Undifferentiated meristem cells at the growing tips of plants give rise to new plants
Resulting new plants are genetically identical to their parents and thus are called clones
Sexual Reproduction in Plants
Offspring are genetically different from the parents
Offspring are packaged in a protective seed, which can be long lived and can disperse the offspring some distance from the parents
In flowering plants (angiosperms), the seed itself is contained inside a fruit, which may protect developing seeds and aid in their dispersal
Sporophyte
The diploid form of plants that consists of roots, shoots, leaves, and reproductive structures such as flowers and fruits
Gametophytes in Angiosperms
Pollen grains (male gametophytes or microgametophytes)
Embryo sac (female gametophyte or megagametophyte)
Double Fertilization
1. Pollen tube grows toward the embryo sac and releases two sperm cells
2. One sperm cell fuses with the egg cell to form the diploid zygote
3. The other sperm cell fuses with the two polar nuclei to form the triploid endosperm nucleus
Gametes
Sex cells produced by meiosis, with sperm being the male gamete and ova being the female gamete
Estrous Cycles
Reproductive cycles found in most mammals
Gametogenesis
1. Spermatogenesis (in males)
2. Oogenesis (in females)
External fertilization
Many gametes are released into the water by each sex at the same time and place. Water is required because animal sperm must swim to the eggs. Water also protects gametes from drying out. Species which have external fertilization are either aquatic or return to water for reproduction (some invertebrates, fishes and amphibians)
Menstrual cycles
Reproductive cycles found in humans and some other primates.
Gene
A stretch of DNA that contains the instructions for making protein
Genotype
Genes that are present in the DNA of an organism
Phenotype
What an organism looks like as a consequence of the genotype and its environment
Dominant traits
Traits that are expressed
The Punnett Square
A tabular summary of every possible combination of one (1) maternal allele with one (1) paternal allele for each gene being studied in the cross.