Unit 7

species

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

fertile offspring

capable of producing viable offspring

reproductively isolated

when a group of organisms is prevented from interbreeding with other groups

Pre-zygote barriers

mechanisms that prevent mating or fertilization between species

post-zygote barriers

mechanisms that occur after fertilization, preventing the development of viable or fertile offspring.

Habitat isolation

Two species might prefer different habitats and thus be unlikely to encounter one another

temporal isolation

Two species might reproduce at different times of the day or year and thus be unlikely to meet up when seeking mates

Two species might have different courtship behaviors or mate preferences and thus find each other "unattractive"

Behavior isolation

Two species might produce egg and sperm cells that can't combine in fertilization, even if they meet up through mating.

Gametic isolation

Two species might have bodies or reproductive structures that simply don't fit together.

Mechanical isolation

Reduced hybrid fertility

The condition where hybrid offspring are sterile and cannot reproduce, preventing gene flow between the parent species.

Reduced Hybrid Viability

(survivability) Parents have incompatible genetics and the hybrid offspring fails to develop

speciation

The evolutionary process by which populations evolve to become distinct species, often due to reproductive isolation.

sexual selection

The process by which certain traits increase an individual's chances of reproducing based on preference by one sex for certain characteristics in individuals of the other sex.

Allopatric speciation

when two different populations are living in different geopgraphic regions, which prevent sgene flow and thus speciation occurs when they are geographically isolated.

Sympatric speciation

Occurs when two different populations living in the same environment and different isolation mechanisms prevent gene flow

Punctuated equilibrium

Evolution occurs after a long period of stasis (a period of little to no change) and followed by a rapid bursts of speciation

Gradualism

The theory that evolution occurs slowly and steadily over time, with gradual changes leading to speciation.

divergent evolution

populations become seperated by geographic barriers and evolve indepedntly into their own species. Different habitats and become more different over time. Same common ancestor

convergent evolution

the process by which unrelated species evolve similar traits or adaptations due to similar environmental pressures, despite having different ancestors.

adaptive radiation

A type of divergent evolution where a group of organisms quickly diverge into new species. Different niches are occupied, leading to a rapid evolution of diversity.

It is possible for complex molcules to be built from inorganic molecules

origins of life

Extinction

can be caused by catastrophic changes to an ecosystem such as solar flares, rising seal levels, volcanic eruptions, or asteroid impacts

Human activity that can increase extinction

Habitat loss, climate change, habitat degradation, pollution, and poaching

High biodiversity

high levels of speciation and low extinction

Low biodiversity

low levels of specification and high extinction

Niche

describes a role of an organism in an evironment; producer, decomposer, scavenger, consumer

Evidence for common ancestry in Eukaryotic

linear chromosomes, membrane bound organelles, and Genes that contain introns

Membrane bound organelles

Shown in Mitochondria and chloroplasts; have double membrane, endosymbiotic theory, and have ribosomes.

endosymbiotic theory

the hypothesis that eukaryotic cells evolved through a symbiotic relationship between different species of prokaryotes, leading to the formation of organelles like mitochondria and chloroplasts.

Linear Chromosomes

Found in all Eukaryotes. It differs from prokaryotic genomes (circular chromosomes ).

What is an Introns

non-coding sequences of DNA within a gene that are removed during RNA splicing.

Intron for common ancestry

Found in all eukaryotes.

Genomic changes

Changes in DNA and Cell divison and environmental disruptions

Continous change in fossil records

Transition fossils can show the evolutionary changes as one groups evolve into another

Resistance to various chemicals

Resistance can show evolutionary changes in terms of new mutations

Fitness

The ability of an organism to reproduce

Pathogens

infectious agent that produce dieases, evolves, can become chemically compatible with its host, and can change phenotypes.

Viruses

They evolve rapidly

Virus Recombination

two different viruses swap genetic material (DNA or RNA) when they have hosted the same cell to create a new viral strain, potentially leading to new characteristics or abilities.

Random mutation

A change in DNA sequence

Macroevolution

large scale evidence for evolution: anatomy, embryology, molecular biology, biogeography, and fossils.

homologous

variation in a structure that was present in a common ancestor

analogous

structures that evolved independently in different species due to similar environmental conditions/selective pressures

evidence 1- molecular biology

DNA sequence comparisons can show how different species are related.

evidence 2- biogeography

These patterns provide clues about how species, both alive and extinct, are related to each other

evidence 3- fossils

are preserved remains, impression, or trace of once living organisms from the past, it tells us age/geographical data

evidence 4 - anatomy/embryology

Anatomical features shared between organisms (including ones that are visible only during embryonic development) can indicate a shared evolutionary ancestry

vestigial structure

A reduced feature that serves little to no purpose for the organism; for example; the human tailbone

Biochemical evidence

A comparison of DNA nucleotide sequences and/or protein amino acid sequences provides evidence for evolution and common ancestry

True or False: Analogous features is convergent evolution

True

reduction of isotope - like carbon 14

is a method used in radiometric dating to determine the age of organic materials by measuring the decay of carbon-14 isotopes.

