T2 Bio SL - speciation, isolation, evolution

species

species

organisms that can mate and produce fertile offspring

morphological definition of species

organisms that share similar traits with one another

biological definition of species

organisms that can interbreed and produce fertile offspring (have to be reproductively compatible).

who created the biological definition of species?

Ernst Mayr, a evolutionary biologist at around 1942.

Population

A group of organisms that live in the same place and can interbreed and reproduce.

Classification

grouping of objects or information based on similarities

Taxonomy

a term used for the categorization of different characteristics for identifying a species.

What are people who do taxonomy called?

Taxonomists. They write the name in Latin as it was the main language used for scientific work.

Binomial Nomenclature (two-part naming system)

A naming system used for naming species founded by Carolus Linnaeus.

Binomial Nomenclature format

genus - species-specific-epithet

species-specific-epithet

describes a characteristic of an organism

What are the scientific names of organisms based on?

unique physical descriptions, traits, characteristics, a person who originally described the organism, someone important, or its environment.

Prezygotic isolation

The isolation between species causing them to be physically unable to mate.

Types of prezygotic isolation

Geological, Behavioral, Mechanical

Geological isolation

divisions of populations due to physical barriers.

Behavioral isolation

two individuals from the same species that decide not to mate due to the differences in courtship behavior.

Mechanical isolation

two individuals from a species that can’t mate due to physical limitations.

Postzygotic isolation

can interbreed but can’t form a zygote.

Genus

name for a group of species.

Speciation

where new species are formed due to the process of evolution.

speciation graph

ancestor —> speciation —> continuous lineage —> species

Continuous Lineage

genetic information passing to the next generation.

Micro evolution

species changing gradually over time. Can be done naturally or by human intervention.

Domestication

Where a plant or animal is trained to adapt to a human environment for cultivation.

what humans do along with domestication

humans intervene the animals and plants’ breeding to only preserve the useful traits in the reproduction.

Where is the gene?

Cell —> nucleus —> chromosomes —> DNA —> Gene (a section of the DNA)

Who was the first person to recognize the normal number of human chromosomes (23 pairs)?

Joe Hin Tjio

Karyotype

When Chromosomes are arranged from largest to smallest, by banding pattern, and the centromere.

Chromosomes

holds genetic information. Chromosome numbers stay the same within every species.

Autosomes

Chromosomes that do not determine the gender of an individual (22 pairs)

Sex Chromosomes

Chromosomes that determine the gender of an individual (1 pair)

what sex chromosome implies that its a female?

XX

what sex chromosome implies that its a male?

XY

Evolution

The gradual change of a species over time

3 types of evidence gathered by scientists to support evolution

1. Comparative Anatomy and Structures

2. Biochemistry (proteins and DNA)

3. Selective breeding of domesticated animals and crop plants.

Comparative Anatomy and structures

study of anatomical structures to find similarities and differences between species and to understand if there is a common ancestor between them.

Homologous structures

Parts with a similar basic structure with different form and function

Analogous structures

Parts that have the same function with different structure and no common ancestor.

Biochemistry

1. Similarity of proteins, RNA, and DNA molecules.

2. The more closely related organisms are, the more similar the biological makeup.

3. This shows the common ancestor.

4. The genetic code is shown universally and there is similar chemistry and structure of chromosomes among eukaryotes.

Selective breeding of domesticated animals and crop plants

the intervention of humans in the natural breeding process to speed up the process and acquire a result that would provide useful traits.