Download Bio101 Topic 1-2

Principles of Biology
BIO 101
Dr. Rosa Gambier
[email protected]
Office: Lindsay Room 304
Introduction
Why Study Biology???
•It’s EVERYWHERE!
Why Study Biology?
Biology frequently plays a role in dealing with
various challenges that face society
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Biology helps us answer questions
about facts of life
Biology is the study of Life (Bios = life,
logos=knowledge)
• Plant Biology or Botany is the part of
Biology that studies plants.
•Zoology (Zoo= animal) is the part of
Biology that studies animals.
•Microbiology is the area of Biology that
studies microorganisms.
What is life?
There is not an agreed definition, but all living
things share these 6 features
Living things…
1. Are organized: They
maintain stable chemical
composition.
Biosphere
Ecosystem
Florida coast
Level
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Nerve
Organ system
Nervous system
Brain
Organ
Brain
Tissue
Nervous tissue
Cell
Nerve cell
• Ecosystem
• Community
• Population
• Organisms
• Systems
• Organs
• Tissues
Atom
Nucleus
Organelle
Nucleus
Molecule
DNA
Hierarchy
of Life
• Cells
• Molecules
• Atoms
 Atoms
 Molecules
 Cells
 Tissues
 Organs
 Systems
 Organism
 Population
 Community
 Ecosystem
From the
smallest
to the
largest
Levels of Organization
Atom
Carbon C
Nitrogen N
Hydrogen H
Oxygen O
Sulfur S
Phosphorus P
Molecule
H2O
DNA
Cell
Single Cell
organisms or
multicellular.
Prokaryotic Cells:
Cells
without a nucleus
Eukaryotic Cells: Cells with a nucleus
Unicellular vs. Multicellular
• Single Cell or unicellular: The entire individual is made of a single cell.
• The cell can be prokaryote (cells that lack a nucleus), for example all
the bacteria.
• The cell can eukaryotic (cells with a membrane bound nucleus and
membrane bound organelles), for example most organisms of the
Kingdom Protista such as Euglena, Paramecium and Amoebas.
• Multicellular organism: Organisms made of two or more cells.
Multicellular organisms can only be made of eukaryotic cells.
The path to multicellularity
Levels of Organization
Atom
Carbon C
Nitrogen N
Hydrogen H
Oxygen O
Sulfur S
Phosphorus P
Molecule
H2O
DNA
Cell
Tissue
Single Cell
organisms or
multicellular.
Muscle,
cartilage,
bone,
nervous,
dermal, etc.
Blood
Tissues
Tissues: A tissue is an ensemble of
identical or different cells from the same
origin that together carry out a specific
function. Name examples!
Example of tissue
• Blood is a tissue.
• The function of blood is to transport.
• Blood is composed of two types of cells
• Red Blood Cells
• White Blood cells (5 different types)
• And
• Platelets
• Plasma
•The red blood cells
Transport
oxygen (O2)
and
carbon dioxide
(CO2)
•The white blood cells
Transport
immune
factors such
as
antibodies,
histamines,
etc.
•Platelets
Transport
clotting
factors
•Plasma (liquid fraction)
Transport
nutrients
2. All living organisms metabolize
• Metabolism is management of energy.
ability to produce work).
(Energy is the
• Management of energy means that organisms obtain and
use energy.
• Living organisms take energy from environment, transform
it & use it. They use the energy to grow and develop.
• Autotrophs: Transform energy from the environment. i.e.
plants.
• Heterotrophs: Ingest their energy in the form of food. i.e.
humans.
Autotrophs:
Photosynthesis
Heterotrophs:
Herbivores
Carnivores
Omnivores.
Sun
Inflow
of
light
energy
Loss
of
heat
energy
Air
Chemical
energy
Organisms
Soil
Cycling
of
chemical
nutrients
ECOSYSTEM
Metabolism: Energy flows from one trophic level into
another, creating and connecting food networks.
3. All living organisms reproduce
Living organisms have developed several
modes of reproduction including sexual or
asexual, or both.
Both modes of reproduction have advantages and
disadvantages:
Asexual Reproduction.
• All the offspring are identical to the parent. Asexual
reproduction does not require time and energy to
be spent on seeking a receptive mate. Asexual
reproduction is sometimes known as cloning.
• Asexual reproduction does not involve the process
of meiosis and fertilization, hence the process does
not require a mate for reproduction.
• This type of reproduction is seen in lower forms of
organisms.
Advantages
• This type of reproduction enable organisms to reproduce
without a mate. It does not require the time and energy
that takes to search a mate.
• It results in the reproduction of large number of offspring
rapidly.
• Like in plants, it enables to spread and colonize an area in
short period of time.
• Stable environments with very little change are favorable
for organisms to reproduce asexually.
Disadvantages
• In this type of reproduction the offspring produced are
genetically identical to each other and to the parent. This
causes no or very little genetic variation within a
population.
• Any mutation in the parent cell, can cause harmful effects
on the survival ability of the offspring.
• Environment changes could be deadly to all the
individuals.
Sexual Reproduction.
• In sexual reproduction the offspring, although similar to their
parents, are not identical to them or to one another. This is
because the offspring receive some genes from the mother
and some from the father. Because of the mixing of genes of
mother and father in various different combinations, all the
offspring have genetic variations.
• Sexual reproduction requires time and energy to be spent on
seeking a receptive mate.
• Sexual reproduction involves the process of meiosis and
fertilization, hence the process involves Meiosis, during the
formation of reproductive cells securing the production of
genetically different gametes (crossing over and Independent
assortment and random fusion of gametes during
fertilization)
Advantages of Sexual Reproduction
• Sexual reproduction leads to a greater variety in population.
• Sexually reproduced organisms with a larger genetic variety
can adapt more quickly to changes in its surroundings (or
environment). This is because there are always likely to be
some individuals who are more suited to the changes than
others, and these individuals will survive and reproduce
themselves. Offspring are genetically unique from:
• Favorable when the environment is not stable.
• Slower rate of reproduction but faster evolution.
• Lower extinction rates.
• Fast removal of bad mutations or can put two beneficial
mutations together.
• Offspring are dispersed widely to end up in different places
from their parents.
4. Living Organisms Interact with their
environment
• Living organisms respond to different stimuli for different
reasons. It may include the need to obtain food, its reproduction
or responses to physical conditions it uses to survive.
• For example the simple exchange of gases in plants or the
complicated behavioral response involved in predation.
The three major types of interactions among organisms are:
•Competition
•Predation
•Symbiosis
Environmental interaction
A Venus
flytrap
responds to
the stimulus of
a dragonfly
landing on it
A web of
interactions in a
rain forest
ecosystem
5. All living organisms evolve.
 All living things evolve
 Evolution is a gradual change over a long period
of time (most of the time!)
 Evolution explains the diversity and adaptations
of life
 Evolution is the change in genetic material of a
population of organisms from one generation to
the next (we’ll come back to this). This is based
on sexual reproduction.

