Understanding Evolution and Bipedalism in Hominins

Evolution

Poorly understood scientific concept in public perception.

Natural Selection

Process where favorable traits enhance survival.

Common Ancestor

Shared ancestor of humans and chimpanzees.

Darwin's Limitations

Lacked knowledge of mutation and DNA.

Scientific Method

Systematic testing of hypotheses and self-correction.

Hypothesis

Testable predictions about phenomena.

Genotype

Genetic makeup of an organism.

Phenotype

Observable physical characteristics of an organism.

Alleles

Different versions of the same gene.

Homozygous

Same alleles at a locus.

Heterozygous

Different alleles at a locus.

Mendelian Traits

Traits controlled by a single gene.

Pleiotropy

Single gene influences multiple traits.

Polygenic Traits

Traits influenced by multiple genes.

Microevolution

Change in allele frequencies within populations.

Macroevolution

Formation of new species over time.

Mutation

Change in DNA sequence affecting traits.

Galapagos Finches

Example of natural selection in action.

Antibiotic Resistance

Bacteria evolving to survive antibiotic treatment.

Reproductive Success

Survival and reproduction of favorable traits.

Genetic Variation

Diversity in alleles within a population.

Dominant Allele

Expressed trait in heterozygous individuals.

Recessive Allele

Trait masked by dominant allele.

Phenylthiocarbamide (PCT)

Taste sensitivity trait controlled by alleles.

Pennett Square

Tool for predicting offspring genetic traits.

Selective Pressure

Environmental factors influencing survival and reproduction.

Fossil Record

Historical evidence of past life forms.

Biological Diversity

Variety of life forms in an ecosystem.

Gene Flow

Transfer of genes between populations across locations.

Genetic Drift

Random changes in allele frequencies by chance.

Founder Effect

Genetic drift occurring in small founding populations.

Polydactyly

Condition of having more than five fingers/toes.

Biological Species Concept

Species defined by reproductive isolation mechanisms.

Hybridization

Interbreeding between different species resulting in hybrids.

Recognition Species Concept

Species identified by specific mate recognition systems.

Morphology

Study of the form and structure of organisms.

Morphospecies

Species defined by distinct morphological characteristics.

Chronospecies

Species defined by significant temporal separation.

Mosaic Evolution

Different traits evolve at different rates in organisms.

Hominin

Group including modern humans and their ancestors.

Obligate Bipedalism

Walking on two legs as the primary locomotion.

Facultative Bipedalism

Ability to walk on two legs but not exclusively.

Foramen Magnum

Skull opening for spinal cord, indicates bipedalism.

Pelvis Adaptation

Changes in pelvis shape for upright walking.

Gluteal Muscles

Muscles aiding in stability and movement in bipeds.

Thermoregulation

Regulation of body temperature through posture.

Energy Efficiency

Reduced energy cost of movement in bipedalism.

Obstetric Dilemma

Challenge of childbirth due to bipedal adaptations.

Lovejoy's Hypothesis

Early hominids exchanged food for reproductive access.

Sexual Dimorphism

Differences in appearance between male and female species.

Bipedalism Evidence

Footprints and skeletal changes indicating upright walking.

Cranial Changes

Skull adaptations associated with bipedal locomotion.

Skeletal Implications

Physical changes in the body due to bipedalism.

Speciation

Process by which new species arise from existing ones.