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Lecture 1: Intro to Plants, Intro to Science. Why do we love plants? What makes them so special?. Plants are:. People and Plants. We affect each other. – how? We can’t live without them! . . They can destroy habitat, harming our economy – invasive plants!!
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Why do we love plants? What makes them so special? Plants are:
People and Plants • 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 • food • paper • fibers • Medicine • Chocolate • Sugar • vanilla • cinnamon • pepper • wood • cotton • linen • roses • paper • oxygen
THE PROCESS OF SCIENCE • The word science is derived from a Latin verb meaning “to know” • Science is a way of knowing • .
What’s a Scientific Question? • Scientific Questions are….
What’s a Hypothesis? • Tentative, but untested explanations • Ex. • Make predictions that can be tested • Predictions written as “If [hypothesis], then……” statements • .tree to grow taller
How do you test a Hypothesis? • Via controlled experiments or pertinent observations • All variables must be controlled • Kinds of variables: • Independent variable – • Dependent variable – • Controlled Variables - All other things (variables) that you try to hold constant
Experiments of classical design • Individuals studied divided into two groups • Experimental group • Control group • exposed to theidentical conditions as the experimental group, but not be exposed to the independent variable
What happens if all of our experiments fail to disprove our hypothesis? • What if workers in other parts of the community, county, state, country, or world also fail to disprove your hypothesis?
Theory • We arrive at theories by scientific method
To Prove or Not to Prove • Experimentation can either support or reject a hypothesis. • Experimentation can never prove a hypothesis 100% correct. – why? • 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.
Muscle cell Parenchyma cell Cells Tissues Muscle tissue Dermal tissue Organs Heart Leaves Circulatory system Systems Shoot system
Three organs: Roots, stems, leaves • Roots– • Covered with root hairs – increased surface area for absorption
Sweet Potato – storage root Modified Roots – Prop roots Aerial strangler roots Buttress roots Pneumatophores
2. Stems/shoots • Two types of shoots • Vegetative – • Reproductive – • Two parts of stem: • Node – point of leaf attachment • Internode – stem segments between nodes
Two types of buds • Terminal bud – • 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): • Stolons – • Rhizomes – • Bulbs – swollen underground shoots • Tubers – swollen rhizomes Asexual, vegetative propagation Stores food for later growth
3. Leaves – main photosynthesis organs http://www.knotweed.co.uk/japknot_Info.htm
Modified leaves • Compound, doubly compound – why??
Leaf types: Simple leaf = Compound leaf = divided into distinct units called leaflets
Four types of leaf arrangement: • Acaulescent – • Alternate – • Opposite – leaves borne across from each other at the same node • 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