evolution grade 11 bio uni

Leclerc (1700)

Species may change over time

and that’s humans are similar to apes

Mary anning (early 1800s)

Discovery of the fossil

Georges Cuvier (early 1800s)

Acknowledged annings work

Developed palaeontology

Proved that species go extinct

Charles lynell (mid 1800s)

Uniformitarianism— geological changes occur slowly and continuously (erosion of mountains)

Jeans baptiste Lamarck (early 1800s)

Inheritance of acquired characteristics

Characteristics passed to offspring

Charles Darwin (mid 1800s)

1: species were not created in their present form— but evolved from ancestral species

2: proposed that natural selections was the mechanism for evolution

Natural selection

Over time— life has changed— and will continue to change. Individuals with favourable traits are more likely to leave more offspring better suited for their environment

Wallace agreed with Darwin’s 4 main theories

1) organisms can produce more offspring than can survive— organisms compete for limited resources

2) individuals of a population vary, variations are inheritable

3) individuals that are better suited for local conditions survive to produce more offspring

4) processes for changes are slow

What term did Darwin hate and why?

Evolution— which implies progress. Instead he used “descent with modification”

Artificial selection

Selective breeding of domesticated organisms by humans

what are the 5 sources of evidence of evolution?

1) Fossil record

2) Biogeography

3)comparative anatomy

4) comparative Embryology

5) molecular biology

what is fossil record?

fossils appear in the soil in chronological sedimentary layers

(shows how animals may have evolved over time and how different species relate to one another. )

Ice allows for _____ analysis

Amber hardened ______ of pine

DNA

Resin

what is biogeography?

When there are geographical changes which influence a species evolution according to Continental or plate tectonics

Comparative Anatomy

structures that are similar because of common ancestry

what are the three types of structures?

Homologous, Analogous and vestigial structures.

Homologous structures

are anatomical features that share a common origin but may serve different functions in different species.

Analogous structures

are anatomical features that perform similar functions in different species but do not share a common evolutionary origin.

what is a vestigial structure?

is an anatomical feature that has lost its original function through evolution, often remnants of structures that were functional in ancestral species.

comparative embryology

is the study of the similarities and differences in the embryonic development of different species, providing insight into evolutionary relationships.

molecular biology

genomes can now be studied to reveal sim and diff. helps us better understand mutations

microevolution

is the small-scale evolution that occurs within populations, leading to changes in allele frequencies over time and often resulting in adaptation to local environments.

macroevolution

is the large-scale evolutionary change that occurs over geologic time, resulting in the emergence of new species.

what are the five mechanisms of evolution?

natural selection, sexual selection, artificial selection, genetic drift, gene flow

what is natural selection

envm increases frequency of alleles which provides a reproductive advantage. the envm will place a selective pressure on certain phenotypes

what are the three variations of natural selection?

A) stabilizing selection (somewhere right in the middle (skinny, medium, fat mouse)

B) directional selection (one extreme trait against the other extreme)

C) disruptive selection (both extremes against moderate traits)

what is sexual selection?

males attract females (peacock)

artificial selection?

intentional breeding for favourable traits

genetic drift?

a chnage in the gene pool of a pop due to random occurances

there are two types of genetic drifts, what are they?

a) the bottlenose effect (change in gene pool due to natural disaster or human) ends in reduction variability

b) founder effect (colonization of a land mass due to transport)

gene flow

exchange of genes between populations

what is a species?

organisms that are fertile and able to produce fertile hybrids

speciation?

production of a new species but that seem to be reproductively isolated

what are the two types of barriers?

prezygotic and postzygotic barriers

what are the 5 prezygotic barriers?

1) temporal (breeding occurs dif seasons🌷❄🍁🍂)

b)habitat (breed diff habitats 🏔🏜)

3) behavioral (different species have different ways of attracting a mate👨‍🎤🕺)

4) mechanical (the sex bits don’t fit 👉❌👌)

5) gametic (gametes die before uniting or fail to unite) (usually external fertilizers)

ISOLATION

3 types of postzygotic barriers?

1) hybrid inviability (zygotes fail to develop or to reach sexual maturity)

2) hybrid sterility (hybrid fails to produce functional gametes)

3) hybrid breakdown (offspring of hybrids are weak and infertile)

prezygotic barriers?

prevents organism from even forming.

postzygotic barriers?

barriers after zygote forms

the two modes of speciation

1) allopatric (when ancestral pop is separated and looses genetic variation and becomes its own species)

2) sympatric (radical change in genome this is a rare occurrence)

what are the three patterns of evolution

1) divergent (an ancestral species gives rise to a number of 2 or more of new species)

2) convergent evolution (species that may resemble each other because they live in similar envm)

3) co-evolution (one species evolves in response to another species evolution)

2 interpretations of speciation

1) gradualist model- slow changes in species overtime

2) punctuated equilibrium- evolutions occurs in spurts of relatively rapid change

what is gradualism?

new species arises through the gradual transformation of ancestral species

punctuated equilibrium

species evolve very rapidly, in small isolated populations