Biodiversity Quiz 4

Gymnosperms

naked seeds, seed does NOT develop in enclosed structure

Angiophyta (Angiosperms / flowers)

seed vessel, seed develops inside carpel (protective structure), over 250,000 known species, eg. oak trees, thrive environments from desert to freshwater to rain forests, defining adaptation: flowers, vascular tissues have both tracheids and vessel elements, have ovules, supply food that supports all organisms.

Diversification of Flower

appeared 150 mya

Flower

reproductive organ that allowed mass diversification of angiosperms, contain stamens and carpels, heterospory is similar to gymnosperms except for double fertilization,

Anther

microsporangia

ovary

macrosporangia and eggs

Double Fertilization

one sperm cells fuses with egg to form zygote, second sperm fuses with 2 nuclei in female gametophyte (made of 7 cells, one of her cells have 2 nuclei) to form a tripoloid (3n) endosperm

endosperm

nutritive tissue result of double fertilization

Angiosperm Life Cycle

Pollination

stamens and carpels enclosed with sepals and petals, 4 structures diversified to produce diff sizes, shapes, colors, and smells, increases probability for pollination

pollination

transfer of pollen from one flower’s stamen to another’s carpel

Directed Pollination Hypothesis

natural selection favors flower colors, shapes, and scents that are successful in attracting particular types of pollinators, provide pollinators with food, mutually beneficial relationship

Evidence Supporting DPH

scent: carrion produces rotting flesh smell that attracts carrion flies

Shape: humming-bird pollinated flowers have adapted a long flower petal shaped for the birds'' beak shape

Color: adapt color best seen by pollinator

Expirement: altering length of spur in different orchids

Fruits

structure that is derived from the ovary and encloses 1+ seeds, mature ovaries that ripen, when pollinated: ovules emit hormones, ovary of fruit develops into pericarp

Fruit Development

fertilization initiates fruit development but also seed and embryo development, 3 basic fruits: Simple, Aggregate, and multiple

Simple Fruits

eg: apricot

develop from single flower that contains 1 carpels that are fused together

Agregate Fruits

eg: raspberry

develop from single flower but contain many separate carpels

Multiple Fruits

eg: pineapple

develop from many flowers thus many carpels

Seed Dispersal

wind, water, or animals.

Other method: Ballistic, Water, Animal Feet/Legs

Ballistic

Shoot seeds via water system

Seed Germination

only germinates in right conditions: right aount of light, water, temp, and O2

3 ways to germinate: Scarification, Stratification, Double Dormancy

Scarification

go through digestive track of animal

Stratification

need to be kept at temp less than 45 degrees

Double Dormancy

rely on both scarification and stratification

Angiosperm Radiation

3 key adaptation: Vessel Elements, Flowers, and Fruits

Divided into 2 major groups based on cotyledons (first leaves): Monocotyledons and Dicotyledons

Monocotyledons (Monocots)

monophyletic, have 1 cotyledon, scattered vascular tissue throughout stem, parallel veins, petals in mult. of 3

Dicotyledons (Dicots)

paraphyletic

Also called Eudicots

Eudicots

subset of dicots that represent monophyletic group, 2 cotyledons, vascular tissue arranged in circle in stems, branching veins, petals in mult. of 4-5

Angiosperm Phylogeny

Monocot VS Dicot Characteristics

5 Derived Traits of Seed Plants