Life10e Ch01 Lecture-Studying Life part 1

What is Biology

Biology is the scientific study of living

things (organisms).

amphibian species

More than one-third of the world’s

amphibian species are threatened with

extinction.

Could atrazine in the environment affect

species other than amphibians?

Yes, atrazine can impact other species, including fish and invertebrates, through water contamination and ecosystem disruption.

What is a huge threat to amphibians?

Tyrone Hayes studies one of the threats

to amphibians—agricultural pesticides

such as atrazine, which impact breeding

and reproduction

How long was the common origin of life?

Living things are all descended from a

common origin of life that occurred

almost 4 billion years ago.

Sulfolobus

0.5 μm

Escherichia coli

0.6 μm

Coronosphaera mediterranea

4 μm

Phallus indusiatus (stinkhorn mushrooms)

Passiflora quadrangularis (passion flower)

Characteristics of living organisms 1:

1. chemical components such as carbohydrates, fatty acids,

nucleic acids, amino acids

Characteristics of living organisms 2:

2. Most are made of cells enclosed by

plasma membrane

Characteristics of living organisms 3:

3. Convert molecules from their

environment into new biological

molecules and refers to the synthesis of molecules

Example: building glucose from carbon dioxide and water during photosynthesis

Characteristics of living organisms 4:

4. Extract energy from the environment

   and use it to do biological work and refers to the breakdown of molecules to release stored energy Example: glucose is broken down in the presence of oxygen to produce carbon dioxide, water, and usable energy in the form of ATP

Characteristics of living organisms 5:

5. Contain genetic information that uses

a universal code to specify proteins

Characteristics of living organisms 6:

6. Share similarities among a

fundamental set of genes, and

replicate this genetic information when

reproducing

Characteristics of living organisms 7:

7. Exist in populations that evolve through

changes in frequencies of genetic

variants over time

Characteristics of living organisms 8:

8. Self-regulate their internal environment,

maintaining conditions that allow them

to survive

Earth formed how long ago

Earth formed 4.6 to 4.5 billion years ago

but it was 600 million years or more before

life evolved

The history of Earth can be pictured as a

30-day month….?

1. Origin of life 2. Oldest fossils 3. Origin of photosynthesis 4. Origin of eukaryotic cells 5. Multicellular organisms 6. Abundant fossils of aquatic life 7. First plant/land animals 8. Coal-forming forests, insects abundant, first mammals, dinosaurs dominant 9. first birds, first flowering plants, rise of mammals.

Pics of Cell membrane, membrane of nucleolus, and mitochondria

2 billion years ago, life consisted of single

cells

prokaryotes

The two main groups of prokaryotes

emerged early

bacteria and archaea

An organism consisting of one or more cells in which the genetic material is DNA, organized into chromosomes, contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaea

eukaryotes

Eukaryotic cells

internal membranes

that enclose specialized organelles

within their cells, including the nucleus,

which contains the genetic material

photosynthesis

transforms sunlight energy

into biological energy.

About 2.5 billion years ago

photosynthesis changed the nature of

life on Earth

What does photosynthesis do for earth?

provides food

Early photosynthetic cells were probably

similar to

cyanobacteria (which are a type of prokaryotes)

The atmosphere of early Earth had no O2,

but it began to increase as

photosynthetic prokaryotes increased.

O2

in the atmosphere allowed life to move to land

O3 layer (ozone layer)

which absorbs

damaging UV radiation.

By 500 million years ago

there was enough ozone to leave the protection of water

Genome

: the sum total of all the DNA

in a cell (is the complete set of genetic material in a living organism.)

DNA consists of repeating subunits

called

nucleotides (there are 4 billion in a human body) and is the basic building block of DNA and RNA.

Gene

a specific segment of DNA that

contains information for making a

protein.

Evolution

is the major unifying principle of biology, the strongest change and continue to live

Charles Darwin

Compiled factual evidence for evolution.

differential survival and

reproduction

among individuals in a

population (natural selection) could

account for much of the evolution of life.

Natural selection leads to

adaptations: structural, physiological, or

behavioral traits that enhance an

organism’s chances of survival and

reproduction.

Adaptations to the Environments

Each species has a distinct scientific

name, a binomial:

Genus name – species name

Example: Homo sapien

genus

is a group of species that share

a recent common ancestor.

evolutionary

relationships

describe the connections between different species through shared ancestors, revealing how all life forms are interconnected through common descent.

molecular techniques

Molecular techniques are laboratory methods used to manipulate, analyze, and study biological molecules such as DNA, RNA, proteins, and lipids at the molecular level. (such as the ability to sequence genomes.)

phylogenetic tree

biological hierarchy

Movement (cellular work)

of molecules or the

whole organism

Synthesis (cellular work)

Synthesis—building new complex

molecules from smaller chemical

unit

information

processing (cellular work)

Electrical work of information

processing in nervous systems

homeostasis

Maintenance of the narrow range of

conditions that support survival/ regulating their internal environment of extracellular fluid (example: shivering to generate heat)

hypothesis–prediction

1. Making observations

2. Asking questions

3. Forming hypotheses, or tentative

answers

4. Making predictions based on the

hypotheses

5. Testing the predictions

Controlled experiments

the whole test where you control the other factors

experimental

receives the change or treatment you're testing.

independent variable

the variable

being manipulated

Dependent variable

the response that

is measured.

Statistical methods

Are used to see if difference are significant

Statistical tests

start with a null

hypothesis: that no differences

exist + analyzes the data to see if there is a significant difference or relationship.

Religious or spiritual

explanations of

a natural phenomenon are not

testable and therefore are not

science

Knowledge of plant biology

has

increased food production, which

has allowed the planet to support a

larger human population.

New strains of crop plants

are

developed to resist pests or tolerate

drought. (peanuts, sweet potatoes, fig)

medical practice.

Biological research explains how

organisms work and why they develop

problems and diseases

genetic variation

That raises ethical and policy questions because changing DNA can affect people, future generations, and society.

Human activities

Make unprecedented rates of change in Earth

systems.

Increasing atmospheric CO2

is

responsible for climate warming which is

contributing to species extinctions and

spread of diseases.

Applicant of results

Are an important part of science example: Molecular mechanisms of atrazine’s

effects are similar in amphibians, fish, reptiles, and human cell cultures