Chapter 8.1 Living Things Change and Diversify ✓ Flashcards
Define species
A group of similar organisms capable of breeding and whose offspring are also fertile
Define evolution
The process of cumulative, gradual, inheritable change in a population over many generations
Define theory
An explanation that has not been proven as fact but is supported by evidence.
Define adaptation
An evolved structural, physiological or behaviour characteristic of an organism that increases its chance of survival and reproduction in a particular environment.
Define ancestor
A species from which other species have evolved
Define common ancestor
An ancestor that is shared by different species
Define phylogeny
Evolutionary relationships that exist between species, often expressed in a tree-like diagram.
What does a phylogeny diagram seek to reconstruct?
It seeks to reconstruct the evolutionary history of any given group of organisms, studying the similarities and differences between the,m
What are the five main sources of evidence for the theory of evolution?
-Biogeography (long term studies on life of earth)
-Comparative genomics (genetics)
-Fossil record (palaeontology)
-Comparative embryology ( developmental biology)
-Comparative anatomy
For how long has life existed on Earth?
For approximately 3.5 billion years
Explain the similarities and differences between Lamarck’s theory of transmutation of species by spontaneous generation and Darwin’s theory of evolution by natural selection.
Similarities
-Both theories attempted to explain how species change over time and adapt to their environments
-Both theories involved the idea that species were not fixed and could evolve.
-Both theories proposed that these changes could be passed to future generations leading to a long-term change in population
Differences
-Lamarck’s theory suggested that organisms change during their lifetimes in response to their environment and pass on these acquired characteristics to their offspring
-In contrast, Darwin’s theory of natural selection stated that variation already exists within a population, and individuals with favourable inherited traits are more likely to survive and reproduce. These traits become more common over generations, without organisms needing to ‘develop’ them during their lifetime.
Define Lamarck’s theory of transmutation of species
-Lamarck’s theory of transmutation of species proposed that organisms pass on characteristics they acquire during their lifetimes to their offspring.
-For example, if an organism developed useful behaviour or traits during its life, there would be inherited by its descendants.
-The idea was an early attempted to explain how species change overtime and introduced the concept of adaptation.
Define Darwin’s theory of evolution by natural selection
-Darwin’s theory of evolution by natural selection states that individuals with traits better suited to their environment are more likely to survive and reproduce.
-These favourable traits (alleles) are passed on to the next generation, leading to gradual changes in the population.
Compare the definition of evolution with the theory of evolution
-Evolution refers to the slow, inherited change in a population over many generations
-Theory of evolution explains how evolution happens; through natural selection where individuals with favourable traits survive and reproduce
-So in comparison, the definition tells what evolution is and the theory explains how it works
Explain why evolution is applied to a population, rather than an organism.
Because individuals don’t change their inherited traits during their lifetime. Evolution is the change in the genetic makeup of a population over many generations, not in one organism
