Natural Selection - Overall Study Flashcards
Define selective agent
The environmental factor that acts upon a population
Define selection pressure
The effect of a selective agent
Give examples of a selective agent
Biotic factor: Bacterial infection, competitor, predator
Abiotic factor: temperature, water, soil nutrients, fire
What are the three steps of speciation?
- Variation
- Isolation
- Selection
Define variation in terms of natural selection
Within a population there is a difference in DNA among individuals
What was the main idea behind evolution?
A species can change over many generations, potentially forming new species
What is a generation?
The time between the birth of an individual and when the individual produces offspring
What does natural selection affect within a population?
It affects what traits are considered desirable and what is passed down through generations
Give an example of a selection pressure
Coat colour change of mice because of the owl selection pressure
Define analogous structures
Analogous structures are bone structures that serve the same function but don’t have the same amount of bones or structure
Define homologous structures.
Homologous structures are bone structures that have the same amount of bones and same arrangement, but don’t serve the same function
How does the fossil record prove evolution is true?
The fossil record shows the changes in species and transitional forms over time which proves evolution to be true.
Provide examples of animals that are often artificially selected.
Dogs, cats, budgerigars (budgies)
What features do primates have?
Most have grasping hands, nails rather than claws and forward-facing eyes
What causes variation?
Differences within genes
TRUE or FALSE
Sexual selection is considered an example of natural selection
True
Define cytochrome c
A protein found in all living things
Define comparative anatomy
Comparative anatomy is the study of comparing physical structures of a species to another
What did Charles Darwin theorise during his observation of the Galapagos finches?
The finches changed to suit their environment. The beaks changed to suit their food source
Define natural selection
The way a species changes characteristics depending on what their natural environment demands
Define artificial selection
The process of humans choosing to breed particular organisms with desirable features.
Also called selective breeding
How was it indicated that other species of human-like animals existed?
Fossils
What is a species?
The smallest unit of biological classification. Able to interbreed without complications & produce fertile offspring.
What is sexual selection?
What is considered more sexually attractive within a species and therefore more likely to reproduce.
Which animals are most like humans?
Gorillas & Chimpanzees
What is a selective breeding method?
Cross-breeding
Inbreeding
Charles Darwin predicted the best place to find fossils of human origins. Where?
Africa
What is variation?
Natural differences within a population
In what order did homo species exist?
- Australopithecus
- Homo Habilis
- Homo Ergaster / Erectus
- Homo Heidelbergensis
- Homo Neanderthalis & Homo Sapiens
What is hybridisation?
When two very similar species produce offspring called hybrids
What health problems do hybrids often have?
They are normally infertile and come with a wide range of health issues
Give an example of a hybrid
Liger
Mule
Hinny
How long have Homo Sapiens been around?
About 200,000 years
Give an example of a homologous structure
The limbs of vertebrates
Cat, human, bat, bird, horse, whale
Give an example of an analogous structure
Wings: bird, butterfly, bat
Swimming: Shark, penguin, dolphin
What is the biological classification system that we still use today called?
Linnaean classification system
Define ecological niche
The role a species has in its environment eg: food, behaviours, reproduction
How does cytochrome c prove evolution?
By comparing how many amino acids are in the same position on the cytochrome c protein chain it proves how closely related two species are.
What is the science of classifying animals called?
Taxonomy
Define competition in terms of natural selection
There are more offspring per generation than can survive, individuals will have to out compete each other
Define inheritance in terms of natural selection
A trait can be passed down on through DNA, therefore, offspring will inherit the traits of their parents
What are the four main principles of natural selection?
- Variation
- Competition
- Survival of the fittest
- Inheritance
What is cross-breeding?
Crossing two individuals with desirable features in the hopes the offspring will show a combination of the features.
What is inbreeding?
Related individuals mate
What are the issues with inbreeding?
Often causes health issues, deformities, sterility and genetic disease
Define genotype
The genetic make up of an individual
Define phenotype
The particular characteristics of an individual
What is the modern definition of natural selection?
The change of a particular genetic make up due to environmental selection over many generations
Define cladistics
The field that classifies life based on DNA sequencing
Define convergent evolution
When two species develop a similar trait to serve a specific function without breeding.
Define divergent evolution
Two populations of the same species are isolated from each other and evolve different traits until they are no longer the same species
What is a key feature that animals have to have to be classified into the sub-tribe with human?
Walking upright on two legs
What is speciation?
The process by which one species splits into two or more separate species.
What are the three eras of the geological time scale?
Paleozoic, Mesozoic, and Cenozoic
What class are humans classified into?
Mammalia
Define survival of the fittest in terms of natural selection
Individuals with traits that are better adapted to their environment will survive and reproduce, whereas individuals without those traits will die
What are the categories of Linnaean Classification?
(In order) Kingdom, Phylum, Class, Order, Family, Genus, Species
What family are humans classified into?
Homonidae
What is the ‘Out of Africa’ model?
A model that proposes the idea that all humans originated from Africa
When is it estimated that humans left Africa?
Around 60,000 years ago
What evidence supports the ‘Out of Africa’ model?
By analysing the DNA of hundreds of thousands of people, scientists were able to trace their ancestry back to a small group in Africa
Within the skulls of likely members of the human family, what changes have occurred during evolution?
- Face becomes flatter
- Cranium enlarges
- Lower jaw shortens
- Cranium is more rounded
- A chin develops
- Cranial capacity increases
- Forehead becomes vertical
