Evolution 5-Evidence of Evolution Flashcards
What are the lines of evidence that support Darwin’s Theory?
- Fossil records
- Artificial Selection
- Anatomical Evidence
- Genetic Evidence
How are fossil records a line of evidence that support Darwin’s Theory?
- Layers of sedimentary rock contain fossils.
1. New layers cover older ones, creating a record over time.
2. Fossils within layers show that a succession of organisms have populated Earth throughout a long period of time
Fossils Definition
Any preserved remains or traces of an organism or its activity; many fossils are of such hardened body parts as bone
Fossilization Definition
The process by which traces of past organisms become part of sedimentary rock layers or, more rarely, hardened tar pits, volcanic ash, peat bogs, or amber.
Paleontology Definition
The scientific study of fossil remains; Paleao = old/primitive; onto = of being; logy = the study of
Fossil Record Definition
A record showing us that today’s organisms descended from ancestral species
What are some of the evolutionary changes in horses?
- An increase in size
- A loss of toes
- An increase in size of molars
Fossils and Dates-What is one technique used to date rocks?
One technique used to date rocks is radiometric dating.
Radiometric Dating Definition
A technique used to date rocks, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.
How have birds evolved?
-From Archaeopteryx, which
lived about 150 million years ago, and links reptiles & birds.
How have land animals evolved?
- In 2006, there was a Fossil Discovery of an Early Tetrapod.
-This tetrapod was called the “Tiktaalik”
-It was considered the “missing link” from sea to land animals: from swimming (0 legs) to walking (4 legs).
What is involved in Artificial Selection?
Humans “improving” domesticated plant and animal species for thousands of years of selection
Artificial Selection Meaning and Examples
- Selecting offspring with desirable traits as breeding stock for succeeding generations.
-For example:
1. Farm animals
2. Cats, and dogs
3. Flowering plants
4. Crops
Selective Breeding Definition
The process of breeding plants and animals for desirable traits.
What are Homologous Features? What are examples?
- Structures that share a common origin/ancestry but may serve different functions in modern species
-E.g. dolphin flippers and human hands
What are Analogous Features? What are examples?
-Structures similar in function but not in origin or anatomical structure
-E.g. wings of birds and bees, or the eyes of lobsters and fish
What is the meaning of Comparative Embryology?
When there is similar embryological development in closely related species.
What similarities do all vertebrate embryos have with each other?
All vertebrate embryos have similar structures at different stages of development.
What is an example of a structure that all vertebrate embryos have?
A gill pouch; they can be found in the embryos of fish, frogs, snakes, birds, humans, etc.
What is an example of Convergent Evolution?
- Fish are aquatic vertebrates. - Dolphins are aquatic mammals.
- They have similar adaptations to life in the sea, but are not closely related.
Convergent/Parallel Evolution Definition
Describes the acquisition of the same biological trait in unrelated lineages
Convergent/Parallel Evolution Example/What leads to the natural selection of similar traits?
Similar environments & niches lead to natural selection of similar traits.
What has there been on different continents?
On different continents, there has been evolution of similar looking species that fill similar niches.
What is Convergent/Parallel Evolution responsible for?
It is responsible for analogous structures.
Vestigial Structures Definition
- Structures that serve no useful function in a living organism but are remains of ancestral structures.
- Rudimentary and nonfunctioning structures that are homologous to fully functioning structures in closely related species
Examples of Vestigial Structures
-Dogs have a vestigial toe; although the bones remain, this digit serves no present purpose.
-Pigs’ feet have two well-developed digits; the others are vestigial.
-The horse has only one enlarged digit; the others are vestigial or have been lost entirely.
What are vestigial organs traces of?
Vestigial organs are traces of homologous organs in other species.
What function do vestigial organs serve?
Vestigial organs are organs that serve no useful function.
What are examples of vestigial organs?
-e.g. Appendix, Wisdom Teeth, and Tailbone in Humans
- Pelvic Bones in Whales
- Hind Leg Bones in Snakes
- Dew Claw in Dogs
What are other examples of vestigial organs/structures?
-Some beetles have fully developed membranous wings underneath fused covers, so that it is impossible for them to open these wings.
-Humans have muscles for moving ears, much as dogs and other mammals do.
-Very large numbers of vestigial genes in the DNA of living organisms; these genes do not function, yet they bear a striking resemblance to functioning genes.
-Appendix in humans
-Human “goosebumps”
-Rudimentary wings in many flightless insects such as earwigs.
-Rudimentary eyes (or empty eye sockets) in blind cave-dwelling fish and amphibians.
Why would Genetic Evidence be a line of evidence that supports Darwin’s ideas?
- The sequence in DNA and proteins is a molecular record of evolutionary relationships.
- You can compare common genes, such as cytochrome C (respiration), and hemoglobin (gas exchange).
How can Phylogenetic Trees be considered, “Family” Trees?
Closely related species (branches) share same line of descent until their divergence from a common ancestor
Phylogenetic Tree or Evolutionary Tree Definition
A branching diagram or “tree” showing the inferred evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical and/or genetic characteristics
Cladogram Definition
A diagram which shows ancestral relations between organisms, to represent the evolutionary tree of life
How does Artificial Selection compare with Natural Selection?
Natural selection
1. It is the process where organisms adapt to their environment for their survival.
2. It is a natural selection process.
3. It helps in producing organisms with biological diversity.
4. It occurs in natural populations.
5. It is a slow process.
6. It helps in inheritance of only favourable characters to the successive generations.
7. Example: Selection of long-necked giraffes.
Artificial selection
1. It is process in which a plant breeder selects plants with characteristics to produce offspring with desirable traits. 2. It is a man-made selection process.
3. It helps in producing organisms with selected desirable traits.
4. It occurs in the reared or domestic population.
5. It is a rapid process.
6. It helps in the inheritance of a variety of desired selected traits to the successive generations.
7. Example: Breeding of different varieties of dogs or cattle to produce the desired varieties.
What are the disadvantages of Artificial Selection?
-Reduction of genetic diversity.
-Knock-on effects on other species.
-Genetic mutations can still occur.
What are the advantages of Artificial Selection?
- Crops with a higher yield
- Crops with a shorter harvest time
- Crops with higher resistance to pests and diseases
- Reduce costs because farmers can identify crops or animals from their resources to be used
- Create new plant and animal varieties with selected desirable traits.
What is the end result of Artificial Selection?
Offspring with selected desirable traits.
