BIO 311D Lecture 21: March 8th Lecture Notes
Document Summary
Fungi use pheromones (sexual signaling molecules) to communicate mating type for. Sexual reproduction: molds produce haploid spores by mitosis and form visible mycelia, yeasts reproduce asexually by cell division and pinching of bud cells. Starfish: parthenogenesis new individual forms from unfertilized egg. Can"t do it: hermaphroditism individual has male and female reproductive systems, two hermaphrodites can mate or some self-fertilize, some undergo sex reversal [ex: clown fish of dom. Male becomes: sexual is better when environment changes. (less adaptation) female, when no female around, a sexual advantageous in stable, favorable environments. Reproductive cycles related to seasons controlled by hormones and environmental cues: temperature often common cue, ovulation release of mature eggs at midpoint of female cycle. Elements needed for survival: water, oxygen and carbon dioxide, other elements (nitrogen, calcium, sodium, magnesium, iron, etc. ) Coordination and control within multicellular organism: chemical signaling w/ hormones and/or nervous system. adaptations to similar environmental challenges, hormones can affect more than one region in body.
