Themes of Biology
Purvi Trivedi
4 Key Themes of
Biology
What is Biology?
1 min
5 mins
Properties of Life
18 mins
Explain Homework :)
5 mins
Emphasis on Evolution
1 mins
What is Biology?
❖
Biology is the scientific study of life
❖
Biologists ask questions about the
natural world
❖
Ongoing inquiry about nature of life
▼Order
What is life?
Properties of Life
Q: What are some
characteristics of
living things that you
can think of?
▲ evolutionary
adaptation
▲regulation
▼reproduction
▲ energy
processing
▲response to
environment
▲ growth & development
5 Unifying
Themes of
Biology
1. Organization
2. Information
3. Energy & Matter
❖
❖
Biology involves connecting the
dots between different fields
Themes help organize biological
info across a broad range of
topics
4. Interactions
5. Evolution
1. Organization
1
Biosphere
2
Communities
Ecosystems
3
4
Populations
▲5
Organisms
▼6
Organs
7
Tissues
▼10
Molecules
Basic unit
of
structure
and
function
▼9 Organelles
▲8 Cells
2. Information
DNA= genetic material
Genes= unit of inheritance
❖
DNA = deoxyribonucleic acid
❖
❖
Double stranded helix
➢ Each chain made up of four
nucleotides A, C, T, G
Control protein
production indirectly
❖
Gene expression=
process of converting
info from gene to
cellular product
❖
Heritable
❖
Stored in chromosomes in
nucleus (eukaryotes) or nucleoid
(prokaryotes)
❖
Blueprint for proteins (think
“template”)
➢ DNA is transcribed
to RNA
➢ RNA is than
translated to
protein
3. Energy & Matter
❖
Organisms use energy to carry
out work
❖
Energy is transformed
➢
Producers use chemicals to convert
solar energy (photon) to chemical
energy (food) via photosynthesis
➢
Consumers feed on other
organisms
❖
❖
Uni-directional flow of energy:
enters as light, exists as heat
Cyclic flow of chemicals/matter:
used and recycled between
organisms and environment
4. Interactions
From molecular level to ecosystem level,
interactions occur in every biological
hierarchy
❖
❖
Molecular level: feedback regulation
➢
Negative feedback: glucose levels
➢
Positive feedback: blood clots
Ecosystem level: continuous interactions
➢
organism-organism (ex. mutualism,
parasitism)
➢
organism-environment (ex. photosynthesis;
humans inducing global warming)
5. Evolution: Core Theme of Biology
❖
Explains the unity & diversity
of life, as well as adaptation
of organisms to their
environments
❖
~1.9M species named so far
out of predicted 10-100M
❖
Binomial nomenclature:
➢
➢
❖
[Genus] [species] or [G.] [species]
Ex. Homo sapiens or H. sapiens
Three domains attempt to
make sense of broad scope
of biological variety
Natural Selection:
Key Principle of
Evolution
❖
Proposed by Charles Darwin in 1859
as the mechanism for evolutionary
adaptation of populations
❖
Occurs when population is exposed to
environmental factors that
consistently cause individuals with
certain heritable traits to have greater
reproductive success than individuals
with other heritable traits
Example of Natural Selection
Beetles
Light gray
or charcoal
Population evolves over
time!!
Darker beetles survive
to reproduce, reducing
variation of color by
increasing frequency
of darker coloration
Many beetles
Fire causes soil
to darken
Lighter beetles get
eaten more because
easier to spot
Key Takeaways:
❖
Biology is an ongoing inquiry about
nature of life
➢
❖
scientists are constantly discovering new
info and adjusting current findings
The five themes help connect the
vast topics of biology:
➢
➢
➢
➢
➢
Organization
Information
Energy & Matter
Interactions
Evolution→ the core theme
❖
❖
The cell is the basic unit of life
Cells use energy to perform
work
❖ DNA is the universal genetic
material, and is heritable
❖ Interactions occur in every
organizational level (molecular
to ecosystem)
❖ Evolution occurs at the
population level and happens
over time
Homework!!
❖ Ordering organizational levels
❖ True/False questions
❖ Critical thinking: requires outdoor
time :)
❖ Please write your name and the
date on the upper right corner
Source for figures: Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V.,
Reece, J. B., & Campbell, N. A. (2017). Campbell biology (Eleventh edition). Pearson
Education, Inc.