Themes in Biology Flashcards
Biology
is the scientific study of life.
Properties of life include the following (7) things
Order (organization) Reproduction Growth and development Energy processing Response to the environment Regulation Evolutionary adaptation
Order (organization)
the highly ordered structure that typifies life
Reproduction
the ability of organisms to reproduce their own kind
Growth and development
consistent growth and development controlled by inherited DNA
Energy processing
the use of chemical energy to power an organism’s activities and chemical reactions,
Response to the environment
an ability to respond to environmental stimuli
Regulation
an ability to control an organism’s internal environment within limits that sustain life
Evolutionary adaptation
adaptations evolve over many generations as individuals with traits best suited to their environments have greater reproductive success and pass their traits to offspring
Biological organization unfolds as follows:
Biosphere Ecosystem Community Population Organism Organ system Organ Tissues Cells Organelle Molecule Atoms
Biosphere
all of the environments on Earth that support life
Ecosystem
all the organisms living in a particular area and the physical components with which the organisms interact
Community
the entire array of organisms living in a particular ecosystem
Population
all the individuals of a species living in a specific area
Organism
an individual living thing
Organ system
several organs that cooperate in a specific function
Organ
a structure that is composed of tissues and that provides a specific function for the organism
Tissues
a group of similar cells that perform a specific function
Cells
the fundamental unit of life
Organelle
a structure that performs a specific function in a cell
Molecule
atoms held together by chemical bonds
Atoms
are made up subatomic particles (protons, electrons, neutrons)
All cells
are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings and …….
use DNA as their genetic information.
Cells are the level at which the properties of life emerge.
A cell can
regulate its internal environment take in and use energy respond to its environment develop and maintain its complex organization, and give rise to new cells.
There are two basic types of cells.
Prokaryotic cells
Eukaryotic cells
Prokaryotic cells
were the first to evolve
are simpler
are usually smaller than eukaryotic cells
Eukaryotic cells
contain membrane-enclosed organelles, including a nucleus with DNA
are found in plants, animals, and fungi.
Cells illustrate another theme in biology: the correlation of structure and function.
Structure is related to function at all levels of biological organization.
Living organisms interact with their environments
which include
other organisms and physical factors.
In most ecosystems
plants are the producers that provide the food,
consumers eat plants and other animals, and
decomposers act as recyclers, changing complex matter into simpler nutrients.
The dynamics of ecosystems include two major processes:
The recycling of chemical nutrients from the atmosphere and soil through producers, consumers, and decomposers back to the environment.
There is a one-way flow of energy through an ecosystem, entering as sunlight, converted to chemical energy by producers, passed on to consumers, and exiting as heat.
Genes
are the unit of inheritance that transmits information from parents to offspring,
are grouped into very long DNA molecules called chromosomes, and
control the activities of a cell.
A species’ genes are coded in the sequences of the four building blocks making up DNA’s double helix.
All forms of life use essentially the same code to translate the information stored in DNA into proteins.
The diversity of life arises from differences in DNA sequences.
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Diversity is the hallmark of life.
Biologists have identified about 1.8 million species.
Estimates of the actual number of species ranges from 10 to 100 million.
Taxonomy names species and classifies them into a system of broader groups.
The diversity of life can be arranged into three domains.
Bacteria
Archaea
Eukarya
Bacteria
are the most diverse and widespread prokaryotes
Archaea
are prokaryotes that often live in Earth’s extreme environments.
Eukarya
have eukaryotic cells and include
single-celled protists
multicellular fungi, animals, and plants.
The history of life, as documented by fossils
is a saga of a changing Earth
billions of years old and
inhabited by an evolving cast of life forms.
Evolution accounts for life’s dual nature of
kinship and
diversity.
In 1859, Charles Darwin published the book On the Origin of Species by Means of Natural Selection, which articulated two main points.
- A large amount of evidence supports the idea of evolution, that species living today are descendants of ancestral species in what Darwin called “descent with modification.”
- Natural selection is a mechanism for evolution.
Natural selection
Natural selection is a mechanism for evolution.
Natural selection was inferred by connecting two observations.
Individuals in a population vary in their traits, many of which are passed on from parents to offspring.
A population can produce far more offspring than the environment can support.
Darwin inferred that
those individuals with heritable traits best suited to the environment are more likely to survive and reproduce than less well-suited individuals,
as a result of this unequal reproductive success over many generations, an increasing proportion of individuals will have the advantageous traits, and
the result will be evolutionary adaptation, the accumulation of favorable traits in a population over time.
Human-caused environmental changes
are powerful selective forces that affect the evolution of many species, including
antibiotic-resistant bacteria,
pesticide-resistant pests
The word science is derived from
from a Latin verb meaning “to know.” Science is a way of knowing.
inductive reasoning
Scientists
use inductive reasoning to draw general conclusions from many observations
deductive reasoning
to come up with ways to test a hypothesis, a proposed explanation for a set of observations. The logic flows from general premises to the specific results we should expect if the premises are true.
How is a theory different from a hypothesis?
A scientific theory is
much broader in scope than a hypothesis,
usually general enough to generate many new, specific hypotheses, which can then be tested, and
supported by a large and usually growing body of evidence.
