Bio TEST 1, Evolution, Evidence, and Speciation: Key Concepts for Biology

Evolution

Evolution is the process of decent by modifciation. Slective pressures are factors in an enviorment that benefit certains desireable traits over another. There fore due to natural selction, the survial rates of organisms with those desirable traits, species better fit for an enivormtent survie and reproduce at a higher rate, this is evolution

Natural Selection

The overall process by which individuals with certain heritable traits survive and reproduce at higher rates because of those traits.

Selective pressure

A specific environmental factor that causes certain traits to be favored over others, leading to changes in the frequency of those traits.

Direct Observations of Evolution

When we have directly observed evolutionary change in a species in a scientific study.

Homology

When differing species have characteristics with underlying similarities resulting from a common ancestor.

Homologous structures

When anatomical structures in species represent variations on a structural theme that was present in their common ancestor.

Vestigial Structures

Remnants of features that served a function in the organism's ancestors.

Convergent Evolution

When similar features evolve independently in different lineages.

Fossil Evidence

The fossil record documents the pattern of evolution, showing how organisms have changed, gone extinct, and become more complex.

Biogeography

The scientific study of the geographical distributions of species. If lineage branching coincides with continental separation, this provides evidence for evolution.

Species (Biological)

A group of populations whose members can interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.

Reproductive Isolation

The existence of biological factors which prevent members of two species from interbreeding in nature and producing viable, fertile, offspring.

Postzygotic barriers

Barriers that contribute to reproductive isolation after fertilization, leading to hybrid inviability or hybrid sterility.

Allopatric Speciation

The formation of a new species due to geographic isolation between two populations of an original species, which prevents gene flow.

Sympatric Speciation

The evolutionary process where a new species evolves from a single ancestral population while inhabiting the same geographic region, leading to reproductive isolation without any physical separation.

Hybrid Zone

A region where members of different species meet and mate, producing offspring of mixed ancenstry.

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How does molecular biology provide evidence for evolution?

By studying DNA sequences, similarities among different organisms can be identified.

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What defines a species?

A species is an organism that can reproduce and breed with others of the same type.

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What is sympatric speciation?

Speciation that occurs in the same area but involves isolation due to prezygotic or postzygotic barriers.

What are prezygotic barriers?

Barriers that prevent fertilization from occurring before a zygote is formed, such as temporal, habitat, mechanical, and gametic isolation.

What are postzygotic barriers?

Barriers that occur after fertilization, such as the inability of offspring to reproduce.

What is peripatric speciation?

A form of allopatric speciation where one group is smaller than the other.

What is parapatric speciation?

Process where a new species evolves from a continuously distributed population that is not geographically isolated but experiences divergent selection pressures across its range, leading to a hybrid zone and gradual reproductive isolation between contiguous subpopulations. This leads to mating primarily with nearby individuals.

Polyploidy

Extra sets of chromosomes, can also occur when two different species interbreed and produce hybrid offspring

Autopolyploid

An individual that has more than two chromosome sets that are all derived from a single species

Allopolyploid

When various mechanisms can change a sterile hybrid into a fertile