Glossary- 17- (Evolution) Flashcards
Gametophyte
The haploid phase of the life history. Produces the male and female gametes.
Heteromorphic
Refers to algal or plant life histories in which the haploid gametophytic and diploid sporophytic phases are different (often very different) in size and structure.
Phragmoplast
The mitotic process in higher-plant organisms in which the nuclear envelope is non-persistent during division, and the mitotic spindle remains intact, keeping the daughter nuclei relatively far apart during cell-plate formation.
Phycoplast
The mitotic process in algal organisms in which the nuclear envelope is persistent throughout division, and the collapse of the mitotic spindle results in the close proximity of the daughter nuclei during cell-plate formation.
Sporophyte
The diploid phase of the life history. Meiosis takes place here within sporangia to produce haploid spores in plants that have an alternation of generations
Tracheids
The water-conducting cells of plants, secondarily thickened and dead when functioning. They link up to form conducting channels in the vascular cylinder.
Vascular System
The water- and food-conducting tissues; consists of xylem and phloem
Xylem
Water-conducting tissue consisting of tracheids and associated strengthening cells (fibres) and parenchyma
Caenozoic Era
The time of flowering plant dominance. From 65 million years ago to the present day.
Gondwana
An ancient land mass that comprised the continents of Australia, Antarctica, India, South America and Africa.
It began to break up during the Cretaceous and the southern conti8nents gradually moved in their current positions
Heterosporous
A plant that produces two types of meiotic spore. The smaller microspore gives rise to the “male-” or microgametophyte that produces sperm; the larger megaspore gives rise to the “female-” or megagametophyte that produces the egg cell.
Homosporous
A plant that produces only one type of meiotic spore. The spores germinating to produce only one type of gametophytes on which antheridia and archegonia are produced.
Mesozoic Era
Time of cycad and conifer dominance (and dinosaurs). 250-65 million years ago.
Carpel
A “female” part of a flower. It consists of a stigma (pollen receptive area) that is elevated on a style above the ovary (which contains ovules)
Endosperm
Triploid tissue resulting from the fusion of a sperm cell with the two polar nuclei of the megagametophyte. It is the food reserve for the developing embryo.
Fertilization
The fusion of sperm and egg (or polar )cells
Pollination
The transfer of pollen from anthers to the stigma
Stamen
A “male” part of a flower. It consists of an anther (pollen sac) borne on a sterile filament (stalk)
Germ layer
Layer of cells in embryo that develops into body features
Diploblastic
Two germ layers
Triploblastic
Three germ layers
Coelom
Body cavity within the mesoderm
Blastopore
Opening in the blastula during initial cell development
Protostome
Blastopore become mouth, anus either forms later or at same time as mouth
