u3 Flashcards
What does Transformism refer to?
Transformism refers to the whole group of legends that talk about fabulous transformations.
What is the main idea of Creationism?
According to creationism, nature and the species are unchangeable and finished products since they were created.
What does Catastrophism attempt to explain?
Catastrophism attempts to explain the existence of fossils and suggests that geological catastrophes caused extinctions followed by new creations.
What is Lamarckism?
Lamarckism is the theory that all species change/evolve continuously and gradually throughout existence.
What are the three main tenets of Lamarckism?
- Tendency to complexity
- Adaptations
- Inheritance of acquired characters
What does the ‘use and disuse hypothesis’ state?
The hypothesis states that necessity provokes the appearance of new organs, while unused organs disappear.
What is the significance of the giraffe case in Lamarckism?
Lamarck used the giraffe case to illustrate how acquired characteristics, like longer necks, could be passed to descendants.
Who are the main proponents of Darwinism?
Charles Darwin and Alfred Russel Wallace.
What did Darwin’s travels on the H.M.S. Beagle contribute to his theories?
Darwin observed diverse species and their adaptations, leading him to formulate his theory of evolution.
What are the main principles of Darwin’s theory of evolution?
- High reproductive rate of living organisms
- Variability of descendants
- Natural selection
What is natural selection?
Natural selection is the process where individuals better adapted to their environment are more likely to survive and reproduce.
What is Neo-Darwinism?
Neo-Darwinism, or synthetic evolution theory, combines classical Darwinism with modern genetics to explain evolution.
What is a gene pool?
A gene pool is the combined genetic information of all members of a particular population.
What are the two main sources of genetic variation?
- Mutations
- Gene shuffling
What does the Hardy-Weinberg principle state?
Genetic equilibrium occurs when allele frequencies remain constant under specific conditions.
What conditions must be met for Hardy-Weinberg equilibrium?
- No mutations
- Random mating
- No natural selection
- Extremely large population size
- No gene flow
What is speciation?
Speciation is the process by which a population forms a new species that cannot reproduce with the original population.
What is allopatric speciation?
Allopatric speciation occurs when a population is divided by a geographic barrier, leading to the formation of a new species.
What is sympatric speciation?
Sympatric speciation occurs when a species diversifies in the same geographic area through mechanisms that impede breeding.
What are pre-zygotic mechanisms?
Pre-zygotic mechanisms are barriers that prevent fertilization from occurring.
What is extinction?
Extinction is the process by which a species ceases to exist.
What is biodiversity?
Biodiversity refers to the variety of life in a particular habitat or ecosystem.
What are the three parts of biodiversity?
- Species diversity
- Genetic diversity
- Ecosystem diversity
What role does evolution play in biodiversity?
Evolution drives speciation, leading to the emergence of new species and increased biodiversity.
What is the impact of biodiversity on ecosystems?
High biodiversity contributes to ecosystem resilience and stability.
What percentage of medicine comes from plants?
40% of medicine comes from plants.
What is an example of a plant that has contributed to cancer treatment?
Rosy periwinkle has chemicals that fight cancer, significantly improving survival rates for childhood leukemia.
What percentage of the human population’s food supply relies on just three staple plants?
Over half of it’s food supply relies on rice, corn, and wheat.
What role do insects play in agriculture?
Insects pollinate crops, help in weed control & in insect pest control.
What are ecosystem services?
Important environmental functions that organisms within ecosystems provide.
Define keystone species.
Species so important to the functioning of ecosystems that the whole ecosystem would collapse if they disappeared.
What percentage of medicine comes from plants?
40%.
By what year will 25% of all species that lived on Earth in 1900 be gone?
By 2100.
What is the single greatest threat to biological diversity?
Habitat Loss.
Fill in the blank: Some species are particularly prone to extinction if their habitat is altered due to their _______.
[Small, localized range].
What are the four main reasons humans are contributing to the current mass extinction?
- Habitat Loss
- Exotic Species (Biotic Pollution)
- Pollution
- Overexploitation.
