chp 22 descent with modification

evolution

the process by which species accumulate differences from their ancestors as they adapt to different environments over time.

natural selection

a process in which individuals with certain inherited trairs tend to survive and reproduce at higher rates because of those traits

artificial selection

breeding only individuals with desired traits; humans modify this way 

homology 

evolving from the same ancestor,

homologous structures

structures are anatomical resemblances that represent variations on a structural theme present in common ancestor 

analogous structures 

structures are anatomical resemblances that represent variations on a structural theme present in common ancestor 

convergent evolution

a distinct phenomenon where similar features evolve independently in distantly related groups due to independent adaptation to similar environments

biogeography 

the scientific study of the geographic distribution of species, provides support for evolution —> species distribution influenced by continental drift 

what are the 3 broad observations of descent with modification?

the unity of life shared characteristics like DNA and cellular structure,

the diversity of life the vast array of species and their unique adaptations

the adaptive fit of organisms to their environments how species are well-suited to their surroundings

what is evolution as a pattern?

the observable, recurring trends in how species change and diversify over time

• divergent evolution (one species splitting into many)

• convergent evolution (unrelated species developing similar traits)

• co-evolution (species evolving in response to each other).

what is evolution as a process?

the change in the inherited traits of a population over generations.

• driven by genetic drift, natural selection, gene flow, and mutations 

can acquired traits be inherited

no

does a a population or individual evolve over time?

individuals do not evolve, its the population which evolves over time 

what did darwin percieve that new species could arise from?

her percieved that new species could arise from ansestral forms through gradual accumulation of adaptations

• formed the diverse group of galapagos finches 

natural selection

a process in which individuals with certain inherited traits tend to survive and reproduce at higher rates because of those traits 

• darwin proposed this as an explanation fro adaptation

key features of natural selection

• individuals with certain heritable traits survive and reproduce at a higher rate than other individuals 

• increases the frequency of adaptations that are favorable in an environment ( if environment changes, natural selection may drive adaptations to new conditions which gives rise to a new species. 

• individuals do not evolve over time but its the population which does 

• natural selection can only increase or decrease heritable traits that are variable in a population 

• the environment varies from place to place and over time . favorable traits will vary with the environment 

what are darwins 2 observations and inferences?

O#1 : members of a pop often vary in their inherited traits

O#2: all species can produce more offspring than the environment can support, and many of these offspring fail to survive and reproduce

I #1: individuals with inherited traits that increase survival and reproduction in an environment tend to produce more offspring than other individuals

I #2: the unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

what are the 4 types of data which support evolution?

1. observation 

2. homology

3. fossil record

4. biogeography 

fossil record

provides evidence of the extinction of species, the origin of new species, and changed within groups over time