Seed Plant Reproduction and Angiosperm vs Gymnosperm Features

Seed plant dominant life stage

Sporophyte phase is dominant.

Why fertilization in seed plants is not water dependent

Seeds and pollen allow reproduction without water.

What heterosporous means in seed plants

Plants produce two types of spores: megaspores and microspores.

Megaspores develop into

Female gametophyte that produces the egg.

Microspores develop into

Male gametophyte (pollen) that produces sperm.

Function of seeds

Protect embryo with seed coat, contain nutritive tissue, and allow dispersal far from the parent plant.

Function of pollen

Male gametophyte that delivers sperm to the egg through a pollen tube.

Gymnosperms relationship to angiosperms

Gymnosperms and angiosperms are sister taxa.

Gymnosperm seeds

Naked seeds not enclosed in fruit.

Gymnosperm reproduction structures

Male pollen cones and female ovulate cones.

Monoecious gymnosperms

Male and female cones on the same plant.

Dioecious gymnosperms

Male cones and female cones on separate plants.

Gymnosperm pollination method

Wind pollination.

Gymnosperm xylem cells

Tracheids transport water and minerals.

Gymnosperms are heterosporous

Microsporangia produce microspores and megasporangia produce megaspores.

Location of microsporangia in gymnosperms

On male pollen cones.

Microspores become

Male gametophyte called pollen.

Location of megasporangia in gymnosperms

On female ovulate cones.

Megaspores become

Female gametophyte that produces the egg.

Cells inside pollen grains

Generative cell and pollen tube cell.

Function of generative cell

Undergoes mitosis to produce sperm.

Function of pollen tube cell

Grows the pollen tube toward the egg.

Seed tissues in gymnosperms

Seed coat (sporophyte), nutritive tissue (gametophyte), embryo (new sporophyte).

Angiosperm key adaptations

Flowers and fruits.

Pollination in angiosperms

Wind, insects, birds, and mammals.

Angiosperm xylem cells

Vessel cells that conduct water more efficiently than tracheids.

Flower female structure

Carpel (gynoecium) composed of stigma, style, and ovary.

Flower male structure

Stamen (androecium) composed of filament and anther.

What the ovary contains

Ovules which are megasporangia.

What the anther contains

Microsporangia that produce microspores.

Angiosperms are heterosporous

Microsporangia produce microspores and megasporangia produce megaspores.

Microspores develop into

Male gametophyte (pollen).

Megaspores develop into

Female gametophyte producing the egg.

Female gametophyte development

Megaspore divides three times by mitosis to produce 7 cells and 8 nuclei.

Cells of the mature embryo sac

Egg, two synergids, three antipodal cells, and central cell with two polar nuclei.

Double fertilization definition

One sperm fertilizes egg forming zygote, second sperm fuses with polar nuclei forming endosperm.

Endosperm function

Nutritive tissue for embryo development.

What fruit is

Ovary walls thicken after fertilization to form fruit.

Purpose of fruit

Protect seeds and aid in seed dispersal.

Monocots cotyledons

One cotyledon.

Monocot flower symmetry

Multiples of 3.

Monocot leaf venation

Parallel venation.

Monocot root system

Fibrous roots.

Monocot vascular bundles

Scattered in the stem.

Monocots woody tissue

No secondary xylem.

Eudicots cotyledons

Two cotyledons.

Eudicot flower symmetry

Multiples of 4 or 5.

Eudicot leaf venation

Networked venation.

Eudicot root system

Taproot with smaller roots.

Eudicot vascular bundles

Arranged in a ring.

Eudicot woody tissue

Can have secondary xylem (wood).

Angiosperm coevolution with animals

Plants and insects/animals evolved together influencing pollination and defenses.

Examples of plant defenses in coevolution

Toxins, thorns, spines, and bark.

How plants attract pollinators

Nectar, flower color, and pollen rewards.

Percentage of angiosperms that rely on animals for pollination

About 80%.

Importance of plant biodiversity

Provides food, balances ecosystems, protects water systems, moderates climate, and provides shelter for animals.

Threats to plant biodiversity

Human population growth, deforestation, agriculture expansion, and energy extraction.

Why plants are essential for life

No plants means no animals and no humans.