Plants, Insects and our Environment and How They Interact!!!!

Photosynthesis Photosynthesis:

Process by which plants capture Energy from the Sun; use it to build Carbohydrates Directly by eating the plant (lettuce) or indirectly (by eating another animal), they

provide the food for the living world, including themselves Occurs in plants, algae, certain other protists, and some prokaryotes

Oxygenic Photosynthesis: Produces oxygen; cyanobacteria, algae and essentially all land plants

(a) Plants(b) Multicellular

alga

(c) Unicellularprotists

(d) Cyanobacteria

(e) Purple sulfurbacteria

10 m

1 m

40 m

Figure 10.2

Algal Groups – Green, Brown and Red

Non – Vascular Plants - Mosses

Number of Land Plant Species

Seedless Vascular Plants - Ferns

Carboniferous Plants – Coal Formation

Seeds: Transforming the World Seed:

Consists of an embryo and nutrients surrounded by a protective coat

Seeds: Changed the course of plant evolution, enabling

them to become the most Dominant Photosynthetic Producer in most terrestrial ecosystems

Seed Plants: Plants and other organisms were able to move on

land because of the formation of the ozone layer Originated about 360 million years ago Domestication of seed plants along with animals

had begun by 8,000 years ago and allowed for permanent settlements

Seed Plants

Seeds provide some evolutionary advantages over Spores Producers (Ferns): May remain dormant for years until conditions are favorable for germination Have a supply of stored food – good for the plants but “Food for Us” My be transported long distances by wind or animals or water

Gymnosperms: “Naked Seeds” Seeds are exposed on cones Appear early in the fossil record about 305 million years ago and dominated Mesozoic (251–

65 million years ago) terrestrial ecosystems Today, cone-bearing Conifers dominate in the northern latitude

Angiosperm: Seeds are found in fruits, which are mature ovaries Began to replace gymnosperms near the end of the Mesozoic Dominate more terrestrial ecosystems

Gymnosperms – Cycads Cycads:

Most are tropical or subtropical with palm-like leaves Individuals have large cones (either male or female) Air or Beetles carry pollen Thrived during the Mesozoic, but relatively few species exist today

Gymnosperms – Ginkgo Ginkgo:

Age of the Dinosaurs Single living species, Ginkgo biloba Male is widely planted Pollinated by wind Leaves are resistant to insects, disease and

air pollution

Gymnosperms – Gnetophyta Gnetophyta:

Genera: Gnetum, Ephedra, Welwitschia Species vary in appearance Some are tropical; others live in

deserts having a deep tap root

Gymnosperms – Conifers

Conifers: Largest group of the Gymnosperms Many dominant the forested regions of the Northern Hemisphere Most conifers are evergreens; few are deciduous Evergreens can carry out photosynthesis year round as they retain their leaves Tallest – redwood; oldest – bristlepine cone

Life Cycle - Reproduction: Development of Seeds from fertilized ovules Transfer of sperm to ovules by Wind Blown Pollen

Figure 30.5e

Douglas fir

Common juniper

European larch

Sequoia

Wollemi pine Bristlecone pine

Angiosperms

Angiosperms: Ancestors of Angiosperms and Gymnosperms diverged 305 million years ago Angiosperms originated at least 140 million years ago Comprise more than 250,000 living species

Previously, Angiosperms were divided into 2 main groups; Monocots (one cotyledon) – remain as a group Dicots (two dicots)

Today, Eudicot (“True” Dicots) includes most Dicots

Angiosperms – Basal Basal Angiosperms:

3 small lineages: Amborella trichopoda, water lilies, and star anise

Angiosperms – Magnoliids Magnoliids:

Include magnolias, laurels, and black pepper plants More closely related to monocots and eudicots than basal angiosperms

Angiosperms – Monocots Monocots: > 25% angiosperm species are Monocots

Angiosperms – Eudicots Eudicots: > 2/3 angiosperm species are Eudicots

Angiosperms Angiosperms: Greek anthos for flower

Seed plants with reproductive structures called Flowers and Fruits Pollinators: animals (insects that feed on pollen) move pollen grains from male parts of

one flower to female parts of another Coevolution: over time, plants and animal pollinators jointly evolved; changes in one

exerts selection pressure on the other

Angiosperms have 2 key adaptations Flower:

Structure specialized for sexual reproduction Pollinated by insects, animals or wind

Fruits: Typically consists of a mature ovary but can also include other flower parts Protect seeds and aid in their dispersal

Seeds can be carried by Wind, Water, or Animals to new locations

Angiosperm Flowers Flowers are the Reproductive Structure of Angiosperms:

Non-Reproductive: Corolla (Petals): leaflike ring (brightly colored) that attracts pollinators Calyx (Sepal): leaf-like outer whorl at base; photosynthetic; protects ovary Receptacle: modified green base of the flower (modified leaves)

Reproductive: Stamens: male parts of a flower

Anther: pollen is produced by meiosis in pollen sacs Filament: veined stalk that holds the anther

Carpels (Pistils): female parts of a flower Ovary: eggs developed Style: tube that connects the ovary with stigma Stigma: sticky or hairy surface where the pollen lands

Figure 38.2a

StamenAnther

Filament

Petal

Receptacle

StigmaStyle

Ovary

Carpel

Sepal

(a) Structure of an idealized flower

Diversity of Flowers Flower Structure: adaptations to maximize Cross-Pollination between 2 different plants

