big bang: evolution Flashcards
define Selection pressures
Environmental factors that influence the survival and reproduction of organisms. Pressures can cause competition for resources, disease, and more. Populations have variations of traits, traits that provide advantages in an environment increase an organism’s chance of survival.
define survival of the fittest
phrases often use to describe process of natural selection. Individuals with traits that make them better suited to their environment are more likely to survive, reproduce and pass the trait on.
define resource availability and how its a factor of natrual selection
availability of resources such as food, water, shelter, and mates is a critical factor in natural selection. Organisms compete for resources, organisms with traits that give them competing advantages acquire the resources
define environmental conditions
environmental conditions include factors like temperature, humidity, altitude, and more influences on natural selection. Different environments have different challenges and opportunities for survival. Organisms that can adapt to environmental conditions high chance to pass on the advantaged trait to their offspring.
define some biological factors
such as genetic variation, mutations, and reproductive strategies are important to natural selection. Genetic variation provides raw materials which natural selectin act upon. Mutations may be beneficial, harmful or neutral.
Reasons for variations in a population
Genetic variations
Arise due to differences in DNA sequences of genes. Can occur through mutations and geneflow (the movement of genes between populations) Mutations are the random changes in DNA sequences which allow new traits to be passed onto offspring causing variations in a population.
Environmental influences can lead to difference in traits due to things like amount of sunlight, temperature and available resources.
Why we need variation in a population.
Variations within a population ensure that some individuals possess traits that may be advantageous in a new or changing environment.
Some organisms may inherit traits that make them resistant to certain diseases providing immunity.
In a genetically diverse population, the loss of a few individuals due to environmental factors or disease is less impactful on the entire population. Lacking genetic diversity would mean they all share similar genetic makeup, being susceptible to the same threats, making the entire population vulnerable to extinction.
How does variation lead to evolution
Variations within a population provide the raw materials for natural selection acts. Through the differential survival and reproduction of individuals with advantageous traits, populations gradually evolve over time. Evolutionary processes, including natural selection, genetic variations, and heritability, result in adaptation of species to their environments.
define genes.
A gene is a specific sequence of DNA located on a chromosome. Genes act as instructions for building and maintaining organisms, determine traits such as eye colour and more. Genes are the basic unit of heredity and are passed from parents to offspring during reproduction.
define Alleles
A specific variant of a gene that can be found at a specific location on a chromosome. Alleles vary, resulting in different forms of a particular trait. Alleles can be dominant or recessive. Dominant alleles mask the effect of recessive alleles when present in a heterozygous individual. The combination of alleles an individual carries (genotype) influences its observable traits (phenotype)
define Mutations
Mutations are random changes in DNA sequence. Mutations can be neutral, harmful or beneficial. Mutations are crucial for genetic diversity and evolution but can also cause genetic disorders.
what is Evidence of evolution
fossils, cladograms and biogeography.
Divergent and convergent evolution, comparative anatomy (homologous, analogous, and vestigial structures
define geneflow
the transfer of genetic material from one population to another within the same species. This occurs when individuals from different populations interbreed and exchange genetic information. Geneflow allows for increase in genetic diversity, homogenization, and adaptation as it can introduce advantageous traits form one population to another. Over time, geneflow can counteract the effects of genetic drift and help maintain genetic diversity within a species
define Genetic drift:
refers to the random fluctuations in allele frequencies within a population from one generation to another. More random in smaller populations usually. Can lead to losing genetic diversity as allele frequencies drift away from the original values over generations.
