38 terms

Animal Biology - Unit 21


Terms in this set (...)

A process that builds and organizes knowledge about the universe.

-Collect and analyze information
-Science changes over time
Rigorous scrutiny
New Ideas and discoveries are scrutinized, questioned, and evaluated until all evidence supports them.
Fixed species
Idea that species were fixed in form and were not able to change over time.
Scala Naturae
All living organisms arranged in a linear order form simple to complex
- "great chain of being"
- Human at the top
Observation 1
Organisms exhibit variation that can be passed from one generation to the next.
Observation 2
Organisms compete for available resources.
Observation 3
Individuals, within a population, differ in terms of reproductive success
Differential reproductive success
Certain individuals have favorable traits that enable them to better compete for limited resources and reproduce
The ability of an individual to pass his/her genes on to the next generation

-More offspring = higher fitness
Observation 4
Organisms appear to be well suited to their particular environments.

Short grass = short neck
Tall grass = long neck
Theory of Evolution
The gradual change in the inherited traits of a biological population over time.
Natural Selection
process by which heritable traits become either more or less common in a population due to their effect on survival and reproductive success.

-Key mechanism of evolution
-Survival of the fittest"
The heritable modification in structure, function, or behavior of a species that makes it better suited to its environment

-Driven by natural selection and mutation
Is there a goal to natural section
No! There is not "perfect form" for a species
-Traits that may become more or less beneficial
A process that can retain complexity (survive) and replicate (reproduce)

-Darwinian evolution only is used to explain every aspect of living systems not the origination of life.
Allow for living systems to become better or worse at surviving and/or reproducing in a given environment

-Life diversified to adapt to almost every available niche on Earth
The interrelationship of a species with all the living and non-living factors affecting it.
Evidence for evolution - 5
Fossil evidence
Artificial selection
Comparative and Develiomental anatomy
Sedimentary rock
Rock formed by gradual accumulation of sediment (sand, rock, dirt), as in riverbeds and the ocean floor

-For distinct layers basked on conditions of the environment
Principle of superposition
Lower layers of rock are older than those above

- The process of sedimentation is asymmetrical - new sediments cannot be deposited below existing layers of sediment
Any trace of an organism that existed in the past (>10,000 yo)
Fossil record
The remains or imprints of organisms from earlier geological periods preserved in sedimentary rock

-Age of organism is determined by which layer of sediment they are in.
Transitional fossils
Any fossilized remains of a life form that exhibits traits common to both an ancestral group and its descendent group

- Exhibits traits that are intermediate between those of older and younger species.
The study of the distribution of species and ecosystems across the planet
Plate tectonics
Earth's surface consists of several plates that move in response to forces deep in earth's core

-Plates are constantly moving and smashing into each other at a relatively (to humans) slow rate
Continental drift
Movement of Earth's continents relative to each other due to plate tectonics!
-Continents appear to "drift" back and forth across the ocean
Artificial Selection/ selective breeding
The process by which humans breed organisms for a desired set of traits.

-Similar to natural selection except humans select desirable traits as opposed to the environment
Comparative anatomy
The study of similarities and differences in the anatomy of different species
Homologous structures
anatomically similar structures in different organisms that may serve different functions.

-Derived through inheritance from a common evolutionary ancestor
Analogous structures
Biologic structures that share the same function but not the same anatomical structure

-NOT due to shared common ancestry by convergent evolution
Convergent evolution
process of natural selection in which features of organisms not closely related come to resemble each other as a consequence of similar selective forces
Vestigial Structure
Remnant of a structure that was functional in an ancestor but is no longer functional in the organism in question

-Trait is no longer useful for enhancing reproductive success
Developmental homology
Similarity in embryonic form, or in the fate of embryonic tissues

-Similarities due to shared common ancestor
Genetic homology
Similarity in the DNA sequences of genes from different species.

-All living organisms use DNA to store information.
Comparative genomics
Utilizes nucleotide sequencing to compare relatedness of organisms

-Compare DNA sequences , genes, etc.
Modern evolutionary synthesis
All living things share a common ancestor and genetic mutations in organisms create heritable variation upon which natural selection acts.

-Also states that all living organisms share a common ancestor
Scientific theory
Is a concept supported by a broad range of observations, experiments, and data often from a variety of disciplines.

-Equivalent to physical laws
What does the evolution propose?
Life changed as a result of random events; clearly traits are too complex to have originated "by chance"...