Evolution Review

idk..

evolution

the process by which species change over time through genetic variation and natural selection

most recent common ancestor

the most recent individual from which all species in a particular group are directly descended.

Fossils (Evolution)

preserved remains or traces of organisms from the past, providing evidence of historical life forms and their evolution.

Biogeography (Evolution)

the study of the distribution of species and ecosystems across geographic locations, providing insight into the effects of evolution and environmental factors on biodiversity.

Homology: Comparative Anatomy (Evolution)

the study of similarities in structure and anatomy among different species, indicating common ancestry and evolutionary relationships.

Homology: Embryology (Evolution)

the study of similarities in embryonic development among different species, revealing insights into common descent and evolutionary processes.

Homology: Molecular Genetics

the study of similarities in DNA sequences and molecular structures across different species, providing evidence for shared ancestry and evolutionary relationships.

Lamarckianism

an evolutionary theory suggesting that organisms can pass on traits acquired during their lifetime to their offspring, leading to gradual evolutionary change

Why is Lamarckianism wrong?

B/c implies that organisms change within a lifetime, not generations

Artificial selection

human-driven process in which humans identify traits in animals, and choose which animals with said traits will reproduce to pass said traits onto offspring

Overproduction (Natural Selection)

Species producing more offspring than the environment can support

Variation (Natural Selection)

Differences in physical traits, behaviors, or genes among individuals within a population

Heritability (Natural Selection)

Dictates how well advantageous traits pass from parents to offspring

Selective Pressure (Natural Selection)

external environmental factors that make certain physical traits or behavioral traits more factorable for survival and reproduction

Differential reproductive success

some individuals in a population produce more surviving offspring than others

Adaptation

any heritable trait or behavior that helps an organism survive or reproduce in its environment

Evolutionary Fitness

an organism’s ability to pass its genetic material on to the next generation

Role of randomness (Natural Selection)

genetic mutations (changes in DNA), genetic drift (natural disasters, bottlenecks, or a chance with a predator)

Individuals….

don’t evolve or adapt; populations

Adaptations…

aren’t perfect solutions

Genes (Evolution)

Evolution in genetic level —> change in allele frequencies within a population

Gene Pool

Complete set of all alleles for all genes in an given population

Allele

Specific variant of a gene

Gene

basic unit of DNA

Allele frequency

The proportion or rate at which alleles appear in a gene pool

Microevolution

Evolutionary change measured by tracking shifts in allele frequencies

Pinky (Microevolution)

Genetic Drift — (Small populations allow chance events to drastically alter gene pools)

Bottleneck (Genetic Drift)

sharp reduction in a population’s size caused by natural disasters, disease, or human actions

Founder effect (Genetic Drift)

a small group of individuals break away from a larger parent population to establish a new, isolated colony

Middle Finger (Microevolution)

Mutation — change in an organism’s DNA sequence that serves as the ultimate source of new genetic variation in a population

Ring Finger (Microevolution)

Nonrandom mating — individuals (more or less likely) to mate based on genotypes or geographic proximity

Pointer Finger (Microevolution)

Gene flow — transfer of genetic material from one population to another (animals migrate from one area to another w/ introducing new alleles and traits into the receiving population)

Thumb (microevolution)

Natural selection — the process where organisms with traits better suited to their environment tend to survive, reproduce, and pass those advantageous genetic characteristics on to future generations

Convergent Evolution

the independent evolution of similar traits or structures in unrelated lineages as an adaptation to similar environmental pressures

Speciation

evolutionary process by which ancestral population splits into two or more genetically distinct, reproductively isolated descendant species

Bacteria

Single-celled prokaryotes —> cell nucleus

Archaea

Single-celled prokaryotes lacking peptidoglycan (rigid mesh-like polymer made of sugars) —> no cell nucleus

Eukarya

Organisms with complex cells containing a true nucleus and membrane-bound organelles (animals, plants, fungi)

Prokaryotes

Microscopic, single-celled organisms that do not have a cell nucleus

Cell nucleus

organelle found in eukaryotic cells that stores DNA

Eukaryotes

organisms whose cells contain a distinct nucleus and other compartments called organelles

Animals

sits within the Eukaryota domain (lack cell walls and reproduce sexually)

Plants

sits within the Eukaryota domain (containing cells walls and use the process of photosynthesis to make their own food)

Fungi

sits within the Eukaryota domain (rigid cell walls and use digestion and absorption to get food)

vitamin D-folate hypothesis

human skin color (evolution) —> balancing act to protect circulating folate from destruction while allowing enough ultraviolet radiation to synthesize vitamin D3

Skin Color (Evolution)

1. Early human ancestors (developed dark skin —> natural sunscreen)

2. High levels of UV radiation break down folate (less folate —> severe health outcomes)

3. Human populations went out of Africa (heavy pigmentation blocked radiation)

4. Lighter skin —> let UV come into to synthesize vitamin D3

Folate (Trade-off)

Fragile & light-sensitive (degrades rapidly under intense UVA & UVB exposure -—> darker skin shields it)

Vitamin D3 (Trade-off)

Requires absorption of UV rays, with lighter skin reducing the barrier in low-light environments