Chapter 20: Evolutionary Thinking

orthogenesis

the theory that evolution is goal oriented striving to perfect organisms

scala naturae

a term that suggests that evolution proceeds an ongoing process of dynamic adjustment

Charles Darwin

scientist that developed the idea on how evolution occurs bringing up concepts of natural selection

1. observed that not all offspring survive to maturity

2. individuals of every species vary in characteristics and are hereditary allowing some to survive

two predictions that Charles Darwin had on evolution

natural selection

the evolutionary process where alleles increase the likelihood of survival and reproduction of individuals

adaptive traits

genetically based characteristic preserved by natural selection which increases an individuals survival and reproduction rates

1. provided physical rather than spiritual explanations for diversity

2. recognized that evolution occurs in groups rather than individuals

3. described evolution as a multistage process

4. understood that evolution occurs because of a particular environment

four characteristics in Darwin’s Theory of descent with modification

mutationism

suggests that evolution occurs in spurts in chance of appearance of “hopeful monsters” than gradual change

Aristotle

person who believed that inanimate objects and living spaces had fixed characteristics

Carolus Linnaeus

scientists who developed taxonomy (essentially creating a system of naming plants and animals)

taxonomy

the term that is the classification of organisms to an ordered system that indicates natural relationships

biological evolution

process by which some individuals in a population experience changes in their DNA and pass that to their offspring

natural history

branch of biology that examines the form and variety of organisms in their natural envrionments

natural theology

the belief that knowledge of God may be acquired through the study of natural phenomena (eventually biological research took over this concept

biogeography

the study. of geographical distributions of plants and animals

morphology

the form of shape of an organisms or of a part of an organism

vestigial structures

useless anatomical features we observe (no longer have its ancestral function)

fossils

the remains of an organisms embedded and preserved in Earth’s crust

paleobiology

the study of ancient organisms

catastrophism

the theory that Earth went through catastrophic events and apart of the reasoning that each layer of fossils represented organisms that died in those events

Baptiste De Lamarck

scientist that proposed the first thought of evolution based on mechanisms

the metaphysical “perfecting principle” focused on the idea of organisms adapting to their environments

1. the principle of use and disused (body parts grow in proportion to how much they are used)

2. the principle of inheritance and acquired characteristics (changes an animal gains during its lifetime are inherited by offspring)

Lamarck’s two principles for evolutionary changes

1. all species change through time

2. new characteristics are passed throughout generations

3. suggested that organisms change in response to envrionments

4. existence of specific mechanisms that fostered evolutionary change

Lamarck’s 4 contributions to the development of evolution

gradualism

the view that Earth and living systems changed slowly over history (contrasted with catastrophism)

James Hutton

scientist that argued that continuous long slow physical processes produced geological features

Charles Lyell

scientist that argued on uniformitarianism

uniformitarianism

the term that described the geological processes such as catastrophic events are exactly the same processes seen today

artificial selection

the selective breeding or organisms to ensure desirable traits show in generations

population genetics

the term that studies the prevalence and variation in genes among populations of individuals

modern synthesis

the theory of evolution developed in the middle of the 20th century

microevolution

the small genetic changes within populations usually due to shifts in environments

macroevolution

the large evolution patterns in history of life which causes major changes in species (tends to arise from the accumulation of microevolutionary changes)

biological lineages

the evolutionary sequences of ancestral organisms and their descendants

historical biogeography

the study of geographical distributions of plants and animals and relation to evolutionary history

comparative morphology

the analysis of the structure of living and extinct organisms

homologous traits

the characteristics that are similar in two species because they inherited a trait from a common ancestor

the forelimbs grow in front of the tissues

what happens when the Hoxx6 gene is expressed?

the ribs grow

what happens when both the Hoxc6 and the Hoxc8 gene are expressed

ZRS

the zone of polarizing activity regulatory sequences that is an enhancer for the Shh gene that triggers the growth of limbs all the way to animals’ toes

TRPV3 gene

the gene that codes for temperature-sensitive ion channel protein in mammals skin allowing some animals to tolerate cold/ produce shaggy coats