Evolution Flashcards
What is the Charles Darwin theory?What does speciation mean?
All living things have a common ancestor.
Speciation is when populations evolves to become a new species.
What are species?
A group of organisms that can interbreed and produce viable fertile offspring under natural conditions.
What is adaptive radiation?
Rapid diversification from a common ancestor.
Usually occurs when a species encounters NEW ENVIRONMENTAL OPPOTUNITIES
What are the new environmental opportunities
Colonisation of new habitats
Extinctions of competitors
What are the principles of natural selection?
Variation
Selective pressure
Differential Survival and Reproduction
Heritability
What does variation mean?
Individuals in populations exhibit variation in their traits which is inherited.
What is selective pressure?
The environment presents challenges or pressures that influence an organism ability to survive and reproduce.
What is differential survival and reproduction?
Individuals with traits that enhance their survival and reproduce success more likely to pass traits to the next generation.
What is convergent evolution?
The process by which unrelated species independently evolve similar traits or adaptations in response to similar selection pressures.
What is divergent evolution?
The process by which a single ancestral species evolves two or more distinct descendent species, each with unique traits and adaptations.
What is co- evolution?
Two species evolve together due to their close relationship. When one evolves, so does the other.
What is biodiversity?
Biodiversity is the variety and variability of living organisms present in a particular habitat or ecosystem.
What is species diversity?
This refers to the variety and abundance of different species within a particular habitat or ecosystem.
What are the three levels measured in biodiversity?
Species Diversity
Genetic Diversity
Ecosystem Diversity
What is ecosystem diversity?
This refers to the variety and abundance of different species within a particular habitat or ecosystem.
What is genetic diversity?
The variation in genes within a species.
Genetic diversity is essential for adaptation and the long-term survival of species as it allows for evolutionary change.
What are the factors that influence genetic diversity?
Mutation
Gene Flow
Genetic Drift
Natural Selection
What is a mutation?
Changes that occur in an organism’s DNA sequence.
What is gene flow?
The movement of genes between populations.
Occurs when individuals migrate from one population to another and interbreed with individuals from the recipient population.
Introduces new genetic variation into a population, increasing genetic diversity.
What is genetic drift?
The random fluctuation of allele frequencies within a population over time.
More common in small populations.
Can result in the loss or fixation of certain alleles.
What is the founder effect?
Occurs when a small group of individuals establishes a new population in a new area geographically isolated from the original population.
What is the bottleneck effect?
Occurs when a population undergoes a catastrophic event
Surviving individuals have limited genetic diversity and certain alleles may be lost altogether. Even as the population recovers, there’s a chance diversity will still be limited.
What are the factors affecting biodiversity?
Habitat loss and fragmentation
Climate change
Pollution
Invasive species
Overexploitation and illegal wildlife trade
Pollution
Human population growth
Conservation efforts
How can isolation lead to speciation?
Reproductive isolation occurs when a population splits into two groups and the two populations no longer interbreed. When populations become reproductively isolated, they can evolve into two separate species.
What are homologous structures?
- similar structures in organisms with shared ancestry
- these animals may share the same common ancestor but not have the same structure
- different functions
- arises with divergent evolution
What are analogous structures?
-structures with similar functions in different species but don’t share a common ancestor.
- arises with convergent evolution
how to read a phylogenetic tree?
The tree’s root represents the ancestral lineage, and the branches’ tips represent the ancestors’ descendants. As you move from the root to the tips, you are moving forward in time. When a lineage splits (speciation), it is represented as branching on a phylogeny.
