descent with modification: a darwinian view of life

Aristotle

Greek philosopher who profoundly influenced various fields including biology, emphasizing the idea of species being fixed and unchanging. He believed in the great chain of being, a hierarchical structure of living organisms called scala naturae

carl linnaeus

The Linnaean system employs binominal nomenclature to designate species and arrange them into hierarchical categories (e.g, Homo sapiens) was a Swedish botanist and zoologist who developed the system of taxonomy used for classifying and naming organisms, greatly influencing biological classification.

                            Species

Jean-Baptiste Lamarck

A French naturalist known for his early theory of evolution, which proposed that organisms adapt to their environment through use and disuse, passing these traits to their offspring.

Lamarckism

The theory that organisms can pass on traits acquired during their lifetime to their offspring, suggesting that evolution occurs through adaptation to the environment.

Darwin

A British naturalist known for his contributions to the theory of evolution, particularly through natural selection, which explains how species adapt over time.

Wallace

A British naturalist who independently proposed a theory of evolution by natural selection, collaborating with Charles Darwin and prompting the publication of Darwin's work.

Modern theory of evolution

The widely accepted explanation of how species evolve over time through mechanisms like natural selection, genetic drift, and mutation, building on Darwin's original ideas.

•Change in genetic composition (gene pool) of populations over time (generations)

•Life originated from a single common ancestor

Natural Selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring. This mechanism is a key driver of evolution.

Artificial selection

The intentional breeding of organisms with desirable traits to produce offspring that exhibit those traits, often used in agriculture and pet breeding.

Darwin’s four postulates

Observation #1: Members of a population often vary in their inherited traits

Observation #2: All species can produce more offspring than their environment can support, and many of these offspring fail to survive and reproduce

Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals

Inference #2: This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

Adaptations

Physical or behavioral traits that enhance an organism's chances of survival and reproduction in a specific environment.

Observations in nature

The evidence gathered from examining living organisms and their environments, leading to insights about their traits and adaptations.

Homology

The existence of shared ancestry between different species, demonstrated by similarities in structure, genetics, and development.

Shared traits derived from a common ancestor

Vestigial Structures

Anatomical features that have lost their original function through evolution, such as the human appendix or whale pelvis.

Fossil Record

The collection of fossils that provides evidence of the history of life on Earth, illustrating the changes in species over time and the evolutionary processes that have occurred.

Fossils document the pattern of evolution

How Artificial selection and natural selection is similar and different

Both involve changes in traits through selective pressures, but artificial selection is guided by human choice while natural selection occurs through environmental factors.

Homologous Traits

Anatomical features in different species that share a common ancestry, indicating evolutionary relationships, such as the forelimbs of humans, bats, and whales.

Analogous traits

Traits in different species that evolved independently to serve similar functions, demonstrating convergent evolution, such as the wings of bats and insects.

Traits that have a similar function but do not share common ancestry

Convergent evolution

The process by which unrelated species develop similar traits as a result of adapting to similar environments or ecological niches.

Divergent evolution

The process by which related species become more dissimilar over time, often due to different environmental pressures or adaptations.

Linnean Classification

A hierarchical system for organizing biological diversity, established by Carl Linnaeus, that classifies organisms based on shared characteristics into categories such as kingdom, phylum, class, order, family, genus, and species.

Scala Naturae

An early classification system that arranges living organisms in a linear hierarchy from simple to complex, reflecting a belief in a natural order of life.

Evolution

1. the patterns that can be observed in nature

2. The mechanisms that produce the observed pattern of chage

key points of natural selection

1.Natural selection acts on individuals within a population; however, individuals do not evolve, populations do.

2.Only applies to inherited traits that differ between individuals in a population

3.Environments are not static; a favorable trait in one place or time may not be in another.