BIOL 121a Final Exam Chapters 1-5

Common ancestry means that different species share a common ancestor from which they have evolved

Evolution is the process by which different kinds of living organisms develop and diversify from earlier forms during the history of the Earth. It involves changes in the genetic makeup of populations over successive generations

Variation: Individuals within a population have different traits.

Inheritance: Traits are passed down from parents to offspring.

Selection: Some traits provide a survival or reproductive advantage.

Time: Over many generations, advantageous traits become more common.

Adaptation: The population becomes better suited to its environment.

The fossil record is the collection of all known fossils and their placement in rock formations and sedimentary layers. It provides evidence of the history of life on Earth, showing how different organisms have evolved over time.

The Cambrian Explosion was a period around 541 million years ago when there was a rapid increase in the diversity of life forms on Earth. Many major animal groups first appeared during this time.

Homology refers to the similarity in structures or genes between different species due to shared ancestry.

Ontogeny refers to the development and growth of an organism from the earliest stages of life, such as fertilization, through to maturity. It encompasses all the changes an organism undergoes during its lifetime, including embryonic development, growth, and differentiation of cells and tissues.

Speciation is the process by which populations evolve to become distinct species.

A species is a group of organisms that can interbreed and produce fertile offspring.

Reproductive barriers are mechanisms that prevent different species from interbreeding and producing fertile offspring. they can be broken into 2 types

- Prezygotic

- Postzygotic

Adaptive radiation is when a single species rapidly evolves into multiple new species, each adapted to different environments.

Gradualism is the idea that evolutionary changes happen slowly and steadily over time.

Punctuated equilibrium is the theory that evolution happens in rapid bursts, followed by long periods of stability.

Natural Selection: The process where organisms with advantageous traits are more likely to survive and reproduce.

Artificial Selection: Humans selectively breed organisms for desired traits.

Sexual Selection: Traits that increase an organism's chances of mating are favored.

Directional Selection: Favors one extreme phenotype over others, causing a shift in the population.

Stabilizing Selection: Favors intermediate phenotypes and reduces variation.

Disruptive Selection: Favors extreme phenotypes at both ends of the spectrum, leading to increased variation.

Balancing Selection

Maintains genetic diversity in a population by favoring multiple alleles.

Neo-Darwinism is the modern synthesis of Darwin's theory of evolution combined with Mendel's principles of genetics.

Microevolution refers to small genetic changes within a population over a short period.

Macroevolution refers to large-scale evolutionary changes that lead to new species over long periods.

Systematics is the study of the diversity of organisms and their evolutionary relationships.

Taxonomy is the science of classifying and naming organisms based on their characteristics and evolutionary relationships.

In biology, characters are heritable traits or features of an organism used for identification and classification.

A clade is a group of organisms that includes a common ancestor and all its descendants.

Synapomorphies are shared derived traits that are present in an ancestor and all its descendants, used to determine evolutionary relationships within a clade.

Sister clades are groups of organisms that share an immediate common ancestor and are each other's closest relatives.

A monophyletic group, or clade, includes a common ancestor and all its descendants.

A paraphyletic group includes a common ancestor and some, but not all, of its descendants.

A polyphyletic group includes organisms from different ancestors, not sharing a common ancestor.

Radial Symmetry: Body parts are arranged around a central axis, like in jellyfish and starfish.

Bilateral Symmetry: The body has a left and right side that are mirror images, like in humans and most animals.

Asymmetry

The oral surface is the side of an organism where the mouth is located.

The aboral surface is the side of an organism opposite to the mouth.

The endoderm is the innermost layer of true tissue

The mesoderm is the middle layer of true tissue

The ectoderm is the outermost layer of true tissue

2 tissue layers

3 tissue layers

Metazoa includes all multicellular animals.

Eumetazoa are animals with true tissues, including all major animal groups except sponges.

A coelom is a body cavity lined fully by mesoderm tissue.

Acoelomates lack a coelom, or body cavity.

Pseudocoelomates have a body cavity not fully lined by mesoderm tissue (no Coelom).

Coelomates have a body cavity fully lined by mesoderm tissue.

Protostomes are animals where the mouth develops from the blastopore.

Deuterostomes are animals where the anus develops from the blastopore.

A blastula is an early stage of embryonic development in animals, characterized by a hollow ball of cells.

A blastopore is the opening that forms during early embryonic development.

Cilia are tiny, hair-like structures on the surface of cells that help with movement and sensory functions.

Flagella are long, whip-like structures that help cells move. They are found in both prokaryotic and eukaryotic organisms.

Phytoflagellates are flagellated protists that can photosynthesize, like algae.

Zooflagellates are flagellated protists that feed on other organisms.

Naked amoebas are amoebas that lack a protective shell or covering. They move and feed using extensions called pseudopodia.

Testate amoebas are amoebas that have a protective shell or covering, called a test.

Ciliates are a group of protists characterized by the presence of hair-like structures called cilia, which they use for movement and feeding.