sbi3u: biology, university preparation 1.diversity of living things 2.genetic processes 3.evolution...

SBI3U: Biology, University Preparation

1. Diversity of Living Things

2. Genetic Processes

3. Evolution

4. Animals: Structure and Function (Digestive, respiratory, circulatory systems)

5. Plants: Anatomy, Growth and Function

What can you expect in this course?

• BIG IDEAS stated at the start of each unit

• Clear lesson goals at the start of EACH lesson

• Quizzes at the end of each chapter (2-3 chapters per unit)

• A lab, an assignment, and a unit test for each unit

• A Wikispaces course homepage to access ppt presentations, worksheets, links to games and sites

• Due to the condensed nature of this course (we only have 30 classes!) material will move quickly.

• In one class we will cover roughly 20 pages- worth of the text book.

• It is vital that you review notes between classes and complete assigned homework to succeed in this course

What can you expect in this course?

The Breakdown• Knowledge/Understanding 30%• Thinking/Inquiry 25%• Communication 20%• Application 25%

• Tests 30%• Assignments/projects 15%• Labs 15%• Quizzes 10%

70%

• Final Exam 30%

100%

UNIT 1. Diversity of Living Things

• BIG IDEAS:

– All living things can be classified according to their anatomical and physiological characteristics

– Human activities affect the diversity of living things in ecosystems

Biodiversity and

The Nature of Classification

Lesson 1.

Learning Goals

• Describe the nature of biological diversity and the biological species concept

• Outline some of the primary human-caused threats to Earth’s biodiversity

• Explain the principals of taxonomy and the concepts of taxonomic rank

• Construct and apply dichotomous keys for the purpose of identifying species

Biodiversity

• Biodiversity: The number and variety of species and ecosystems on Earth

• By 2010, over 1.7 million kinds of living things had been identified

• Earth may be home to as many as 15 million different kinds of living things! (So why haven’t we found them yet?)

Of all the species that have ever lived on Earth, how many are living today?

• less than 1%• 1%• 10%• 20%• 50%

0.1%, so in other words 99.9% of all species that have ever lived are extinct!

Greatest Mysteries: How Many Species Exist on Earth?

What is a Species?

• A species is a group whose members are able to freely breed among themselves under natural conditions

• Some plants, some fungi and micro-organisms only reproduce asexually, so traditional species definition does not apply– Use set of physical characteristics (morphology) to

define them

Individual Variability • A species is composed of individuals with

different traits

• Individuals may show subtle differences…But…

• Still belong to the same species and are members of the same breeding population

• Organisms in the same species can interbreed to produce viable offspring.

• These cannot....

• Species change over time and space. They can evolve over many generations, and they can change across continents– Five Subspecies of rat snake

Diversity in Ecosystems

• Ecosystems are made up of many different species and their physical environments

• All species depend on other species for their survival:– Organisms that cannot make their own food

(heterotrophs) feed on other living or dead organsims

– Even organisms that make their own food (autotrophs) are dependent on other organisms

Diversity of Interactions

• Interdependence between species goes far beyond simple food chains and biogeochemical (?) cylces:

• Plant communities with high species diversity are better able to withstand disease, climate extremes and pests

Diversity of Habitats

• The range of physical sizes, shapes and distribution of the individuals, as well as habitats in an ecosystem are together referred to as structural diversity

• Structural diversity is critical for biodiversity because it creates microhabitats

Biodiversity at Risk• The loss of biodiversity:

– Threatens our food supply– Eliminates sources of medicines – Economic impact on tourism and forestry – Potential to disrupt biogeochemical cycles by ecosystems

(carbon, nitrogen…)

• Species extinction is a natural process. However….

• Human actions are resulting in a rapid loss of natural habitats from agriculture, forestry, urban expansion, invasive species and climate change

• Biologist E.O Wilson estimates that the current extinction rate may be 10 000 times greater than it would be without humans

The Nature of Classification

• For hundreds of years people have been trying to classify the species on our planet Earth

• There are potentially hundreds of thousands new species still waiting to be discovered

• With the discovery of new species classification of organisms is constantly being modified

• The goal is to track evolution and determine which organisms share common ancestors

• A simple system of naming organisms allows anyone in the world to discuss the same creature regardless of its common name

• For example....

• But, Carolus Linnaeus calls him....

Melanoplus femurrubrum

http://upload.wikimedia.org/wikipedia/commons/6/68/Carl_von_Linné.jpg

• Linnaeus classified organisms according to their structural similarities: this is called TAXONOMY

• Each group to which Linnaeus assigned organisms is called a TAXA (singular is TAXON)

• Modern taxonomy groups based on their evolutionary relatedness: this is called PHYLOGENY

• Organisms share common ancestry if they show similar stages of embryological development and anatomical structures.

• The 18th century Swedish naturalist Carolus Linnaeus simplified the system of naming and classifying organisms

• The system, known as binomial nomenclature is still in use today!

• What are the two parts?!

Let’s find out......

http://upload.wikimedia.org/wikipedia/commons/6/68/Carl_von_Linné.jpg

Linnean Classification

Name: Orcinus orca

• The taxon “species” is the smallest group and it contains only a single type of organism.

• The organisms in a species are most like one another

• The individuals of a species have the same body or physiological morphology.

• Archaebacteria

• Eubacteria

• Protista

• Fungi

• Plantae

• Animalia

How Many Kingdoms?

Dichotomous Keys

• Dichotomous classification keys are used to help place organisms into the appropriate classification group

• Classification keys include two choices for each characteristic

Dichotomous Key Activity

Dichotomous Keys

• Dichotomous classification keys are used to help place organisms into the appropriate classification group.

• It is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks and fish.

• These keys consist of a series of choices that lead the user to the correct name of a given item.

• “Dichotomous” means “cut into 2 parts”. Therefore, these keys always give two choices in each step.

Dichotomous Keys

When Constructing Dichotomous Keys:

• Use constant characteristics rather than variable ones.

• Use measurements rather than terms like “large” or “small”.

• Use characteristics that are generally available to the user of the key rather than seasonal characteristics or those seen only in the field.

• Make the choice a positive one – something “is” instead of “is not”.

• If possible, start both choices of a pair with the same word.

• If possible, start different pairs of choices with different words.

• There should be one less step than there are total organisms to classify.

• The first step in the key should divide the organisms in roughly half.

• Both choices of a pair should be about the same attribute.

When Using Dichotomous Keys

• Always read both choices, even if the first seems to be the logical one at first.

• Be sure you understand the meaning of the terms involved. Do not guess.

• If the choice is not clear, for whatever reason, try both divisions. If you end up with two possible answers, read descriptions of the two choices to help you decide.

• Having arrived at an answer in a key, do not accept this as absolutely reliable. Check a description of the organism to see if it agrees with the unknown specimen.

Dichotomous Keys

Example of the Graphical form

Example of the Written form