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
All 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.
Why is light moth population now increasing
Pollution control measures increased and trees are becoming lighter so the population of light moths is increasing
How many species of finches are there
13
Explain the finches and what Darwin thought
•Each species is adapted to the particular local environment. Darwin thought the various species arose from a common anscestral type
• According to this theory, a pregnant female, or pair of finches arrived on one of the Gala pagos Islands.
• The anscestral type is thought to have beead a sone spaped beak that was adapted for crushing seeds
• Finches spread out to different islands. Each group remaned isolated in is own niche. Finches with characteristics that helped them to adapt survived and reproduced.
• Gradual changes resulted in the development of new species from the anscestral type.
Explain the 6 species of ground finches
There are six species of ground living finches. Three of them eat seeds but diff kinds of seeds. The fourth species has a long pointed beak and eats prickly pears. Other two species eat cacti
Explain the 6 species of tree finch
6 species of tree finch. 1 eats buds &e fruit with a parrot beak. 4 insect. eating species. Another species eats insects & uses a twig to dislodge insects from tree bark.
Where are the 13 species thought to have come from
Evolved from one common ancestor
Do the finches interbreed
No. When placed into cuntact wi eachother they do not interbreed
Adaptive radiation
In adaptive radiation, one form of life spreads to a variety of habitats, separates into isolated groups and evolves into dift species over time
Darwin’s theories (2) ⭐️
- Descent with Modification
- Modification by Natural Selection
Theory 1. Descent with modification ⭐️ (3pts)
•States that newer forms appearing in the fossil records are actually the modified descendants of older species.
• Also stated that ALL living things descended from one, or a few common anscestors millions to billions of years agos
•This theory also accounted for the fact that similar organisms arise in the same geographical location (fig 15-6 pg. 281)
Theory 2. Modification by Natural Selection ⭐️ (3 pts)
3 points.
- Overproduction
- Variation
- Adaptation
Overproduction
more organisms are born than can ultimately survive. There is competition within the species for food, habitat, survival from being eaten
Variation
when organisms are born they are not all the same. There is variation (heritable differences that exist among individuals) that exists in every population (all the individuals of a species that live in an area and are capable of interbreeding) Natural-selection acts on existing variation and it acts on phenotypes (physical traits (ubservable)
Adaptation
the “strong” or “best suited” that are selected by the environment due t o changes in climate, topography, food supply, predators ete) survive and pass these characteristics on to their ottspring and these traits become more common in the population over time
- “survival of the fittest” does NOT mean the “strongest” survive, “fit” is a measure of the ability to survive and produce more offspring
What does survival of the fittest mean
“survival of the fittest” does NOT mean the “strongest” survive, “fit” is a measure of the ability to survive and produce more offspring
4 points of Lamarcks theories
- Environment changes thus creating a “need” to change (making it sound voluntary)
- Development of new ACQUIRED features “in order to survive” or “so one can survive”. Acquired traits arise during the lifetime of an organism and don’t change its genotype. Ex: walking with a limo bc of previous broken leg
- Newly acquired traits (through use and/or non use) somehow get passed down to offspring
- New species eventually
4 points of Darwin’s theory (chart)
- Environment “screens out” (or SELECTS) features contributing to survival, and tends to eliminate others
- Variations of inheritable features which already normally exist organisms are all a little bit afferent
- Those with traits which help survival tend to survive and have more offspring, who inherit those traits.
- New species, eventually
Why are albino animals rare/don’t survive
Ex. albino birds not surviving in wild because they stand out and. are easier for predators to see, also more prone to cancers (skin, eye, etc.)
How were fossils formed
Fossils formed and were covered with sand or mud. Layers formed and turned into sedimentary rock. Some event such as the erosion of the Grand canyon or the building of a highway exposed the fossils again.
How can the age of fossils be determined
The use of potassium and uranium, mass and half life, or Carbon 14
Potassium/half life and dating fossils
Potassium has a half-life of 1.3 billion years. This means that it takes 1.3 billion years for half its mass to disintegrate. Potassium can be used to determine the age of the oldest fossils is 3.5 billion years old
Carbon 14 and fossils
Carbon 1 4 can b e used to age the actual fossil. Carbon 14 decays into Nitrogen 14 which has a half life of 5730 years. It is the ratio of carbon to nitrogen that indicates the age of the fossil.