Phylogeny

the evolutionary history and relationships among species or groups of organisms.

cladogram

a diagram based on shared characteristics.

monophyletic

describing a group of organisms that includes an ancestor and all its descendants, forming a clade.

Paraphyletic

describing a group of organisms that includes an ancestor but not all of its descendants, resulting in an incomplete clade.

polyphyletic

diagram that represents evolutionary relationships among organisms. Phylogenetic trees are hypotheses, not definitive facts. A group of organisms that does not include the most recent common ancestor of the members, typically formed from multiple clades.

nodes on a phylogenetic tree

They tell use the age of the most recent or less recent common ancestor.

branch on a phylogenetic tree

refers to the line representing the evolutionary pathway between two nodes, showing the relationship between different lineages.

root on a phylogenetic tree

the common ancestor of all organisms in the tree, serving as the starting point for the evolutionary relationships depicted.

Taxonomy

the science of classifying organisms into groups based on their evolutionary relationships and characteristics.

What tells you how closely related two species are

two species are more related if they have a more recent common ancestor and less related if they have a less recent common ancestor.

polytomy

a branch point in a phylogenetic tree where three or more descendant groups emerge, indicating uncertain relationships.

what can phylogenetic trees not tell us

we organize species into nested groups based on shared derived traits (traits different from those of the group's ancestor).it does not tell us the exact timing of evolutionary events or speciation.

derived traits

traits that evolved within a group and differ from the ancestral trait.

In terms of DNA of relatedness

• A larger number of differences corresponds to less related species

• A smaller number of differences corresponds to more related species

Genomic changes

Changes in DNA and Cell divison and environmental disruptions

Continous change in fossil records

Transition fossils can show the evolutionary changes as one groups evolve into another

Resistance to various chemicals

Resistance can show evolutionary changes in terms of new mutations

Fitness

The ability of an organism to reproduce

Pathogens

infectious agent that produce dieases, evolves, can become chemically compatible with its host, and can change phenotypes.

Viruses

They evolve rapidly

Virus Recombination

two different viruses swap genetic material (DNA or RNA) when they have hosted the same cell to create a new viral strain, potentially leading to new characteristics or abilities.

Random mutation

A change in DNA sequence

Evidence for common ancestry in Eukaryotic

linear chromosomes, membrane bound organelles, and Genes that contain introns

Membrane bound organelles

Shown in Mitochondria and chloroplasts; have double membrane, endosymbiotic theory, and have ribosomes.

endosymbiotic theory

the hypothesis that eukaryotic cells evolved through a symbiotic relationship between different species of prokaryotes, leading to the formation of organelles like mitochondria and chloroplasts.

Linear Chromosomes

Found in all Eukaryotes. It differs from prokaryotic genomes (circular chromosomes ).

What is an Introns

non-coding sequences of DNA within a gene that are removed during RNA splicing.

Intron for common ancestry

Found in all eukaryotes.

Macroevolution

large scale evidence for evolution: anatomy, embryology, molecular biology, biogeography, and fossils.

homologous

variation in a structure that was present in a common ancestor

analogous

structures that evolved independently in different species due to similar environmental conditions/selective pressures

evidence 1- molecular biology

DNA sequence comparisons can show how different species are related.

evidence 2- biogeography

These patterns provide clues about how species, both alive and extinct, are related to each other

evidence 3- fossils

are preserved remains, impression, or trace of once living organisms from the past, it tells us age/geographical data

evidence 4 - anatomy/embryology

Anatomical features shared between organisms (including ones that are visible only during embryonic development) can indicate a shared evolutionary ancestry

vestigial structure

A reduced feature that serves little to no purpose for the organism; for example; the human tailbone

Biochemical evidence

A comparison of DNA nucleotide sequences and/or protein amino acid sequences provides evidence for evolution and common ancestry

True or False: Analogous features is convergent evolution

True

reduction of isotope - like carbon 14

is a method used in radiometric dating to determine the age of organic materials by measuring the decay of carbon-14 isotopes.

Evolution

"descent with modification," a process in which species change and give rise to new species over many generations.

Adaptation

The process of changing to better fit an environment.

Natural selection

Nature’s way of selecting an organism because their trait favors the environment and they tend to survive and reproduce.

Variation

The differences between individuals within a population, which can lead to evolution through natural selection.

biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

Evolution

"descent with modification," a process in which species change and give rise to new species over many generations.

Adaptation

The process of changing to better fit an environment.