Regular: symmetric (identical sections) or Irregular: not radially symmetric flowers Single: 1 flower or Inflorescences: many flowers

Complete: sepals, petals, stamens and carpals Incomplete: lack one or more of these structures

Perfect: may be pollinated by other plants or itself Imperfect: male or female parts or cannot be pollinated by itself

Monoecious: both male and female Diecious: male or female flowers on separate plants

Self-Pollination has its advantages but often produces plants that are less vigorous than Cross-Pollinated Plants

Pollination About 390 mil years ago, Seed Plants began making Pollen – at 1st, air currants may have disperse

the pollen but Insects made the connection between “Plant with Pollen” and “Food”

Pollination: Transfer of Pollen from an anther to a stigma by wind, water, or animals Wind-Pollinated species (grasses and many trees) release large amounts of Pollen

Co-Evolution: 2 or more species jointly evolving as an outcomes of close biological interactions Heritable changes in one species affects the other so the other evolves also

Pollination Vectors: Agents that deliver pollen from an anther to a compatible stigma (wind or releasing billions

of pollen grains)

Pollinators: Living pollination vectors (insects, birds, or other animals) Flower shape, pattern, color and fragrance are adaptations that attract sanimal pollinators Often rewarded for visiting a flower by obtaining nutritious pollen or sweet Nectar Selective advantage of Pollinators visiting flowers - bring the pollen to the next plant 90% of the 295,000 have Co-Evolved with Pollinators and do not depend on the Wind

Pollinators Visual Cues:

Bee pollinated flowers are often yellow, blue or purple Birds and butterflies are attracted to red and yellow flowers

Olfactory Cues: Bats (nectar sipping) search for intense fruity or musty odors Beetles and flies search for fermenting fruit and drug

Nectar: Sucrose rich fluid secreted by the plant Provides the food for butterflies and hummingbirds Bees collect it and bring it back to the hive to make Honey

Flowers: Evolved with their Pollinator Nectar rich floral tubes are the same length as the pollinator’s feeding siphon (proboscis) Small flowers like daisies are of no interest to finches or bats Tall, thin flowers cannot support beetles

Angiosperms and Their Pollinators

Abiotic Pollination by Wind Pollination by Bees

Hazel staminate flowers(stamens only)

Hazel carpellateflower (carpels only)

Common dandelionunder normal light

Common dandelionunder ultraviolet light

Figure 38.4a

Pollination by Mothsand Butterflies

Blowfly on carrionflower

Pollination by Flies Pollination by Bats

Moth on yucca flower Long-nosed bat feedingon cactus flower at night

Hummingbirddrinking nectar ofcolumbine flower

Pollination by Birds

Stigma

Anther

Moth

Fly egg

Figure 38.4b

Corpse Flower

Apple and Peach Flowers

Cactus Flowers

Hummingbirds and Flowers

Fruits Fruit:

Develops from the Ovary Protects the enclosed seeds and aids in seed dispersal by wind or animals May be classified as Dry, if the ovary dries out at maturity, or Fleshy, if the ovary becomes

thick, soft, and sweet at maturity

Fruits are also classified by their development: Simple: single or several fused carpels Aggregate: single flower with multiple separate carpels Multiple: group of flowers called an inflorescence Accessory: other floral parts contribute to the fruit; apple, ovary is embedded in the

receptacle

Fruit Dispersal Mechanisms include: water, wind and animals

Figure 38.10

Stamen Ovary

StigmaOvule

Pea flower

Seed

Pea fruit(a) Simple fruit (b) Aggregate fruit (c) Multiple fruit (d) Accessory fruit

Carpels Stamen

Raspberry flower

Carpel(fruitlet) Stigma

Ovary

Stamen

Raspberry fruit

Flower

Pineappleinflorescence

Each segmentdevelopsfrom thecarpelof oneflower

Pineapple fruit

StigmaPetal

Style

StamenSepalOvule

Ovary (inreceptacle)

Apple flower

Remains ofstamens and styles

Sepals

SeedReceptacle

Apple fruit

Seeds

Seed (mature ovule): Embryo and nutritious endosperm encased in a seed coat Remains dormant until conditions are right for germination and growth resumes

Germination: Process by which a dormant mature Embryo in a seed resumes growth after a period

of arrested growth (Dormancy) Begins when water activates enzymes in the seed Cell divide, elongate and differentiate into primary root Ends when the Primary Root breaks the seed coat

Growth: Differentiation results in the formation of tissues and parts in predictable patterns Cells divide by Mitosis

Dispersal by Wind

Dandelion “seeds” (actually one-seeded fruits)

Winged fruit of a maple

Dandelion fruitTumbleweed

Dispersal by Water

Winged seed ofthe tropical Asian

climbing gourdAlsomitra macrocarpa

Coconut seed embryo,endosperm, and endocarp

inside buoyant husk

Figure 38.11a

Figure 38.11b

Dispersal by Animals Fruit of puncture vine(Tribulus terrestris)

Squirrel hoardingseeds or fruitsunderground

Ant carryingseed with nutritious“food body” to itsnest

Seeds dispersed in black bear feces

Fruit and Seed Dispersal

Asexual Reproduction Many Angiosperm species reproduce both Asexually and Sexually

Asexual Reproduction results in a clone of genetically identical organisms In some species, a parent plant’s root system gives rise to adventitious shoots that become

separate shoot systems

Bees as Pollinators in Our Food Supply