Plant reproduction Reproduction in plants Sexual reproduction Formation

Plant reproduction

Reproduction in plants Sexual reproduction Formation of gametophyte (male or female plant or a single plant with male and female parts) Asexual reproduction Formation of sporophyte (plant makes spores which are asexual reproductive cells)

Recall. . Carpel = female reproductive floral part, comprising a stigma, style, ovary, and ovule Stigma = sticky surface on top of the style Style = tube like stalk that leads to the ovary Ovary = contains one or more ovules each of which forms a seed when it is fertilized

Flower Parts • Not all flowers have every part… Stamen = male reproductive floral part, comprising of an anther and a filament Anther = floral organ that produces pollen Filament = thin stalk that supports the anther (raises the anther above the female organ)

Sexual Reproduction in Angiosperms (seed plants) Flowers = key organs in sexual reproduction of angiosperms

Mechanisms of sexual reproductionpollination Cross-pollination – transfer of pollen grains from one plant to another – Example: Most plants • Self-pollination – transfer of pollen from one flower to another on the same plant – Example: Wheat, peas

Pollinators Help with the process of pollination of the plant. Examples of pollinators are: • Insects: bees, wasps, etc. • Animals: cows, sheep, etc • Wind

Seed Plants (Angiosperms) undergo Sexual Reproduction • Meeting (fertilization) of two haploid cells (sperm + egg) • Fruit= mature ovary inside seed plants (angiosperms) o Inside fruit seeds o Resulting embryo from fertilization grows in the seed

Function of seeds: § Carry the embryo to a new location (this means that the resulting new plant is introduced to new area) § Protects and nourishes the embryo (the seed is also a store for food)

Benefits of Sexual Reproduction • high level of genetic diversity • seeds dispersed – may have less competition for resources • seeds can remain dormant for long periods of time – germinate when conditions are favourable

Costs of Sexual Reproduction • requires specialized structures and cells that are devoted entirely to reproduction • which takes up a lot of resources • during times of scarcity sexual reproduction can lower the chances of survival

Examples of sexually reproducing flowers Daffodils Evening Primrose Golden Rod

Asexual Reproduction in Seed Plants • a single parent produces offspring by cell division • mitosis of diploid cells genetically identical individuals • Example: take a stem cutting and place it in water – get more plants

Reproduction in plants Sexual reproduction Formation of gametophyte (male or female plant or a single plant with male and female parts) Asexual reproduction Formation of sporophyte (plant makes spores which are asexual reproductive cells)

Reproduction in non-seed plants • Non-seed plants also undergo asexual reproduction Examples: Mosses Ferns

Benefits of Asexual Reproduction • if plant has a beneficial trait that allows it to survive then all offspring will have the same trait • no need for specialized reproductive structures (faster reproduction) • only need one plant • produce more robust offspring = higher survival rate

Costs of Asexual Reproduction • lack of genetic diversity! • If the environment changes drastically the population may not have enough genetically diverse individuals to survive the change • = extinction