Biology

Teaching Biology at the Institute of Biology, University of the Philippines, Diliman

Ian Kendrich C. Fontanilla, M.Sc.([email protected])

Teaching Biology

• Biology is a broad topic that can easily overwhelm the teacher as much as the student

• Is biology purely memorization, or is there more?

• The students must retain the key concepts long after they’ve forgotten many facts and terms

• Students should relate biological concepts to everyday life

Our Teaching Experience in IB

• We rely heavily now on the LCD projector and our powerpoint presentations with clearer figures

• ..but we never abandon the chalk and board to stress points!


• Hands on experience through lab exercises is still indispensible


• …as well as field work!

Some Examples of Biological Concepts and How They are Taught

1. Bioinformatics

2. Biogeography

What is bioinformatics?

• Application of computers, databases, and computational methods to the management of biological information

• Biological information can be in the form of:

• Nucleotide sequences (DNA and RNA)

• Amino acid sequences and protein structure

• Gene expression


• Biological database

• A large, organized body of persistent data, usually associated with computerized software designed to update, query, and retrieve components of the data stored within the system

• Biological information are stored in biological databases in order to organise the data on a large scale

• Must be easily accessible

• E.g. GenBank (www.ncbi.nlm.nih.gov)

Molecular Phylogeny – an application of bioinformatics

•Estimating and analyzing evolutionary relationships using molecular markers such as DNA and proteins

•Molecular markers retain a record of an organism’s evolutionary history

•The nucleotide or amino acid differences within a gene reflect the evolutionary distance between two organisms

•Molecular markers are easily quantifiable compared to morphological data


• There has been a phenomenal increase of biological information (e.g. molecular biology) in the last few decades

• e.g. GENBANK – definitive database in the US for gene sequences

• (http://www.ncbi.nlm.nih.gov)

•Makes use of the freeware BioEdit (www.mbio.ncsu.edu/BioEdit/BioEdit.html)

•Neighbor-joining phylogenetic tree of mammals based on the mbrca1 gene

•Deals with geographic patterns of species distribution and

the processes that result in such patterns.

•Species distribution brought about by several factors:

•speciation

•extinction

•continental drift

•glaciation

Biogeography

SE Asia Reconstructions

50-0 Ma

© Robert Hall 1995

50

40

20

10

0

Islands of the Philippines during the last ice age (~10,000 years ago)

Some Examples of Problematic Biological Concepts

and How We Teach Them in IB

1. The theory of evolution

2. The issue on reproductive health

•“It’s just a theory.”

•Should contraception be taught in the first place?

•Should contraception be taught in grade school and

high school?

1. Evolution

•Change in gene frequencies in populations over time

•Unifying concept in biology

•“Nothing in biology makes sense except in the light of evolution.”

(Theodosius Dobzhansky: 1900-1975)

•Explains:

•Origin of species

•Diversity of organisms and their relationships

•Similarities and differences among species

•Adaptations to the environment

Evolution – how we teach it in IB

•Evolution IS a theory that is testable

•We lay out all the facts

•Ask the students to critically analyse the facts

•What are their conclusions about evolution?

1. Young Earth Creationists

• accept Genesis literally, including not just the

special, separate creation of human beings and all

other species, but the historicity of Noah’s Flood

• do not interpret the flat-earth and geocentric passages

of the Bible literally, but they reject modern physics,

chemistry, and geology concerning the age of the

earth

Different reactions to evolution

2. Day-Age Theorists

• each of the six days of creation is not a 24-h day but a

long period of time, even thousands or millions of

years

• found comfort in what they regard as a rough parallel

between organic evolution and Genesis, in which

plants appear before animals and human beings

appear last


• God created kinds of animals that were of a higher

taxonomic level than species

• God created creatures containing at least as much

genetic variation as a family (e.g. Felidae,

Cercopithecidae) and considerable evolution within a

kind then occurred

3. Progressive Creationists


• certain features of the universe and of living things are

best explained by an intelligent cause, not an undirected

process such as natural selection

• argue that an archaeologist who finds a statue made of

stone in a field may justifiably conclude that the statue

was designed, and reasonably seek to identify its

designer

4. Intelligent Design Proponents


• God created but relied more upon the laws of nature to

bring about His purpose

• see God as intervening at critical intervals during the

history of life especially in the origin of human beings

5. Theistic Evolutionists

• one species can give rise to another


• go beyond science and propose that the laws of nature

are not only sufficient to explain all of nature and

evolution but that the supernatural does not exist

• philosophical materialism (naturalism) there is

nothing in the universe beyond matter, energy, and

their interactions

6. Material Evolutionists


2. The Reproductive Health

• A right that should be accorded every woman

• “involves the right to decide freely and responsibly the

number and spacing of children and to have information,

education and means to do so”

• Panao, 2008

• When does life begin?

Implantation

•Egg moves along oviduct to uterus

•6th day after fertilization, blastocyst attaches to uterine wall or ENDOMETRIUM

• Stage after fertilization in humans where a blastocyst develops from a fertilized zygote

Human Embryonic & Fetal Development

•Human gestation time – from conception to birth – approximately 9 months

•Embryonic development – months 1 – 2

•Fetal development – months 3 – 9

Contraceptives

Blocks any one of the following stages of early development:

1. Release & transport of gametes

2. Fertilization

3. Implantation

Types of Contraceptives

1. Ovulation-suppressing methods

2. Barrier methods (physical and chemical)

3. Surgical methods

4. Implantation-suppressing methods

5. Others

Reproductive Health – how we teach it in IB

•Explain human development from gametes to adulthood

•How is development stopped by each type of contraceptive

•Ask the students when they think life should begin

•Ask the students if they would use contraceptives

Documents

Biology