topics covered Flashcards
(19 cards)
Definition of Evolution
Evolution is the process of how living things change over time
Adaptation vs. Evolution:
Adaptation is when a living thing develops traits that help it survive in its environment.
Evolution is where species change over time, often because of adaptations that help them survive and reproduce
Causes of Adaptations & Evolution:
Adaptations: Changes in the environment, Mutations, Natural selection
Evolution: Caused by genetic changes, Genes mixing from migration, Random changes in small groups
Major Evolutionary Theories:
Mutation Theory: Mutations cause sudden changes that lead to evolution.
Darwin’s Theory of Natural Selection:traits better suited to their environment are more likely to survive and reproduce
Modern Evolutionary Synthesis: Combines natural selection with genetics to explain evolution.
Darwin’s Theory of Natural Selection:
traits better suited to their environment are more likely to survive and reproduce
Evidence for Evolution:
Fossil Record: Older fossils are found deeper; newer ones are closer to the surface.
Biogeography: Geographic distribution of species shows common ancestry.
Comparative Anatomy: Homologous (same origin) vs. analogous (same function) structures.
Vestigial Structures: Body parts that have lost function (e.g., human appendix).
Comparative Cytology, Development, and Biochemistry: Similarities in cells, embryos, and DNA.
DNA Analysis: Closely related species share more DNA similarities.
Extinction
Occurs when a species can no longer survive in its environment due to changes or competition.
Mechanisms of Evolution:
Mutation: Genetic changes;Types: substitution, insertion, deletion, frameshift, chromosomal.
Which cause change?: Frameshift, missense, nonsense, and chromosomal mutations
Gene Flow: Movement of genes between populations (like animals migrating and mating)
Genetic Drift: Random changes in gene frequencies (especially in small populations,bottleneck & founder effects).
Non-Random Mating: Choosing mates based on traits (like bright feathers).
Natural Selection: Favorable traits become more common
Types of Natural Selection
Directional Selection: Favors one extreme trait.
Stabilizing Selection: Favors average traits.
Disruptive Selection: Favors both extremes.
Speciation & Factors
Speciation: when one species splits into two or more species and can no longer mate with each other.
Factors: Geographic isolation, mutations, selection, reproductive isolation.
Reproductive Isolation
Pre-Zygotic Barriers: Happen before fertilization – prevent the egg and sperm from joining (e.g., behavioral, temporal isolation).
Post-Zygotic Barriers: Happen after fertilization – the zygote forms but there’s a problem
Bottleneck & Founder Effects
Bottleneck Effect: Happens when a disaster (like a flood, fire, or disease) kills off most of a population.
Founder Effect: A small population forms a new group
Allopatric vs. Sympatric Speciation:
Allopatric: Caused by geographic separation.
Sympatric: Happens without physical separation
Human Influences on Evolution
Poulltion, Artifical selection, habitat distruction, overfishing/overhunting, climate change
Adaptation & Evolution Examples
Adaptation: Camel humps: stores fat for survival, Thick fur on polar bears for cold weather
Evolution: Elephants with smaller tusks becoming more common for poaching, Bacteria evolving due to overuse of antibiotics, finches developing different beak shapes for different food
Definition of a Species
A species is a group of organisms that can mate with each other and produce fertile offspring (offspring that can also reproduce)
Monogenisis, Evidence/Orgins
Monogenesis is the idea that all humans came from a single origin or ancestral group
Evidence: Fossils, DNA similarities, tool use, brain size changes.
Location: Africa.
Differences from Other Primates: Larger brains, upright posture, complex culture and smaller teeth and jaws
Origin of Life & Abiogenesis:
Abiogenesis: Is the idea that life originated from non-living matter.
Hypothetical Steps: Simple molecules form, Molecules join into bigger ones, Molecules organize into cell-like structures, cell membrane forms
Phylogeny & why its useful
Phylogeny is the study of the evolutionary relationships between different species.
Why is it useful?: Shows how traits have changed over time, Helps scientists classify living things more accurately.
