Unit 1 Flashcards
What is biology
Biology is the study of all living things. Al iving things are made up of organic, compounds this means they have carbon.
Organic compounds include: (4)
- Carboyhdrates
- Lipids (fats)
- Proteins
- Nucleic acids ( DNA- deoxyribonucleic acid- & RNA- ribonucleic acid)
When did the first life forms arise on earth and what was it
The first lift-form probably arose on tarth. more than 3.5 billion years ago.
This first organism was likely a single cell called CYANOBACTERIA, too small to be seen w/o a microscope.
For millions of years single celled organisms floating in the seas were likely the only life on Earth.
How old is the universe
The universe is 13.7 billion years old (Big Bang occured btwn 12-14 bilion years ago).
How old is the earth and solar system
The Earth, sun and solar
system are 4.5 billion years old
Characteristics all living things share (6)
- Cells
- Organization
- Energy use
- Homeostasis
- Growth
- Reproduction
Cells
Al living things are composed of cells. Cells are very small, so large multicellular organisms contain many cells.
Organization
All living things are highly organized at both the molecular and cellular levels. specific cell structures carry out particular functions. In organisms, cells and groups of cells are organized by their function
Energy use
All living things use energy in a process called METABOLISM which is the sum of all the chemical process that occur in the organism. Energy is needed to grow and reproduce etc.
Homeostasis
Or balance. All living things maintain stable internal conditions. Ex: a cell closely controls its water content by taking in or releasing water (osmosis)
Growth
All living things grow, as do many non living things. Non living things such as icicles or crystals grow by accumulating more of the material they are made of. Living things grow as a result of CELL DIVISION (mitosis) and cell enlargement
Reproduction
Al species of organisms have the ability ot reproduce. This may be sexually (two parenis) or asexually (one parent).
The fossil record. What does it show?
Fossil evidence shows a long history of life on Earth. The fossil record shows that forms of organisms appeared, lasted for long periods of time, then disappeared, only to be followed by newer forms of life that also disappeared. The history of life is one of constant change and a tremendous diversity of life forms.
What did Nicolaus Steno Propose
He proposed the Law of Superstition in 1669
What is the Law of Superstition
It states that successive layers of rock or soil were deposited on top of one another by wind or water. The lowest layer is the oldest and the top layer is the most recent. This theory gives the history of the Earth.
Why were mass extinctions common
Thought to be because of drastic changes in the environment. Perhaps because of volcanic activity- ash blocks the sun and decreases temperature as well as halts photosynthesis
What is Biogeography
The study of geographical distribution of fossils
i.e. moderns kangaroos only in Australia where the now extinct giant kangaroos lived
What is Evolution
An orderly succession of changes
What is Biological evolution
The changes in a population of organisms over generations
Lamarcks flawed theory. What was his theory about
Jean Baptiste de Lemarck (1744-1829) was the first to propose a theory of evolution.
Is Lamarck’s theory supported
Many who disagree with evolution use his theories which are no longer supported in the science community.
Why do we study Lamarck ⭐️
We study him because he was the first to state that organisms change over time and that physical characteristics could be inherited and were driven by environmental change over time.
What was Lamarck’s hypothesis
He hypothesized that traits acquired over a lifetime are passed to offspring (mostly not true) and that structures formed through repetitive use OR structure could be lost through lack of use (both not true)
i.e. long neck of giraffe formed by repetitive stretching then this trait passed to offspring
i.e. webbed toes of the duck formed by flexing toes, then passed on
Lamarck and Darwin chart
Look at notes
What hypothesis did Darwin and Wallace propose in the mid 1800s
That species were modified by natural selection
Natural selection ⭐️
organisms best suited to their environment survive and reproduce more successfully than other organisms. Thus, over time (perhaps thousands to
millions of years) the proportion of organisms with favourable traits increase in a species
Why was Darwin’s theory known better
Darwin and Wallace proposed their theories at the same time but Darwin’s name is known better after his book ON THE ORIGIN OF SPECIES was published in 1859
What shaped Darwin’s theory (trip)
It was shaped during his 5 year trip aboard the HMS Beagle to South American and the South Pacific
What was one of Darwin’s findings (animal)
One example o f his tindings is the finch. In the Galapagos Islands. Darwin collected i species of finch. They had slightly different bills but otherwise were very similar. This implied that they shareda common anscestor, perhaps a few biras that had been blown from South America. He reasoned that one anscestor could evolve into many species over millions of years
Peppered moths (handout). Which survived
Dark and light moths. The genetic variation is inherited
Most peppered moths in Manchester were light. They were practically invisible on the tree trunks covered with light lichen.
Black moths were very visible and easy prey for birds
Light coloured moths survived bc the birds couldn’t see them. They were more adapted than black moths and lived, reproduced, and had offspring.
What caused black moth populations to rise
During the Industrial Revolution, air pollution from burning coal darkened tree trunks. Light moths stood out more and were picked off by birds. Very few light moths were left to reproduce.
Black moth population increased bc they were now better adapted.
