Ecology: Study of interaction between the organisms and it’s environment

Dispersal of seeds by animals

Fruits of persimmon tree

Habitat: Place where an organism live

• Abiotic

• Biotic

• Limiting factor

Plants are indictors of their environment

Plants are adapted to it’s environment

Adaptation:

Opuntia (Cactaceae:cholla cactus)

Guerrero, Mexico

Dispersal of fruits and seed reduces predation and competition

OvaryOvules Impatiens glandulifera

Touch-me-not

Some seeds are dispersed by wind and water

The seeds of most Asclepias(Asclepiadaceae:milkweed) species produce a coma of hairs that aid in wind dispersal

Coconut (Cocos nucifera) Fruits may float in the oceans for weeks before reaching a beach for germination

Germination and Growth of plant depends on favorable environmental conditions

• Seed Dormancy (water, temperature and light)

• Stratification (apple tree and most pines)

• Scarification (legumes – hard seed coat)

• Desert seed- Safeguard against premature germination

- Germination inhibitors

Seed Bank (Seeds may lie dormant in soil for many years

• Pumpkins , squash, etc (several years)

•Arctic tundra lupine (Lupinus arcticus) 10,000 years!

Plants maintain balance between root and shoot system

•Leaves provide ecological trade-off in a plant

Hair on leaves•Photosynthesis

• Transpiration

Geranium

• Intake of Co2 and loss of H20 through stomata

Balance between shoot and root system

Weed control by herbicide 2,4-D

Wilting of plants

• Population

• Community

• Ecosystem

• Plants are the Producers

• Herbivores and carnivores are Consumers

• Bacteria and fungi are Decomposers

FOOD CHAIN

Cobra lily (Darlingtonia californica)

ADAPTATION

Habitat: Northern California/Oregon

Evolution of plants with other species in ecosystems

• Competition – Sunlight: tall, leaf orientation, chlorophyll content

Parthenocissus tricuspidata

Plants/Herbivores Interactions

Plants Spines• Volatile oils by mint family (Lamiaceae)

•

Insects • Enzymes that breakdown chemicals• Stimulate growth/eg. mowing grass

Anise swallowtail butterfly

Feeds on parsley family(Apiaceae)

Parasite/host Interactions

Mistletoes, like Phoradendron juniperianum (Viscaceae) are greenish, but do not photosynthesize, gaining nutrition by parasitizing their host

Parasite/host InteractionsWheat Stripe Rust (caused by fungus Puccinia striiformis)

Mutualistics

Plant/insect pollination Pacific bleeding heart

(Dicentra formosa)

Natural Selection

• Individuals best adapted to their environment produce most offspring's and pass their genes to the next generation

Charles DarwinBritish Naturalist

1809 -1882

I have called this principle, by whicheach slight variation, if useful, is preserved,

by the term Natural Selection.—Charles Darwin from "The

Origin of Species"

Principles of Natural Selection

1. Organisms have a tendency to produce more offspring than survive.

2. Only the fraction of the offspring in a population live to produce offspring.

3. Individuals in a population vary, and these variations are inherited (at least in part) by their offspring.

4. Individuals with favorable traits produce, on average more offspring that survive to reproduce, than those with unfavorable traits

3. Individuals in a population vary, and these variations are inherited (at least in part) by their offspring.

Artificial Selection (1896)

Morrow Plots: Oldest corn research station in the world

Average Protein Content: 10.9%

The Low Protein is down to: 4.9%

The High protein is up to: 19.4%

• Natural selection is meaningful in context to the environment

• Struggle for existence/Survival of the fittest

• Natural selection is a driving force for evolution