Living organisms show variations based on heredity.

These variations allow them to adapt to their
environments and ways of life.

The theory of natural selection explains the main
mechanism whereby all species of organisms change,
or evolve.
6. All living organisms have DNA as their
genetic blueprint
• Living Things Use DNA to
Store Genetic Information.
6. All living organisms have DNA as their
genetic blueprint
•For example. This photograph shows some of the
the variety possible within one species.
•Even, when the orchids look similar, each species
has its own DNA sequence
•At the same time, this photograph shows the
opposite. A series of different species of orchids.
Even though they share several similarities, they
have acquired sufficient DNA differences that are
different species (they cannot interbreed).
•Even, when the orchids look similar, each species
has its own unique DNA sequence
What is biodiversity?
•The term biodiversity refers to the variety of life on
Earth at all its levels, from genes to ecosystems, and
the ecological and evolutionary processes that
sustain it.
•In order to study biodiversity, scientists classify
organisms into a hierarchy of groups.
•Grouping organisms by fundamental features helps
make the vast diversity of life manageable for study
All organisms are grouped into three DOMAINS
• Domain Archaea
• Domain Bacteria
• Domain Eukarya:
Protistans, Fungi,
Plants and Animals
The domain Eukarya is classified into four
KINGDOMS
Kingdom Protista: Single cells
organisms, including algae.
Kingdom Fungi: Includes mushrooms,
mildews, yeasts and molds.
Kingdom Plantae:
Multicellular autotroph
organisms.
Kingdom Animalia:
Multicellular heterotroph
organisms.
Classification
•Domains are further classified/categorized
into:
•Kingdom
•Phylum
•Class
•Order
•Family
•Genus
•Species
Domain
Kingdom
Phylum
Subphylum
Class
Order
Family
Diversification
Genus
Species
What is a species?
Species: a set of individuals that are closely
related by descent from a common
ancestor and ordinarily can reproduce
with each other, but not with members of
any other species.
Biological species: group of interbreeding
populations. Offspring are fertile.
Biological species concept
• Humans may have
considerable diversity, but we
all belong to the same species
because of our ability to
interbreed
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Homo sapiens
Species name
• Each species has a single correct scientific name (called a
binomial or two names). It is written in and it is always
italicized or underlined.
•First name is the genus name.
•Second name is the species name
For example:
Human: Homo sapiens
Cat: Felis catus
Dog: Canis lupus familiaris
Gray wolf: Canis lupus
Examples
Genus of maple trees is Acer. It has many species including:
Acer saccharinum
Acer rubrum
Acer saccharum