproductive structure that ensures survival under difficult conditions

Horizontal Gene Transfer

While bacteria are asexual, they can swap their plasmids

Eukarya

Unicellular and multicellular organisms larger than prokaryotes

Protists

Most diverse eukaryotes, inherently difficult to classify