Bio Test Unit 8 Flashcards

During his voyage on the HMS Beagle, Charles Darwin made key observations like the variation of species across different geographic locations, particularly on the Galapagos Islands, where he noticed distinct variations in finch beaks depending on their diet and environment; this led him to conclude that species can change over time through a process called "natural selection," where organisms with advantageous traits for their environment are more likely to survive and reproduce, leading to the evolution of new species over generations.

Developed the concept of uniformitarianism.

He's the author of the Principles of Geology.

French naturalist and biologist is most recognized for proposing a theory of evolution, now called Lamarckism, which suggested that organisms could acquire or lose traits based on how much they used them during their lifetime and that these acquired traits could be passed on to their offspring; essentially, "use it or lose it" concept applied to evolution.

Thomas Malthus, an English economist, is most known for his theory arguing that population growth will inevitably outpace the food supply if left unchecked, leading to widespread famine and other societal issues

Independently came up with the same theory as Darwin.

intrasexual selection (competition between individuals of the same sex for mates) and intersexual selection (mate choice, where one sex actively selects mates based on specific traits), and these mechanisms can lead to sexual dimorphism by causing distinct physical and behavioral differences between males and females within a species due to different selective pressures on each sex when competing for mates.

The four main categories of evidence supporting evolution are: fossil record, comparative anatomy (including homologous structures), molecular biology (DNA analysis), and biogeography

Convergent evolution occurs when unrelated species develop similar traits due to similar environmental pressures, while divergent evolution happens when a single species or closely related group evolves into distinct species with different characteristics, usually because of different selection pressures in their environments

"homologous" refers to structures that share a common ancestor, even if they have different functions, while "analogous" refers to structures that have similar functions but evolved independently in different species, meaning they do not share a common ancestor

Relative dating determines the age of an object or fossil in comparison to other objects, placing them in a chronological sequence without providing a specific numerical age, while absolute dating provides a precise age for an object using methods like radiometric dating, giving a specific number of years old it is.

because there is no single perfect way to categorize organisms across the vast diversity of life on Earth, and different criteria may be necessary depending on the organism, its environment, and the available data; this leads to various "species concepts," each with its own strengths and limitations, such as the biological species concept (based on reproductive isolation), the morphological species concept (based on physical appearance), and the ecological species concept (based on niche occupation).

The three main types of selection pressure are: stabilizing selection (favoring the average phenotype), directional selection (favoring one extreme phenotype), and disruptive selection (favoring both extreme phenotypes).

Allopatric speciation occurs when a population is geographically separated by a physical barrier, like a mountain range or river, leading to the evolution of new species in separate locations, while sympatric speciation happens within the same geographic area, with no physical barrier, where a new species arises from a single ancestral population due to factors like behavioral changes or polyploidy.

Microevolution refers to small changes over short periods of time within a population. Macroevolution refers to larger changes over a much longer time scale. Macroevolution can result in speciation or the emergence of new species.

the theory that evolutionary changes happen gradually over time, rather than suddenly or in large steps.

Punctuated equilibrium describes a process of evolution that suggests very short, rapid periods of change followed by long periods of stability

the formation of Earth itself, the development of its core and crust, the formation of the first oceans, the emergence of early life forms, the oxygenation of the atmosphere, the appearance of multicellular organisms, the formation of continents, major mass extinction events, the movement of tectonic plates, and the evolution of different life forms throughout geological eras, including dinosaurs and mammals.

According to current scientific understanding, the first organisms on Earth were likely single-celled prokaryotes, similar to bacteria, which thrived in the early oceans and could feed on existing carbon compounds; following this, more complex organisms like photosynthetic bacteria (cyanobacteria) emerged, then eventually led to the evolution of eukaryotic cells, which paved the way for multicellular organisms like algae, simple invertebrates, and eventually animals and plants on land.

A "primate" is a broader category of mammals that includes monkeys, apes, and humans, while a "hominid" specifically refers to the family of great apes, which includes humans, chimpanzees, gorillas, and orangutans, essentially making all hominids considered primates, but not all primates are hominids; meaning humans are classified as both a primate and a hominid.