Chapter 13 Part 1 - Evolution Flashcards
What did Aristotle believe about evolution?
He thought that species were fixed and unchanging.
What did Carolus Linnaeus contribute to our understanding of species?
The binomial naming system/ taxonomy.
Each species has a species name and a genus name and are grouped into increasingly general categories.
What principal categories or “taxons” does modern taxonomy use?
(most general to most specific) Domain, Kingdom, Phylum, Class, Order, Family, Genus, and species.
What is Georges Cuvier considered the father of? What is he known for?
Palaeontology – the study of fossils.
He was first to document that the history of life on earth was recorded in layers of rock.
What is catastrophism?
The theory that earth has mostly been shaped by short, sudden, violent events. (George Cuvier believed in this)
What is gradualism?
A principle proposed by James Hutton stating variation in landforms can be explained by mechanisms currently operating in the world (i.e. erosion) and profound changes were the cumulative product of slow but continuous processes.
What is uniformitarianism?
It’s like gradualism + geological processes are uniform so their rates and effects must balance out through time. (i.e. growth and erosion of mountains).
What are the two conclusions of Charles Lyell’s theory (uniformitarianism)?
- Geological change results from slow continuous processes, not sudden events.
- The earth must be very very old!
What two well-known phenomena in nature were still unexplained as people began to view their world as more dynamic?
- Plants and animals show a graded series of “perfection” (i.e., there is continuous variation).
- The amazing diversity of organisms.
What was Jean Baptiste Lamarck’s theory to explain how life evolves?
Slowly and gradually old species can transform into new ones as the modifications an organisms acquired during its lifetime could be passed along to its offspring.
How was Jean Baptiste Lamarck’s theory of evolution incorrect?
He theorized that evolution worked on the level of the individual organism and was based on “inheritance of acquired characteristics” through use and disuse of body parts which is not quite accurate.
Where did Darwin travel and which place had the biggest impact on his research?
He traveled around the world on the HMS Beagle. The voyage intended to chart the South American coast.
The Galapagos Islands where many species were unique to the islands.
How did Darwin perceive the relationship between adaptation and the origin of new species?
Darwin saw them as closely related processes. A new species would arise from an ancestral form by gradual accumulation of adaptations to a different environment.
What big concept did Darwin present in “On the Origin of Species by Means of Natural Selection”?
Descent with modification = natural selection.
Species accumulated diverse adaptations (modifications) suited to their particular environment over millions of years.
What influenced Darwin as he was coming up with his theory of evolution via natural selection?
Darwin was strongly influenced by Charles Lyell’s book “Principles of Geology” and seeing an earthquake in Chile shows that natural forces are still shaping Earth.
What is the first of two observations and inferences that Darwin’s theory of natural selection was based on?
Members of a population often vary in their inherited traits. So those with traits that increase their probability of surviving tend to have more offspring
What is the second of two observations and inferences that Darwin’s theory of natural selection was based on?
All species are capable of producing more offspring than the environment can support. So unequal production of offspring will lead to accumulation of favourable traits over generations.
What is the essence of natural selection?
The essence of natural selection is unequal reproduction. Animals that out compete others are more able to pass on their genes.
Do individuals of a population evolve?
Individuals DO NOT evolve. It is the population, the group of organisms, that evolve over time as adaptive traits become more common.
Does natural selection affect an organism’s acquired/learned characteristics?
Natural selection can only amplify or diminish heritable traits. Unless coded for in the genes of an organism’s gametes, acquired/learned characteristics cannot be passed down to their offspring.
Is evolution goal directed?
NO! Evolution is just the result of responses to environmental factors that vary from place to place and over time.
Is natural selection more like an editing process or creative mechanism? Why?
It’s like an editing process because it does not create new, useful alleles it just selects for already existing, useful alleles.
Is natural selection dependant on time and place?
Yes, it favours location and time specific conditions. Useful adaptations may become useless if conditions change.
What are some sources of evidence for natural selection?
We can observe natural selection in our use of pesticides, insecticides, herbicides, and antibiotics. Fossils also provide strong evidence. So does biogeography, comparative anatomy, and molecular biology.
What is the fossil record and its relation to evolution?
It is the sequence in which fossils appear within layers of sedimentary rock, it provides some of the strongest evidence for evolution.
Which body parts/types of organisms are most likely to fossilize?
Hard parts of animals rich in minerals (bones, teeth, shells). Soft bodied organisms don’t fossilize as well.
How can fossils be made of stone and not the actual remnants of organisms?
An organism is captured in sediment, decays but leaves an empty mould. It’s filled by minerals dissolved in water which harden into a replica of the organism.
What are trace fossils?
Footprints, burrows and other remnants of an ancient organism’s behaviour. They provide “traces” of the organism’s existence.
What is a fossil?
A preserved remnant or impression of an organism that lived in the past.
Does the fossil record show a complete history of living things?
No, it’s incomplete. Many organisms do not fossilize well, conditions in many areas are not conducive to forming fossils, many fossils have been destroyed by natural events and not all fossils are found.
What is the oldest fossil? How old is it?
Prokaryotes that have been
dated back to 3.5 billion years ago
How long after the first prokaryotes did single-celled eukaryotes appear? Then how long until multicellular eukaryotes appeared?
More than a billion years.
Then approx. another billion years before multicellular eukaryotes appeared.
What do fossils show us about the evolution of whales?
They are related to land mammals in the family of pigs, hippos, cows, camels and deer. Their mammal ancestor slowly moved into the sea.
What is biogeography?
The study of the geographic distribution of species.
How did Darwin observe biogeography?
He saw that animals on the Galapagos had migrated from South America and became new species as they adapted to the environment.
What is comparative anatomy?
The study of similarities and differences in the anatomy of different species. Lots of anatomy appears to come from a common ancestor.
What are homologous structures?
Features that often have different functions, but that are structurally similar because of a common ancestor. i.e. mammal forelimbs have similar bones, muscles, and nerves.
What can comparison of early life stages in different animal species show?
It can reveal more homologies not visible in adult organisms. i.e. ALL vertebrate embryos have a tail and pharyngeal (throat) pouches which develop into very different structures.
What are vestigial structures?
Structures that serve only a marginal or even no important function to the organism. They are remnants from the organism’s ancestors.
How does microbiology support the theory of evolution?
Comparing DNA sequences shows how closely related organisms are. Sequences that match closely must have been inherited from a relatively recent common ancestor.
What was Darwin’s boldest hypothesis? Is there evidence to support this?
ALL LIFE FORMS ARE RELATED. Today, molecular biology provides strong evidence for this claim.
How do we visually display patterns of descent?
Through the use of evolutionary trees! Darwin was the first to view the history of life as a tree.
How do we determine where to put branches on the evolutionary tree?
Through the use of homologous structures, both anatomical and molecular. Characteristics that evolved more recently are shared within smaller groups of organisms
Does the theory of evolution tell us how life first arose?
No, not at all.
Did humans evolve from chimps or monkeys?
NO.
At some at point we shared a common ancestor, and chimps are our closest living relative from that extinct ancestor.
