Vascular Seed PlantsPlants that plan ahead…

Seeds – Overview and StructureSeed plants, perhaps unsurprisingly, produce… seeds.

A seed is a structure that contains: An immature sporophyte (remember –

sporophytes often become the BIGGEST part of a more complex plant).

Food (carbs and fats) to keep it alive until it finds suitable growth conditions.

Types of Vascular Seed Plants Further broken into two major groups:1. Gymnosperms

Plants whose seeds are “exposed” (gymno = “naked”) as they develop on the mature sporophyte.

2. Angiosperms Plants whose seeds develop in a closed

ovary (this later develops into a fruit).- You read that correctly. We eat a balanced diet that includes a healthy amount of plant ovaries. Eat up!

Gymnosperms‘tis the season!

Gymnosperms – Typical organisms Coniferous trees – trees that put out

cones that will store spores. Eg: Spruce, pine, and fir Found in nearly every climate (guess

where it isn’t found!)

Typical Orgnisms cont’d Ephedra sp. – smaller shrubs; produce

compounds that have well-known medicinal uses.

Increase metabolism, heart rate, and ventilation (breathing). Used to be used as performance-

enhancing drugs. Now banned in the US; highly controlled

in Canada.

Typical Organisms cont’d Cycads – resemble short, shrubby palm

trees. Date back to the same era as the

dinosaurs.The Nomosaurus enjoying a light

gymnosperm salad. Entrée of sauteed

simians soon to follow.

Gymnosperm Structure Needle-like leaves – small surface

area, prevents loss of water and nutrients. Many (NOT all) gymnosperms are

“evergreens” – don’t drop their leaves.

Structure cont’d

Has roots which are seldom deep but cover a large area.

Produce cones which store and protect either male or female spores.

Structure cont’d Gymnosperms are adapted for life on

land. Water needed for nutrition only – not for

reproduction. Pollen can “fly”.

Gymnosperm Reproduction(Using conifers as our example) Mature conifers make both male AND female

cones. Produce two types of spores – male and

female, respectively. Male spores = pollen; these spores are

released. Female spores NOT mobile. Remain in their

cones. Fertilized by pollen that lands upon them.

Gymnosperm Reproduciton

AngiospermsFlower power, yo!

Angiosperms - Overview All produce a flower (not necessarily a

pretty one). Adapted to rely on a variety of

pollinators:1. Wind2. Insects3. Larger animals Enclose their seeds for protection (often

in a fruit).

Angiosperm classification Angiosperms are divided into two main

groups. Grouping is based on how many

cotyledons (“seed leaves”) the plant makes. These are the first leaves the plant will make.

1. Monocots produce one cotyledon.2. Dicots produce two cotyledons.

Monocot VS DicotMonocots and dicots differ with respect to other features, too. These include: Arrangement of xylem and phloem Structure of “veins” in the leaves Arrangement and structure of flowers

Monocot VS Dicot

Angiosperm Reproduction Happens through pollination (sexual). Involves male and female gametes.

The male gametes are always those that actually move from one place to another.

Angiosperm Reproduction cont’d Some angiosperms carry BOTH male

and female structures. Called monoecious plants

Angiosperm reproduction cont’d Other angiosperms only produce

structures for a single gender (only male or only female). These are called dioecious plants.

Angiosperm Reproduction cont’d

Angiosperm Reproduction cont’d Pollination leads to formation of seeds.

Seeds can spread through a few ways:1. Attaching to animals (uses hooks and

spines)2. Seed explosions3. Wind dispersal (using wings or

“parachutes”)

Angiosperm Reproduction cont’d4. Water5. Animal digestion (from eating fruit)