What human activity is responsible for 85% of plant and animal extinctions?
Habitat Loss.
True or False: Exotic species usually have natural predators in their new environments.
False.
What is the impact of pollution on natural areas?
It can degrade natural, undisturbed wilderness areas.
Give an example of a species that has been impacted by overexploitation.
African Elephants.
What is the ecosystem approach to conservation?
Protecting entire ecosystems to save many species at once.
What do botanical gardens serve as?
Storehouses for a variety of species.
What is the role of germ-plasm banks?
They store seeds and sperm/egg in controlled environments for future use.
Which species requires large territories and was nearly extinct in the late 1980s?
California Condor.
Fill in the blank: The decline of large stands of forests and death of many organisms in freshwater lakes is an example of _______.
[Acid Rain].
What is a significant characteristic of island species that makes them vulnerable?
They are often endemic and evolved in isolation.
What is a common consequence of habitat destruction on reproductive success?
It can disrupt breeding patterns.
What happens when a population density and size fall below a certain minimum level for reproductive success?
The population declines even further.
What type of food do panda bears primarily eat?
Bamboo.
What can we study to understand an animal’s evolutionary history?
The fossil record
The fossil record shows that the whale evolved from a land-dwelling creature.
What does comparative anatomy help us determine?
How living species evolved
Homologous structures suggest descent from a common ancestor.
What are homologous structures?
Structures made up of similar parts that serve different purposes
Example: The forelimbs of mammals.
What are analogous structures?
Structures that have the same function but do not come from a common ancestor
Example: The wings of bats and birds.
What does comparative embryology compare?
Living species at the embryo stage
This helps identify shared traits that may not appear in adulthood.
Define vestigial structure.
A trait that was once necessary but is no longer needed
Example: The human tail bone.
How can DNA comparisons help in understanding evolution?
By estimating how long it has been since related species diverged from a common ancestor.
What is biogeography?
The study of the distribution of species and ecosystems in geographic space and through geological time.
What is adaptive radiation?
The process by which organisms diversify rapidly into a wide variety of forms to adapt to different environments
Example: Darwin’s finches on the Galápagos Islands.
What is Darwin’s theory of evolution based on his observations?
- Organisms change over time. 2. Evolution occurs by natural selection.
What does natural selection explain?
The great diversity of life
Traits best suited to the environment prevail over time.
Define fitness in the context of natural selection.
How well an organism can get food and produce fertile offspring.
What is artificial selection?
Humans favoring specific traits in a population or species
Example: The domestication of dogs from wolves.
List some economic benefits of biodiversity.
- Wide pool of genetic variation in wild species
- Products like timber and fibers
- Indicator species for environmental toxins
- Source of prescription drugs
- Inspiration for engineering and technology.
What are ecosystem services provided by plants and algae?
- Remove carbon dioxide and add oxygen
- Improve soil quality
- Purify water
- Pollinate flowering plants
- Control pests.
Who is considered the father of genetics?
Gregor Mendel.
What is heredity?
The passing of traits from parent to offspring.
Define genotype.
The genetic makeup of an organism.
Define phenotype.
The physical appearance of an organism.
What does the principle of dominance state?
Some alleles are dominant and others are recessive.
What is a Punnett Square used for?
To predict the phenotype and genotype of offspring.
What is incomplete dominance?
A situation where the heterozygous phenotype is intermediate between both homozygous phenotypes
Example: Pink flowers.
What is codominance?
Both alleles contribute to the phenotype; neither allele is dominant
Example: Roan cattle.
What are mutations?
Changes in the nucleotide sequence of DNA.
What is nondisjunction?
The failure of homologous chromosomes to separate properly during meiosis.
What is Down’s Syndrome caused by?
Nondisjunction in chromosome 21.
Define polyploidy.
The condition of having more than two complete sets of chromosomes.
What are the effects of polyploidy in plants?
- Larger size
- Increased yields
- Sterility in some cases.
What do mutations lead to in terms of evolution?
- Accumulation of many small mutations
- One large mutation with a large effect.