For ex. if the measured abundance of C14 and NI4 in bone are equal, one half life has passed and the bone is 5730 years old (Amt equal to the half life of C14). If there is 3 times less C14 than N14 in the bone, 2 half-lives have passed and the sample is 11,460 years old.
Plate Tectonics
⭐️ who proposed the Continental drift
proposed by Wegener, a German scientist in 1912.
⭐️ what did Wegener suggest (continental drift)
He suggested that the present continents had once been joined in a supercontinent he called Pangaea. He thought that these big land masses were floating apart over the Earth’s hot liquid interior.
Was his hypothesis accepted at the time? Is it now and what is the theory called
His hypothesis was not well accepted at the time but is now part of a broader theory called PLATE TECTONICS.
Mechanism of continental drift
molten rock from the Earth’s interior forces its way through the ocean floor, cools and begins to move away from this ridge. Where it meets the land it is forced beneath the continent. This is what forms mountains, volcanoes and earthquakes.
Ring of Fire
areas where the plates meet and where 90 % of earthquakes occur.
Plate Tectonics Explains Species Distribution
• Forms new islands such as the Galapogos which create new environments for new species.
• As Pangaea broke up it isolated species into groups. This is how small pockets of strange species like marsupials and placental mammals are thought to have been separated.
Marsupials are found only in Australia and South America which are thought to have been joined together as Pangaea.
Mammal and marsupial chart
What causes Variation?
Variation in a species can be caused by mutation, migration or nonrandom mating.
Biological Species Concept
A species is a population of organisms that can successfully interbreed but cannot breed with other groups
Isolating Mechanisms - How do species give rise to other different species?
Speciation begins with ISOLATION. In isolation two parts of a formerly interbreeding population stop interbreeding.
2 kinds of isolation
Geographic isolation
Reproductive isolation
Geographic Isolation
physical separation of members of a population. This could be caused by continental drift or a deep canyon for example. Once the subpopulations become isolated gene flow between them stops. Natural selection causes the two groups to become less alike. Eventually they are incompatible for mating.
Reproductive isolation
results from barriers to successful breeding in groups in the same area. If the two extremes of a trait are selected for, the organisms may become so different that they are unable to mate. An example of this could be a toy poodle and a Newfoundland dog. The extreme sizes may cause the dog populations to become separate species.
Temporal isolation
exists when timing prevents reproduction between populations. To reduce competition, courtship signs or reproductive periods may change.
Ex: Monterey and Bishop pine have different pollination periods N p 326
Behavioral isolation
- isolation caused by different courtship or mating behaviors. Ex: firefly light flashing patterns are specific to each species. N p 325
Extinction
The elimination of a species from Earth is called extinction.
What causes extinction
Extinction often occurs when a species as a whole is unable to adapt to a change in its environment
Rates of Speciation
- Gradualism
- Punctuated Equilibrium
Gradualism
a slow smooth process that occurs over many generations and millions of years. N p 283 & 285
Punctuated Equilibrium
occurs much more quickly
(100-1000s of years.) N page 331
Homeobox or Hox Genes (2 pts)
• Any of the developmental control genes that define the head-to tail pattern of development in animal embryos. (Homeotic genes control early development in animals)
• The first hox gene was discovered in Drosophila (fruit flies.) Mutation in this gene leads to the formation of a normal structure or organ in place of another at an abnormal site. i.e. mutation in the antennapedia hox gene of Drosophila leads to the formation of leg in place of antenna from its head.
What does epigenetics literally mean
Epigenetics literally means “above” or “on top of” genetics.
Explain epigenetics
It refers to external modifications to DNA that turn genes “on” or “off.” These modifications do not change the DNA sequence, but instead, they affect how cells “read” genes.
Epigenetics definition
Epigenetics refers to the idea that environmental factors can change how a DNA sequence is expressed.
How are epigenetics similar to Lamarcks ideas
This is somewhat similar to Lamarck’s ideas that characteristics acquired over a lifetime DO or MAY affect your DNA.
