Lecture week 1 (8-22) - Notes unifying themes and hierarchy

Science

• the process of identifying patterns and asking questions that help us to best understand those patterns.

• the process of disproving hypotheses in an effort to focus in on the true answer to a question.

Hypotheses

specific, testable, rejectable statements

Theory

• a statement that attempts to explain an event and has tremendous amount of evidence supporting the concept and patterns it describes.

• a way of bringing together multiple related, demonstrated hypotheses.

What is scientific advancement based on?

on the assumptions of previous scientific discoveries. What

What does theories consist of:

patterns and process

• patterns: general observations of repetition one sees within a system

• process: the mechanism, or way in which the pattern occurs.

process can be divided into?

proximate vs. ultimate

• proximate: short-term (usually measured in fractions of lifetimes)

• ultimate: longer timeframe (most of a lifetime or more)

what are the two unifying themes in biology?

cell theory and evolutionary theory

• cell theory: all organisms are made of cells and all cells come from pre-existing cells.

• evolutionary theory: all life, as we know it, it the product of evolutionary processes.

What are the two main ideas of cell theory?

• life is continuous

• understanding how an organism works is a function of understanding the structure and function of its cells.

What is a conclusion that can be drawn from Cell Theory?

if you trace a cell’s lineage back far enough, you will conclude that all cells are descended from a common ancestral cell.

Evolution

• the heritable change in a population over time

• a property of populations

What is the primary mechanism of evolution?

Natural Selection

What would happen if heritable traits help individuals produce more offspring?

those traits become more common in the population over time.

What are the two general ideas within evolutionary theory?

• evolution explains variation, how that variation came about, and what can happen if environmental conditions change.

• all species are related to each other through common ancestry. Natural Selection acts on individuals but evolutionary change affects only populations.

The Biological Hierarchy

• a framework of organization regarding all life around us

• provides us with a simple way of guaranteeing we are talking about the same terms as we consider life across varying scales.

• includes: organisms, populations, communities, ecosystems, and the biosphere.

organisms

• individuals - a collection of organ systems, can be single-celled

• acted on by natural selection

• concerned with how the organism behaves, its place in its population, community, etc and how it survives as a result of its behavior and physiology.

populations

• collections of individuals of the same species - typically interbreeding

• gets affected by evolutionary change

• concerned with population growth and evolutionary processes and other changes through time.

communities

• a collection of populations of different species living together in the same area

• boundaries may be set up by natural structures such as mountains, islands, etc or arbitrarily determined by us

• concerned with diversity of species and relationships each species has with other species.

ecosystems

• communities plus their abiotic factors (H2O, temp. geology, etc)

• not the same as biomes

• concerned with, among other things, energy flow ad matter cycling

the biosphere

• all the ecosystems (biomes) put together

• al that gets in is sunlight. all the leaves is heat energy. everything else stays there for good or bad

• concerned with climate change and other global issues

biomes

a collection of very similar ecosystems, largely bounded by global influences like weather and climate.

do units of each level define the next level?

yes, typically the units of one level come together to create the next level

• ex. several organs come together to make up an organism, several organisms come together to make up a population, and so on.

is there a similarity between individuals within each level?

yes, with respects to their structural and functional complexity, even if they have different functions.

Emergent properties

• the collection of the units at one level takes on a trait that is greater than the sum of the parts.

• Smaller parts combine to make increasingly complex systems.