BIO 203 Lecture Notes - Lecture 27: Coleoptile, Apical Dominance, Primordium
1 Dec 2016
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Document Summary
A behavior is the response of an organism to its environment. Like animals, we can seek both proximate and ultimate explanations for these behaviors. Ultimate explanations why: genes, proteins, metabolism and hormones, learning, the adaptive benefit of a trait to the individual, evolution and phylogenetic constraints; certain behaviors more likely in certain lineages. Each pumpkin seed contains a small plant (an embryo) Plants respond to various environmental stimuli: light, gravity, touch, consumers, voltage (electricity, radiation, water, crowding or competition. We will consider 5 types of plant hormones: Cytokinin: cell division (cytokinesis) (making more cells) Abscisic acid (aba): growth inhibition, stomata closing. Ethylene: fruit ripening, seedling growth, leaf dropping stratification. Arabidopsis seeds need to wait through the winter before germinating = Honey locust seeds are very well protected from digestion, and pass through. The decision to (cid:498)stay asleep(cid:499) or (cid:498)wake up(cid:499) is made by opposing signals from ga and the animals that eat the pods.
