Lecture 1: Intro to Plants, Intro to Science

Why do we love plants? What makes them so special? Plants are:

People and Plants l We affect each other. – how? »We can’t live without them! ».». ».». »They can destroy habitat, harming our economy – invasive plants!! »We can alter the course of their evolution, through: –Gm crops, conservation genetics, selective breeding

Plants are sources of l food l paper l fibers l Medicine l Chocolate l Sugar l vanilla l cinnamon pepper wood cotton linen roses paper oxygen

THE PROCESS OF SCIENCE l The word science is derived from a Latin verb meaning “to know” »Science is a way of knowing ».».

The Process of Science: "The Scientific Method"

What’s a Scientific Question? l Scientific Questions are….

What’s a Hypothesis? l Tentative, but untested explanations »Ex. l Make predictions that can be tested »Predictions written as “If [hypothesis], then……” statements ».tree to grow taller

How do you test a Hypothesis? l Via controlled experiments or pertinent observations »All variables must be controlled l Kinds of variables: »Independent variable – »Dependent variable – »Controlled Variables - All other things (variables) that you try to hold constant

Experiments of classica l design l Individuals studied divided into two groups » Experimental group » Control group –exposed to the identical conditions as the experimental group, but not be exposed to the independent variable

l What happens if all of our experiments fail to disprove our hypothesis? l What if workers in other parts of the community, county, state, country, or world also fail to disprove your hypothesis?

Theory l We arrive at theories by scientific method

To Prove or Not to Prove l Experimentation can either support or reject a hypothesis. l Experimentation can never prove a hypothesis 100% correct. – why? l After each each experiment we need to re- evaluate our results and observations to either make changes in our hypothesis or more likely design a new experiment.

Which end of a plant is up?

Cells Tissues Organs Systems Muscle cell Muscle tissue Heart Circulatory system Parenchyma cell Dermal tissue Leaves Shoot system

Three organs: Roots, stems, leaves 1. Roots– Covered with root hairs – increased surface area for absorption

Modified Roots – Prop roots Sweet Potato – storage root Aerial strangler roots Pneumatophores Buttress roots

2. Stems/shoots l Two types of shoots 1.Vegetative – 2.Reproductive – l Two parts of stem: 1.Node – point of leaf attachment 2.Internode – stem segments between nodes

Two types of buds 1. Terminal bud – 2. Axillary buds – in angle (axil) between leaf & branch, contain meristem with potential to become a vegetative shoot. Mostly dormant. Apical dominance = -remove or depress apical bud, axillary buds begin to grow.

Modified Shoots (stems): l Stolons – l Rhizomes – l Bulbs – swollen underground shoots l Tubers – swollen rhizomes Asexual, vegetative propagation Stores food for later growth

3. Leaves – main photosynthesis organs

Modified leaves l Compound, doubly compound – why??

Modified leaves

Leaf types: Simple leaf = Compound leaf = divided into distinct units called leaflets

Four types of leaf arrangement: 1.Acaulescent – 2.Alternate – 3.Opposite – leaves borne across from each other at the same node 4.Whorled – 3 or more leaves arising from the same node.

3Each male flower part is called a stamen. The stamen is composed of: 1. Filament – 2. Anther – a collection of pollen sacs that sits on top of the filament.

Each female part is called a pistil. Pistil = the female reproductive organ, consisting of: 1. Stigma – 2. Style – 3. Ovary – the base of the pistil, contains the ovules. (Mature ovules are seeds and mature ovary is the fruit)

More terms!!! Complete flower = Incomplete flower = lacks one of the above parts

Fruit types Fruit = *the primary function of a fruit is seed dispersal